Troubleshooting

For complete coverage of all troubleshooting, see the Troubleshooting Section of Service Manual, Form No. SENR3910. The Troubleshooting Section contains five modules: Electronic Troubleshooting, Form No. SENR3913, Mechanical Troubleshooting, Form No. SENR4248, Performance Troubleshooting, Form No. SENR4249, OEM Systems Troubleshooting, Form No. SENR4250, and Jake Brake Troubleshooting, Form No. SENR4251.

Engine Vibration Troubleshooting

The troubleshooting chart provides a definite sequence to be followed for a logical procedure to determine the frequency and amplitude of vibration so that the source of the vibration can be located and corrected.

1. The customer must be asked questions to determine whether his complaint is valid, or whether his diagnosis of the actual problem is correct.

Some of the questions that must be asked are as follows:

a. What components are vibrating?

b. In what speed range does this vibration become excessive?

c. Does clutch operation affect the vibration?

d. What is the history of the problem?

2. Run the engine through the idle speed range and note all vibrating components. Look for any loose or broken mounts, brackets, and fasteners. Repair and tighten any fixtures.

3. Check idle speed range with clutch disengaged. If vibrations subside, there is a balance problem with the clutch disc. The clutch disc must be repaired or replaced.

4. Further analysis requires the use of a vibration instrument. Any instrument which can accurately measure the displacement of the vibration (usually in mils-inch/1000) and the frequency (cycles per second) will be sufficient.

NOTE: The 4C3030 Vibration Analyzer Group can be used to provide a quick and complete identification of all vibration frequencies present in a constant speed measurement. Make reference to Operation Manual, Form No. NEHS0525 for additional information for troubleshooting vibration complaints with the 4C3030 Vibration Analyzer Group.

NOTE: The following steps assume the use of a vibration instrument such as the IRD Mechanalysis Model 320 or an equivalent instrument can be used to analyze vibration. Make reference to Special Instruction, Troubleshooting Engine Vibration In Vehicular Equipment, Form No. SEHS7914 for additional information for troubleshooting vibration complaints.

5. Measure vibration of cab components which have the objectionable vibration.

Run engine slowly through the speed range and measure vibration with the instrument filter OUT. When peak amplitudes are found, run the engine at the speeds they occur and with the instrument filter IN, find the frequency of the vibration.

If the frequency of vibration is 1/2 times of engine rpm (1/2 order), the vibration is caused by a cylinder misfiring. This must be corrected before further vibration analysis is made.

If the frequency of vibration is 3 times engine rpm (3rd order), no corrective action can be taken on the engine because this is the firing frequency of the 3176 Engine. The problem is in the cab or chassis resonance.

If frequency is some order other than 1/2 or 3rd order vibrations, then further measurements must be made on the engine.

6. Measurements taken on the engine must be made perpendicular to the crankshaft at the front and rear of the engine in vertical and horizontal directions.

7. Record all vibrations over 4.0 mils and the engine rpm at which it occurs (100 rpm intervals are sufficient) with instrument filter OUT. Note any sudden increase and decrease in amplitudes. These occur in resonant speed ranges.

If no amplitudes exceed 4.0 mils, the engine is within Caterpillar Specs.

If amplitudes exceed 4.0 mils, the vibrations must be measured with the instrument filter IN to obtain the frequency of the vibrations.

8. Run the engine at high idle. With the instrument filter IN, check the frequency range and record any amplitudes over 4.0 mils and the corresponding frequency. Analysis of vibrations for the possible causes is done by identifying the frequency of the vibration and where on the engine it is the greatest magnitude.

Engine Vibration Troubleshooting

Electronic Control System

General Information

Various sensors feed engine and vehicle data to the electronic control module (ECM). The standard "package" of sensors monitor engine rpm and timing, throttle position, coolant temperature, boost pressure, vehicle speed, cruise control switches status (on/off and set/resume), clutch switch, brake switch, and parking switch. The ECM processes this data and sends electronic signals to the fuel injector pump solenoids. The solenoids are energized and deenergized to start and stop, respectively, the fuel discharge from the fuel injection pumps. See the topic, Electronically Controlled Unit Injector, for a complete explanation of the fuel injection process.

Data Link

The engine incorporates a DATA LINK intended for communication with other microprocessor based devices that are compatible with the proposed American Trucking Association (ATA) and SAE standard. The DATA LINK follows SAE recommended practice J1708 for the hardware description and recommended practice J1587 for the data protocol.

The DATA LINK can reduce duplication of truck sensors by allowing controls to share information. The DATA LINK is used to communicate engine information to other electronic vehicle control systems and to interface with Caterpillar service tools [Electronic Control Analyzer and Programmer (ECAP) and Digital Diagnostic Tool (DDT)].

The engine/vehicle information that is monitored and available on the DATA LINK include the following:

Boost PressureCold Start StatusCoolant TemperatureCruise Control StatusCruise Control Set SpeedEngine IdentificationEngine Systems StatusEngine Speed-rpmFault ParameterFuel Consumption RateIdle Shutdown Timer Status

Calibration (road speed limit-mph, cruise control high speed set limit, cruise control low speed limit, PTO high limit) Fuel PressurePercent ThrottlePTO Control StatusPTO Control Set RPMRetarder Enable Status

Calibration (rated speed-rpm and rated power-bhp) Vehicle Speed-mphVehicle Speed Limit Status

Either the Electronic Control Analyzer and Programmer (ECAP) or the Digital Diagnostic Tool (DDT), can be used to program the customer specified parameters.

One method of programming the customer specified parameters that are selected by a customer, the Electronic Control Analyzer and Programmer (ECAP), is used. The tool plugs into the data link connector to communicate with the ECM. The (ECAP) can be also be used to display real time values of all information available on the data link for diagnosing engine problems.

ECAP Connection To The Data Link
(1) J8 Connector (of the Data Link to the ECM). (2) ECAP. (3) P8 Connector (of the Data Link to the cab). (4) "T" Harness (8T5275)

To read or reprogram the customer specified parameters, or test the electronic control system for faults, an ECAP service tool must be connected to the Data Link. See Electronic Troubleshooting, Form No. SENR3913, for a complete explanation of this connection and the functions of the ECAP.

Programming of the customer specified parameters can be password protected to prevent unauthorized tampering or changing of the customer selected limits. With the proper customer passwords, changing of limits such as Low Gears #1 RPM Limit (LoGr #1), Vehicle Speed Limit (VSL), Low Cruise Control Set Limit (LCC), etc. is quickly and easily accomplished.

Testing And Adjusting

Reprogramming the ECM to operate within a different engine horsepower family requires a different personality module and engine iron change. A Caterpillar dealer should be consulted for details on how to obtain the factory passwords required for this change.

An alternative method of programming the customer specified parameters that are selected by the customer can be done with the Digital Diagnostic Tool (DDT). This tool also plugs into the data link connector to communicate with the ECM. The DDT, however, does not accept alpha/numeric passwords (all "factory" passwords are alpha/numeric). Thus, the DDT cannot be used to program full load setting (FLS), full torque setting (FTS), the personality module code, or the engine serial number. Also, the DDT cannot be used to perform the electronic timing. The ECAP, with a 7X1200 Timing Adapter Group and an 8C9995 Plate, are required to perform electronic timing. See the topics, Checking Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP, and Calibrating Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP for a complete description of this procedure.

The DDT will read "active" or current diagnostic fault codes which are generated by the ECM. The ECAP will read current, as well as "logged" or intermittent diagnostic fault codes that the ECM generates. A partial list of the diagnostic fault codes is listed below.

System Fault Codes

For a complete listing of the diagnostic fault codes and an explanation of each, see 3176 Electronic Troubleshooting, Form No. SENR3913.

Installation/Removal Of The Speed/Timing Sensor

Engine-Front Right Side
(1) P9/J9 Connector. (2) Speed/timing sensor. (3) Front gear cover.

1. Disconnect speed/timing connector P9/J9 (1) and inspect for corrosion, bent or missing pins and sockets, and mismating, broken wires, etc.

2. Remove the speed/timing sensor (2) from front gear cover (3).

3. Examine the plastic end of the sensor for signs of wear or contaminants such as metal filings. The plastic end of the speed/timing sensor should have no contaminants or show no wear [greater than 0.051 mm (.0020 in) from its face].

4. Use a screwdriver to carefully pry the plastic sensor end to the fully EXTENDED position [approximately 4.775 mm (.1880 in) beyond the metal housing of the sensor].

5. Grasp the plastic end of the sensor and gently attempt to wiggle it from side to side to check for freeplay. There should be no looseness.

6. Gently push in on the plastic end of the sensor. The plastic end should be firm and resist movement in the retract direction. If there is no resistance replace the sensor.

Locating Top Center
(4) Bolts (two-6V5219). (5) Cover. (6) Flywheel housing.

7. Remove two bolts (4) and remove cover (5) from the flywheel housing (6) to open the hole for engine turning.

8. Put one of the 6V5219 bolts (4) in the timing hole located approximately 127 to 152 mm (5 to 6 in) above the hole in the flywheel housing for engine turning. Use the 9S9082 Engine Turning Tool and a1/2 inch drive ratchet wrench to turn the engine flywheel in the direction of normal engine rotation (counterclockwise when viewed from the flywheel end) until the timing bolt engages with the threaded hole in the flywheel.

NOTE: The No. 1 piston must be at either top center of the compression stroke or top center of the exhaust stroke.

9. To install the speed/timing sensor, first perform the sensor inspections described in steps 3 through 6.

10. If the sensor end is not fully extended, use a screwdriver to carefully pry the plastic sensor end to the fully EXTENDED position [approximately 4.775 mm (.1880 in) beyond the metal housing of the sensor].

11. Examine the O-ring seal at the base of the sensor threads. If it is missing or damaged, install a new O-ring seal.

12. Install the speed/timing sensor into the front gear cover. Tighten to a torque of 23.5 ± 3.5 N·m (17.5 ± 2.5 lb ft).

13. Connect the P9/J9 connector for the speed/timing sensor near the coolant inlet pipe on the top of the engine.

NOTE: Be sure that the P9/J9 lock ring is properly "locked".

NOTE: The electronic injection timing must be recalibrated after reinstallation of the speed/timing sensor (see the topic, Calibrating Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP).

Throttle Position Sensor Adjustment

NOTE: If the vehicle is equipped with the Pedal-Mounted Throttle Sensor, no adjustment is required. If the vehicle is equipped with the Throttle Position Sensor the following adjustments should be made.

Throttle Position Sensor
(1) Rotary disc. (2) Pin.

1. Inspect the throttle linkage for loose, bent, broken, missing, or worn components. The throttle linkage should work smoothly without excessive drag and return to the low idle position without assistance in less than 1 second. Replace parts if needed.

2. Disconnect the 3176 data link connector (P8/J8 connector) from the truck harness and connect either the ECAP or DDT to the 3176 data link connector.

3. Install a 9-pin "T" at P7/J7 and connect the 8C9801 Frequency Probe to pin E (see Special Instruction, Form No. SEHS8807).

4. Turn the ignition switch to the ON position to provide power to the 3176 control module.

5. Select the Status Mode from the main menu that has THROTTLE POSITION for one of the displays (see Service Tool Special Instructions). The ECAP or DDT will display throttle readings from 0 to 100 percent (no throttle to full throttle).

6. Observe the Duty Cycle of the throttle signal (pin E of P7/J7) using the ECAP or DDT (see Special Instruction, Form No. SEHS8807). The Duty Cycle readings range from 15 to 20% at low idle position. A slight movement of the pedal off the low idle stop should increase the Duty Cycle readings.

7. Actuate the throttle and return to the low idle position.

Correct Low Idle Position Adjustment

8. Adjust either the linkage low idle stop, if the system has one, or the throttle linkage until pin (2) is centered between the mechanical stop and the low idle edge indicator as shown.

Correct High Idle Position Adjustment

9. A Duty Cycle reading of 80 to 85% should be displayed on the ECAP or DDT. A slight movement of the pedal off the high idle stop should decrease the Duty Cycle readings.

10. Adjust either the linkage high idle stop, if the system has one, or the throttle linkage until pin (2) is centered between the mechanical stop and the high idle edge indicator as shown. The high idle edge indicator is approximately in alignment with the center of pin (2) at this position.

11. Repeat Steps 7 through 9 as needed until the low and high idle adjustments are correct. Make sure the two mechanical stops on rotary disc (1) do not contact pin (2) during operation.

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NOTICE
Continued operation against pin (2) can result in failure of the sensor.

12. Turn power off to the 3176 control module.

13. Disconnect the ECAP or DDT from the PEEC control module. Connect the 3176 data link connector to the truck harness.

Pedal-Mounted Throttle Sensor (If Equipped)

Pedal-Mounted Throttle Sensor

If the vehicle is equipped with the Pedal-Mounted Throttle Sensor, no adjustment is required.

The Pedal-Mounted Throttle Sensor can be installed in place of the Throttle Position Sensor on earlier engines as long as the engine has the correct personality module.

The Pedal-Mounted Throttle Sensor is mounted on the back of the OEM-supplied pedal. No adjustments are required for the Pedal-Mounted Throttle Sensor. Calibration of the Pedal-Mounted Throttle Sensor is done automatically by the ECM. The correct calibration can be displayed with the ECAP or the DDT. The correct percent throttle (governor control movement) is displayed as 3% with the throttle completely released, and 100% with the throttle completely depressed.

Fuel System

Either too much fuel or not enough fuel for combustion can be the cause of a problem in the fuel system. Many times work is done on the fuel system when the problem is really with some other part of the engine. The source of the problem is difficult to find, especially when smoke comes from the exhaust. Smoke that comes from the exhaust can be caused by a defective unit injector, but it can also be caused by one or more of the reasons that follow:

a. Not enough air for good combustion.

b. An overload at high altitude.

c. Oil leakage into combustion chamber.

d. Not enough compression.

e. Fuel injection timing incorrect.

Fuel System Components
(1) Fuel priming pump. (2) Fuel supply and return manifold. (3) ECM. (4) Fuel filter base (remote mounted fuel filter base as an attachment). (5) Fuel filter. (6) Fuel pressure sensor. (7) Fuel line (filter base to supply manifold). (8) Fuel line (ECM to fuel filter base). (9) Fuel line (fuel transfer pump to ECM). (10) Fuel transfer pump. (11) Fuel outlet (from fuel transfer pump). (12) Fuel inlet (to fuel transfer pump).

Fuel System Inspection

A problem with the components that send fuel to the engine can cause low fuel pressure. This can decrease engine performance.

1. Check the fuel level in the fuel tank. Look at the cap for the fuel tank to make sure the vent is not filled with dirt.

2. Check fuel lines (7), (8), and (9) for fuel leakage. Be sure none of the fuel lines have a restriction or a defective bend.

3. Install a new fuel filter (5).

4. Remove any air that may be in the fuel system. Use the fuel priming pump to move fuel through the low pressure part of the system. Fuel with air will return to the tank through the fuel return manifold and fuel return line.

To remove air from the unit injector pumps, loosen the fuel return line from the fuel supply and return manifold block. Crank engine with the starter motor until fuel without air comes from the fuel line connection. Tighten the fuel return line connection.

NOTE: The fuel priming pump will not give enough pressure to push fuel through the unit injector pumps.

Fuel Transfer Pump

With the engine operating at rated rpm and load condition, the fuel transfer pump moves fuel through the ECM, fuel filter base, and fuel supply and return manifolds. A pressure regulating relief valve, in the return fuel manifold, regulates the fuel pressure at approximately 550 kPa (80 psi) at rated rpm. The minimum fuel pressure must be 445 kPa (65 psi) or greater at rated rpm.

If the fuel pressure is not above the minimum specifications, stop the engine. Make a replacement of the fuel filter, and make sure the fuel lines are not plugged or damaged.

Start the engine and again check the fuel pressure. If the fuel pressure is not above the minimum specification, a repair or replacement of the fuel transfer pump or a replacement of the pressure regulating relief valve is needed.

Fuel Pressure

To check the fuel transfer pump pressure, remove the fuel pressure sensor from the fuel filter base. Install a pressure gauge, and start the engine.

1U5470 Engine Pressure Group

The 1U5470 Engine Pressure Group can be used to check engine fuel pressure.

This tool group has a gauge to read fuel pressure to the fuel supply manifold. Special Instruction, Form No. SEHS8907 is with the tool group and gives information for its use.

NOTE: An ECAP or DDT can also be used to check the fuel transfer pump pressure.

To read the fuel transfer pump pressure with the ECAP or the DDT, connect the service tool to the Data Link. See Electronic Troubleshooting, Form No. SENR3913, for a complete explanation of this connection and the functions of the ECAP or the DDT.

Unit Injector Adjustment

Injector Mechanism
(1) Rocker arm. (2) Adjusting screw. (3) Locknut.

To make an adjustment to the unit injector, turn the adjusting screw in the rocker arm. Unit injector adjustment can be make by using the procedure that follows:

1. Put No. 1 piston at top center (TC) on the compression stroke. See the topic, Finding Top Center Position For No. 1 Piston.

2. Turn the unit injector adjusting screw (2) CW (clockwise) until contact is made with the unit injector.

3. Turn the adjusting screw CW (clockwise) an additional 180° (1/2 turn).

4. Hold the adjusting screw in this position and tighten the locknut (3) to a torque of 55 ± 10 N·m (41 ± 7 lb ft).

5. Make an adjustment to the unit injectors on cylinders 3, 5, and 6.

6. Remove the timing bolt and turn the flywheel 360° in the direction of engine rotation (counterclockwise). This will put No. 1 piston at top center (TC) on the exhaust stroke.

7. Make an adjustment to the unit injectors on cylinders 1, 2, and 4.

8. Remove the timing bolt from the flywheel when all the unit injector adjustments have been made, and reinstall the timing cover.

Checking Engine Cylinders Separately

Temperature of an exhaust manifold port, when the engine runs at low idle speed, can be an indication of the condition of a fuel injector. Low temperature at an exhaust manifold port is an indication of no fuel to the cylinder. This could be caused by an inoperative injector pump. Extra high temperature at an exhaust manifold port can be an indication of too much fuel to the cylinder, caused by a malfunctioning injector pump.

Use the 1U8865 Infrared Thermometer to check exhaust temperature. The Operator's Manual, Form No. NEHS0510, for the 1U8865 Infrared Thermometer gives complete operating and maintenance instructions for this tool.

Static Check Of The Timing Gear Position Used To Reference Electronic Injection Timing/Front Gear Group Alignment

Front Gear Group (with front cover removed)
(1) Camshaft gear/timing reference ring. (2) Timing marks. (3) Idler gear. (4) Crankshaft.

The basis for correct fuel injection timing and valve mechanism operation is determined by the timing reference ring and the alignment of the front gear group. The timing reference ring is located on the end of the camshaft group, and it is used to measure crankshaft rotation. During installation of the front gear group, timing marks (2) on idler gear (3) must be in alignment with the timing marks on crankshaft gear (4) and the timing marks on camshaft gear (1). For a complete removal and installation procedure of the front gear group, see the topic, Front Gear Group, in the Disassembly and Assembly module.

Check for proper alignment of the timing reference ring (1) on the camshaft/weight assembly. The timing reference ring is fastened to the camshaft weight with a plate and nine bolts. Turn out the nine bolts part way, and inspect the key between the timing reference ring and the weight. Check the timing ring teeth. The teeth should not be defaced, and should have sharp clean edges and be free of contaminants.

NOTE: The electronic injection timing must be calibrated after re-assembly of the front gear train.

Finding Top Center Position For No. 1 Piston

Locating Top Center
(1) Bolts (two-6V5219). (2) Cover. (3) Flywheel housing.

1. Remove two bolts (1) and remove cover (2) from the flywheel housing (3) to open the turning hole.

2. Put one of the 6V5219 bolts (1) in the timing hole located approximately 127 to 152 mm (5 to 6 in) above the turning hole in the flywheel housing. Use the 9S9082 Engine Turning Tool and a 1/2 inch drive ratchet wrench to turn the engine flywheel in the direction of normal engine rotation (counterclockwise when viewed from the flywheel end) until the timing bolt engages with the threaded hole in the flywheel.

NOTE: If the flywheel is turned beyond the point that the timing bolt engages in the threaded hole, the flywheel must be turned opposite normal engine rotation approximately 30°. Then turn the flywheel in the direction of normal rotation (counterclockwise) until the timing bolt engages with the threaded hole. The reason for this procedure is to make sure the play is removed from the gears when the No. 1 piston is put on top center.

3. Remove the front valve cover from the engine.

4. The intake and exhaust valves for the No. 1 cylinder are fully closed if No. 1 piston is on the compression stroke and the rocker arms can be moved by hand. If the rocker arms cannot be moved and the valves are slightly open, the No. 1 piston is on the exhaust stroke.

NOTE: When the actual stroke position is identified, and the other stroke position is needed, it is necessary to remove the timing bolt from the flywheel, turn the flywheel counterclockwise 360°, and reinstall the timing bolt.

Checking Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP (Electronic Control Analyzer And Programmer)

1. Turn the engine off at the ignition switch.

Magnetic Pick-up Sensor
(1) Magnetic pick-up sensor. (2) Adapter sleeve for magnetic pick-up.

Timing Adapter Module Installed On ECAP
(3) ECAP. (4) Timing adapter module. (5) Cable for magnetic pick-up.

2. Install the 8C9995 Module Adapter Plate on the ECAP (3). Install timing adapter module (4) to the module adapter plate. Connect cable (5) for the magnetic pick-up to the timing adapter module.

3. Put No. 1 piston at top center on the compression stroke. See the topic, Finding Top Center Position For No. 1 Piston.

4. Remove the timing calibration plug from the right side of the engine cylinder block. The plug is located on the number 4 cylinder rod pocket. Install adapter sleeve (2) into the hole for the plug.

Installed Magnetic Pick-up Sensor
(1) Magnetic pick-up sensor. (2) Adapter sleeve for magnetic pick-up. (6) Counterweight. (7) TDC slot. (A) 1.02 mm (.040 in).

5. Rotate the engine until #1 cylinder is between 10 and 90 degrees before top dead center (BTDC). This positions the counterweight (6) surface in front of the timing calibration hole.

NOTE: The counterweight must be a minimum of 10 degrees BTDC to make sure the timing probe is positioned on counterweight (6) surface and not TDC slot (7).

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If the crankshaft is not in the correct position when the magnetic pickup sensor is installed, the magnetic probe will be damaged when the engine is started.

6. Slide the magnetic pick-up sensor (1) in the adapter sleeve (2) until it contacts the surface on the No. 4 cylinder counterweight.

7. Pull the magnetic pick-up sensor away from the flat surface approximately 1.02 mm (.040 in).

8. Hand tighten the nut on the adapter sleeve (2) to secure the magnetic pick-up in place.

9. Connect cable for magnetic pick-up (5) to the magnetic pick-up sensor.

ECAP Hookup (engine-left side)
(3) ECAP. (8) "T" harness (8T5275). (9) Injection "T" harness (7X1170).

10. Connect an ECAP (3) to either the Data Link connector at the dash (if available) or install a "T" harness (8) between the P8/J8 connector for the ECAP.

11. Disconnect the bulkhead connector P5/J5 in the valve cover base and install the injection "T" harness (9) as shown. Connect the end of the harness to the timing adapter module on the ECAP.

12. Warm the engine up and check for engine faults:

Start the engine and run at low idle until the engine has warmed up enough to change from the cold mode operation to the warm mode operation. If equipped, turn the cruise control ON/OFF switch to the OFF position. The "check engine" lamp should go out after the engine has started and the 10 second lamp test is complete. The engine rpm will decrease from approximately 1000 rpm while in the cold mode to the programmed low idle rpm when in the warm mode.

If the "check engine" lamp stays on continuously, the electronic control system has detected a fault. Follow the Engine Test Procedure Number P-200 in Electronic Troubleshooting, Form No. SENR3913, to determine the fault code.

If the "check engine" lamp is flashing on and off intermittently, the electronic control system is detecting an intermittent fault. Follow the Engine Test Procedure Number P-200 in Electronic Troubleshooting, Form No. SENR3913, to determine the fault code.

If the engine low idle rpm is greater than the programmed low idle rpm while in the warm mode, follow the Engine Test Procedure Number P-701 or P-700 in Electronic Troubleshooting, Form No. SENR3913 to check the throttle position sensor adjustment.

13. Select the 3176 Monitor Timing screen on the ECAP (see the ECAP special instruction).

NOTE: The engine must be in the "warm mode" of operation for valid results.

14. Observe the "Desired Timing" bar display on the ECAP. Run the engine at different rpm's using the throttle or PTO switches if available. The "Actual Timing" and "Desired Timing" bar display on the ECAP should change with engine rpm.

NOTE: To insure the most accurate timing calibration, the engine rpm should be held as steady as possible at approximately 1500 rpm. This can be performed using the PTO engine governor or a steady foot on the accelerator pedal. Any major changes (greater than 100 rpm) will slow down the procedure and make it less accurate.

The end of the "Desired Timing" bar display should always be located within the two vertical "Actual Timing" tolerance lines. If the "Desired Timing" bar is NOT within the two vertical timing tolerance lines, the timing calibration is incorrectly set.

Recalibrate the injection timing (see the topic, Calibrating Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP), and repeat Step 13 after recalibration.

If the "Desired Timing" bar is NOT within the two vertical timing tolerance lines, or not present AND the display is erratic, be sure the tool installation is correct and none of the tools are at fault.

Recalibrate the injection timing (see the topic, Calibrating Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP), and repeat Step 13 after recalibration.

If the "Desired Timing" bar display is out of range, but engine rpm is properly displayed on the ECAP, the timing reference ring may be at fault. See the topic, Static Check Of The Timing Gear Position Used To Reference Electronic Injection Timing/Front Gear Group Alignment.

Calibrating Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP (Electronic Control Analyzer And Programmer)

1. Check the electronic injection timing (see the topic, Checking Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP).

2. Select the 3176 Timing Calibrate Screen on the ECAP.

NOTE: To insure the most accurate timing calibration, the engine rpm should be held as steady as possible at approximately 1500 rpm. This can be performed using the PTO engine governor or a steady foot on the accelerator pedal. Any major changes (greater than 100 rpm) will slow down the procedure and make it less accurate.

3. Press on the "space" key on the ECAP and wait until the ECAP indicates timing is CALIBRATED (approximately 15 seconds).

4. Verify that timing has been calibrated by observing the "Desired Timing" bar display on the ECAP. Run the engine at different rpm's using the throttle or PTO switches if available.

If the ECAP display reads COULD NOT CALIBRATE timing, the electronic injection timing has NOT been set. Recheck the tool installation and tool operation. The engine must not have any diagnostic fault conditions present during timing calibration and the engine speed must remain stable (± 50 rpm). Also, engine load must remain stable. Follow Engine Test Procedure Number P-200 in Electronic Troubleshooting, Form No. SENR3913, to check for diagnostic faults, and if none are present try again to calibrate electronic injection timing (see the topic, Calibrating Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP). If the timing will still not calibrate, see Step 5.

If the ECAP display reads that injection timing is CALIBRATED, but during verification, the actual timing bar display is not within the two vertical timing tolerance lines and/or the display is erratic, first repeat the timing calibration procedure. If injection timing is still inconsistent, see Step 5.

5. The engine must not have any diagnostic fault conditions present during injection timing calibration. Follow Engine Test Procedure Number P-200 in Electronic Troubleshooting, Form No. SENR3913, to check for diagnostic faults.

NOTE: Engine rpm and engine load must remain stable during injection timing calibration. If the engine speed is not stable, injection timing will not calibrate. Correct the cause of the rpm instability, and then calibrate the injection timing. (see Mechanical Troubleshooting, Form No. SENR4248 for identifying and repairing the cause of the rpm instability).

Excessive backlash in the engine gear train will cause erratic or inconsistent timing or may prevent injection timing calibration. (see Mechanical Troubleshooting, Form No. SENR4248 for identifying and repairing a gear train problem).

Be sure the tools are properly installed and are not at fault. (see the timing adapter instructions). A faulty ECM on the engine may cause erratic injection timing or may prevent injection timing calibration. This, however, is not likely.

Electronic Injection Timing Troubleshooting

Electronic injection timing troubleshooting is required if the electronic injection timing is inconsistent or it will not calibrate correctly. If either of these conditions are present, see Step 5 of the topic, Calibrating Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP. Also, see Electronic Troubleshooting, Form No. SENR3913.

Engine Speed Measurement

6V3121 Multitach Group

The 6V3121 Multitach Group can measure engine speed from a magnetic pickup on the flywheel housing. It also has the ability to measure engine speed from visual engine parts in rotation.

Special Instruction, Form No. SEHS7807 is with the 6V3121 Multitach Group and gives instructions for the test procedure.

NOTE: An ECAP or DDT can also be used to check engine rpm.

Air Inlet And Exhaust System

Restriction Of Air Inlet And Exhaust

There will be a reduction of horsepower and efficiency of the engine if there is a restriction in the air inlet or exhaust system.

Air flow through the air cleaner must not have a restriction (negative pressure difference measurement between atmospheric air and air that has gone through air cleaner) of more than 635 mm (25 in) of water with a used or plugged air cleaner element. Air flow through the air cleaner must not have a restriction (negative pressure difference measurement between atmospheric air and air that has gone through air cleaner) of more than 381 mm (15 in) of water with a new air cleaner element.

Back pressure from the exhaust (pressure difference measurement between exhaust at outlet elbow and atmospheric air) must not be more than 1016 mm (40 in) of water.

Measurement of Pressure in Inlet Manifold

The efficiency of an engine can be checked by making a comparison of the pressure in the inlet manifold with the information given in the Fuel Setting And Related Information Fiche. This test is used when there is a decrease of horsepower from the engine, yet there is no real sign of a problem with the engine.

The correct pressure for the inlet manifold is given in the Fuel Setting And Related Information Fiche. Development of this information is done with these conditions:

a. 737 mm (29 in) of mercury (DRY) barometric pressure.

b. 29°C (85°F) outside air temperature.

c. 35 API rated fuel.

On a turbocharged and aftercooled engine, a change in fuel rating will also change horsepower and the pressure in the inlet manifold. If the fuel is rated above 35 API, pressure in the inlet manifold can be less than given in the Fuel Setting And Related Information Fiche. If the fuel is rated below 35 API, the pressure in the inlet manifold can be more than given in the Fuel Setting And Related Information Fiche. BE SURE THAT THE AIR INLET OR EXHAUST DOES NOT HAVE ARESTRICTION WHEN MAKING A CHECK OF PRESSURE IN THE INLET MANIFOLD.

Pressure Test Location On Inlet Manifold

(1) Plug.

To measure the inlet manifold pressure, remove plug (1) from the inlet manifold. Use the 1U5470 Engine Pressure Group to check the pressure in the inlet manifold.

1U5470 Engine Pressure Group

This tool group has a gauge to read pressure in the inlet manifold. Special Instruction, Form No. SEHS8907 is with the tool group and gives instructions for its use.

NOTE: An ECAP or DDT can also be used to check the boost pressure.

Exhaust Temperature

Use the 1U8865 Infrared Thermometer to check exhaust temperature. The Operator's Manual, Form No. NEHS0510, for the 1U8865 Infrared Thermometer gives complete operating and maintenance instructions for this tool.

Air to Air Aftercooled Systems

Visual Inspection

Inspect all air lines, hoses and gasket connections at each oil change. Make sure the constant torque hose clamps are tightened to the correct torque. Check the truck manufacturer's specifications for the correct torque. Check welded joints for cracks and make sure all brackets are tightened in position and are in good condition. Use compressed air to clean cooler core blockage caused by debris or dust. Inspect the cooler core fins for damage, debris or salt corrosion. Use a stainless steel brush with soap and water to remove corrosion.

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Pressure air can cause personal injury. When using pressure air for cleaning, wear a protective face shield, protective clothing and protective shoes.

NOTE: When air to air aftercooler system parts are repaired and/or replaced, a leak test is recommended.

The use of winter fronts or shutters is discouraged with air to air aftercooled systems. Winter fronts can only be used on truck models where tests have shown that the engine jacket water will overheat before the inlet manifold air temperature is excessive. On these trucks, sensors and gauges or alarms are installed to indicate engine operating conditions before excessive inlet manifold air temperatures are reached. Check with the truck manufacturer on winter front and shutter application.

Air System Restriction

Pressure measurements should be taken at the turbocharger outlet and at the inlet manifold. When the total pressure drop of the charged air system at maximum air flow exceeds 13.5 kPa (4 in Hg), the air lines and cooler core must be inspected for internal restriction and cleaned, repaired or replaced as necessary.

Turbocharger Failure

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Pressure air can cause personal injury. When using pressure air for cleaning, wear a protective face shield, protective clothing and protective shoes. The maximum air pressure must be below 205 kPa (30 psi) for cleaning purposes.

If a turbocharger failure occurs, remove the air to air cooler core and flush internally with a solvent that removes oil and other foreign substances. Shake cooler to eliminate any trapped debris. Wash with hot, soapy water; rinse thoroughly with clean water; and blow dry with compressed air in reverse direction of normal air flow. Carefully inspect the system to make sure it is clean.

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NOTICE
Do not use caustic cleaners or damage to the aftercooler core will result.

Inlet Manifold Pressure

Normal inlet manifold pressure with high exhaust temperature can be caused by cooler core fin blockage. Clean the cooler core fins, see Visual Inspection for the cleaning procedure to use.

Low inlet manifold pressure and high exhaust manifold temperature can be caused by any of the conditions that follow:

1. A plugged air cleaner. Clean or replace the air cleaner as needed.

2. A blockage in the air lines between the air cleaner and turbocharger. All restrictions must be removed.

3. Cooler core leakage. Pressure test the cooler core, see Aftercooler Core Leakage for the correct procedure to use and repair or replace parts as needed.

4. Leakage from the pressure side of the induction system. Check and repair leaks.

5. Inlet manifold leak. Check for loose, missing and damaged fittings or plugs. Also check the manifold to cylinder head gaskets.

Aftercooler Core Leakage

FT1984 Air to Air Aftercooler Test Group
(1) Coupler. (2) Chain. (3) Dust plugs. (4) Nipple. (5) Regulator and valve assembly. (6) Tee. (7) Relief valve.

A low power problem in the engine can be the result of aftercooler leakage. Low power, low boost pressure, black smoke, and/or high exhaust temperature can be the result of an aftercooler system leakage.

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NOTICE
Remove all air leaks from the system to prevent engine damage. In some operating conditions, the engine can pull a manifold vacuum for short periods of time. A leak in the aftercooler or air lines can let dirt and other foreign material into the engine and cause rapid wear and/or damage to engine parts.

A large cooler core leak often can be found by making a visual inspection. To check for smaller leaks, use the following procedure:

1. Disconnect the air pipes from the inlet and outlet side of the aftercooler core.

Tooling Installed (typical example)
(1) Coupler. (2) Chain. (3) Dust plugs.

2. Install couplers (1) and dust plugs (3) from the FT1984 Air to Air Aftercooler Test Group as shown on each side of the aftercooler core. Installation of additional hose clamps on hump hoses is recommended to prevent the hoses from bulging while the aftercooler core is being pressurized.

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Dust plug chains (2) must be installed to the aftercooler core or the radiator brackets to prevent possible injury while testing. Do not stand in front of the dust plugs while testing.

Pressurize System (typical example)
(5) Regulator and valve assembly.

3. Install regulator and valve assembly (5) on the outlet side of the aftercooler. Attach air supply.

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NOTICE
Do not use more than 240 kPa (35 psi) air pressure or damage to the aftercooler core can be the result.

4. Open air valve and pressurize the aftercooler to 205 kPa (30 psi). Shut off air supply.

5. Inspect all connections for air leakage.

6. System pressure should not drop more than 35 kPa (5 psi) in 15 seconds.

7. If the pressure drop is more than specified, use a solution of soap and water to check all areas of possible leakage and look for air bubbles. Replace hoses or repair the aftercooler core as needed.

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To help prevent personal injury when the tooling is removed, relieve all pressure in the system slowly by using air regulator and valve assembly (5).

8. After testing, remove FT Tooling and connect air pipes on each side of the aftercooler.

Dynamometer Test

Air to air aftercooled chassis dynamometer tests, in hot ambient temperatures, can add a greater heat load to the jacket water cooling system, therefore the jacket water cooling system temperature must be monitored. Also, monitor the inlet air temperature as it may need a power correction factor along with fuel API, fuel temperature and barometric pressure.

For engine dynamometer tests, use the FT1438 Dynamometer Testing Aftercooler. FT1438 provides an air to water aftercooler to control the inlet air temperature to 43°C (110°F).

Crankcase (Crankshaft Compartment) Pressure

Pistons or rings that have damage can be the cause of too much pressure in the crankcase. This condition will cause the engine to run rough. There will also be more than the normal amount of fumes (blowby) coming from the crankcase breather. The breather can then become restricted in a very short time, causing oil leakage at gaskets and seals that would not normally have leakage. Other sources of blowby can be worn valve guides or turbocharger seal leakage.

8T2700 Indicator Group

The 8T2700 Indicator Group is used to check the amount of blowby. The test procedure is in Special Instruction, Form No. SEHS8712.

Compression

An engine that runs rough can have a leak at the valves, or have valves that need adjustment. Removal of the head and inspection of the valves and valve seats is necessary to find those small defects that do not normally cause a problem. Repair of these problems is normally done when reconditioning the engine.

Cylinder Head

The cylinder head has valve seat inserts, valve guides and bridge dowels that can be removed when they are worn or have damage. Replacement of these components can be made with the tools that follow. Most of the tools are part of the 1U9654 Head Repair Tool Group.

NOTE: The Disassembly and Assembly module contains a complete procedure for removing and installing the cylinder head components.

Valves

For valve removal and installation use the 5S1330 Valve Spring Compressor Assembly or equivalent, and the 5S1332 Valve Keeper Inserter.

NOTE: A 1U7798 Hammer and 1U7794 Shaft Assembly are used to remove and install the valve seat inserts and valve guides.

Valve Seat Inserts

Tools needed to remove and install the valve seat inserts are: 1U9166 Valve Seat Extractor for intake valves, 1U9167 Valve Seat Extractor for exhaust valves, 1U9170 Valve Seat Driver, and 1U9706 Plate (for exhaust seats).

Valve Guides

Tools needed to remove and install the valve guides are the 1U9168 Valve Guide Collar (Stop) and the 1U9169 Valve Guide Driver.

Checking Valve Guide Bores

Use the 5P3536 Valve Guide Gauge Group to check the bore of the valve guides. Special Instruction, Form No. GMG02562 gives complete and detailed instructions for use of the 5P3536 Valve Guide Gauge Group.

Bridge Adjustment

Intake And Exhaust Valve Mechanism
(1) Adjustment locknut (rocker arm). (2) Rocker arm (intake). (3) Bridge assembly. (4) Adjustment locknut (bridge). (5) Rocker arm (exhaust).

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To prevent possible injury, do not use the starter motor to turn the flywheel. Hot engine components can cause burns. Allow additional time for the engine to cool before measuring valve clearance. The 3176 uses high voltage to the unit injectors. Do not come in contact with the injector terminals while the engine is running.

When the head is disassembled, keep the bridges with their respective cylinders. Adjustment of the bridge will be necessary after the valves are ground or other reconditioning of the cylinder head is done. The bridge should be checked and/or adjusted each time the valves are adjusted. Use the procedure that follows to install and make an adjustment to the bridge.

NOTE: Valves must be fully closed (see the topic, Finding Top Center Position For No. 1 Piston).

1. Remove the valve covers from the engine.

2. Lubricate the bridge dowel, bridge bore, and top pad of the bridge assembly with engine oil.

3. Install the bridge assembly on the bridge dowel.

4. While firmly pressing [0.5 to 4.5 kg (1 to 10 lb)] straight down on the bridge pad, turn the adjusting screw CW (clockwise) until contact is made with the valve stem.

5. Turn the adjusting screw CW (clockwise) an additional 45° (1/8 turn) to straighten the dowel in the guide and compensate for slack in the threads.

6. Hold the adjusting screw in this position and tighten the adjustment locknut to a torque of 25 ± 7 N·m (18 ± 5 lb ft).

7. Put engine oil at the point where the rocker arms make contact with the bridges.

Valve Clearance Setting

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To prevent possible injury, do not use the starter motor to turn the flywheel. Hot engine components can cause burns. Allow additional time for the engine to cool before measuring valve clearance. The 3176 uses high voltage to the unit injectors. Do not come in contact with the injector terminals while the engine is running. Disconnect J5/P5.

NOTE: Valve clearance is measured between the rocker arm and the bridge for the valves.

NOTE: When the valve lash (clearance) is checked, adjustment is NOT NECESSARY if the measurement is in the range given in the chart for Valve Clearance Check: Engine Stopped. If the measurement is outside this range, adjustment is necessary. See the chart for Valve Clearance Setting: Engine Stopped, and make the setting to the nominal (desired) specifications in this chart.

Cylinder And Valve Location

To make an adjustment to the valve clearance, turn the adjustment screw in the rocker arm. Valve clearance adjustments can be made by using the procedure that follows:

1. Put No. 1 piston at top center (TC) on the compression stroke. See the topic, Finding Top Center Position For No. 1 Piston.

Intake Valve Adjustment
(1) Intake rocker arm. (2) Adjustment locknut.

Exhaust Valve Adjustment
(3) Exhaust rocker arm. (4) Adjustment locknut.

2. Make an adjustment to the valve clearance on the intake valves for cylinders 1, 2 and 4. Make an adjustment to the valve clearance on the exhaust valves for cylinders 1, 3, and 5.

3. After each adjustment, tighten the nut for valve adjustment screw to a torque of 25 ± 7 N·m (18 ± 5 lb ft), and check the adjustment again.

4. Remove the timing bolt and turn the flywheel 360° in the direction of engine rotation. This will put No. 6 piston at top center (TC) on the compression stroke. Install the timing bolt in the flywheel.

5. Make an adjustment to the valve clearance on the intake valves for cylinders 3, 5, and 6. Make an adjustment to the valve clearance on the exhaust valves for cylinders 2, 4, and 6.

6. After each adjustment, tighten the nut for valve adjustment screw to a torque of 25 ± 7 N·m (18 ± 5 lb ft), and check the adjustment again.

7. Remove the timing bolt from the flywheel when all adjustments to the valve clearances have been made.

Jake Brake Adjustment

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To prevent possible injury, do not use the starter motor to turn the flywheel. Hot engine components can cause burns. Allow additional time for the engine to cool before measuring valve clearance. The 3176 uses high voltage to the unit injectors. Do not come in contact with the injector terminals while the engine is running.

NOTE: Slave piston lash is measured between the slave piston and the actuating pin in the bridge adjusting screw.

Jake Brake
(1) Adjusting screw/locknut. (2) Slave piston. (3) Actuating pin (within the bridge adjusting screw assembly).

Make the slave piston adjustments with the engine stopped. The exhaust valves must be closed on the cylinder to be adjusted.

1. Put No. 1 piston at top center (TC) on the compression stroke. See the topic, Finding Top Center Position For No. 1 Piston.

2. Insert a 1.143 mm (.0450 in) feeler gauge between slave piston (2) and actuating pin (3) in the bridge adjusting screw assembly.

3. Turn the slave piston adjusting screw (1) clockwise until the 1.143 mm (.0450 in) is set.

4. Make an adjustment to the slave piston clearance on cylinders 1, 3, and 5.

5. After each adjustment, tighten the nut for valve adjustment screw to a torque of 35 N·m (26 lb ft), and check the adjustment again.

6. Remove the timing bolt and turn the flywheel 360° in the direction of engine rotation. This will put No. 6 piston at top center (TC) on the compression stroke. Install the timing bolt in the flywheel.

7. Make an adjustment to the slave piston clearance on cylinders 2, 4, and 6.

8. After each adjustment, tighten the nut for valve adjustment screw to a torque of 35 N·m (26 lb ft), and check the adjustment again.

9. Remove the timing bolt from the flywheel when all adjustments have been made.

Lubrication System

One of the problems in the list that follows will generally be an indication of a problem in the lubrication system for the engine.

* Too Much Oil Consumption

* Oil Pressure Is Low

* Oil Pressure Is High

* Too Much Bearing Wear

* Increased Oil Temperature

Too Much Oil Consumption

Oil Leakage on Outside of Engine

Check for leakage at the seals at each end of the crankshaft. Look for leakage at the oil pan gasket and all lubrication system connections. Check to see if oil comes out of the crankcase breather. This can be caused by combustion gas leakage around the pistons. A dirty crankcase breather will cause high pressure in the crankcase, and this will cause gasket and seal leakage.

Oil Leakage Into Combustion Area of Cylinders

Oil leakage into the combustion area of the cylinders can be the cause of blue smoke. There are four possible ways for oil leakage into the combustion area of the cylinders:

1. Oil leakage between worn valve guides and valve stems.

2. Worn or damaged piston rings, or dirty oil return holes.

3. Compression ring and/or intermediate ring not installed correctly.

4. Oil leakage past the seal rings in the impeller end of the turbocharger shaft.

Too much oil consumption can also be the result if oil with the wrong viscosity is used. Oil with a thin viscosity can be caused by fuel leakage into the crankcase, or by increased engine temperature.

Measuring Engine Oil Pressure

An oil pressure gauge that has a defect can give an indication of low or high oil pressure

1U5470 Engine Pressure Group

The 1U5470 Engine Pressure Group can be used to measure the pressure in the system. This tool group has a gauge to read pressure in the oil manifold. Special Instruction, Form No. SEHS8907 is with the tool group and gives instructions for its use.

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Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury.

Engine-Right Side
(1) Plug. (2) Plug.

Oil pressure to the camshaft and main bearings should be checked on the side of the cylinder block at oil gallery plugs (1) or (2). Install the 1U5470 Engine Pressure Group into this opening. With the engine at operating temperature (using SAE 15W40 oil), under full load condition, oil pressure should be 275 to 414 kPa (40 to 60 psi). With the engine at operating temperature (using SAE 15W40 oil), at 600 to 800 rpm low idle, minimum oil pressure is 68 kPa (10 psi).

NOTE: An ECAP or DDT can also be used to check the engine oil pressure.

Oil Pressure Is Low

Crankcase Oil Level

Check the level of the oil in the crankcase. Add oil if needed. It is possible for the oil level to be too far below the oil pump supply tube. This will cause the oil pump not to have the ability to supply enough lubrication to the engine components.

Oil Pump Does Not Work Correctly

The inlet screen of the supply tube for the oil pump can have a restriction. This will cause cavitation (low pressure bubbles suddenly made in liquids by mechanical forces) and a loss of oil pressure. Air leakage in the supply side of the oil pump will also cause cavitation and loss of oil pressure. If the bypass valve for the oil pump is held in the open (unseated)position, the lubrication system cannot get to maximum pressure. Oil pump gears that have too much wear will cause a reduction in oil pressure.

Oil Filter Bypass Valve

If the bypass valve for the oil filter is held in the open position (unseated) because the oil filter has a restriction, a reduction in oil pressure can result. To correct this problem, remove and clean the bypass valve and bypass valve bore. Install a new Caterpillar oil filter to be sure that no more debris makes the bypass valve stay open.

Too Much Clearance At Engine Bearings Or Open Lubrication System (Broken Or Disconnected Oil Line Or Passage)

Components that are worn and have too much bearing clearance can cause oil pressure to be low. Low oil pressure can also be caused by an oil line or oil passage that is open, broken or disconnected.

Piston Cooling Jets

When engine is operated, cooling jets direct oil toward the bottom of the piston to cool the piston and also provide lubrication for the piston pin. If a jet is broken, plugged or installed wrong, seizure of the piston will be caused in a very short time.

Oil Pressure Is High

Oil pressure will be high if the bypass valve for the oil pump cannot move from the closed position.

Too Much Bearing Wear

When some components of the engine show bearing wear in a short time, the cause can be a restriction in an oil passage.

If the gauge for oil pressure shows enough oil pressure, but a component is worn because it cannot get enough lubrication, look at the passage for oil supply to the component. A restriction in a supply passage will not let enough lubrication get to a component, and this will cause early wear.

Increased Oil Temperature

With the engine at operating temperature (using SAE 15W40 oil), the maximum oil temperature is 110°C (230°F). This temperature is from or after the oil cooler.

Look for a restriction in the oil passages of the oil cooler. If the oil cooler has a restriction, the oil temperature will be higher than normal when the engine is operated. The oil pressure of the engine will not get low just because the oil cooler has a restriction.

Also check the oil cooler bypass valve to see if it is held in the open position (unseated). This condition will let the oil through the valve instead of the oil cooler, and oil temperature will increase.

Gauges For Oil Pressure

An oil pressure gauge or a sender that has a defect can give an indication of low or high oil pressure.

The 1U5470 Engine Pressure Group can be used to make a comparison with instrument panel gauges.

Cooling System

This engine has a pressure type cooling system. A pressure type cooling system gives two advantages. The first advantage is that the cooling system can have safe operation at a temperature that is higher than the normal boiling (steam) point of water. The second advantage is that this type system prevents cavitation (low pressure bubbles suddenly made in liquids by mechanical forces) in the water pump. With this type system, it is more difficult for an air or steam pocket to be made in the cooling system.

The cause for increased engine temperature is generally because regular inspections of the cooling system were not made. Make a visual inspection of the cooling system before a test is made with test equipment.

Visual Inspection of the Cooling System

1. Check coolant level in the cooling system.

2. Look for leaks in the system.

NOTE: Water pump seals. A small amount of coolant leakage across the surface of the "face-type" seals is normal, and required, to provide lubrication for this type of seal. A hole is provided in the water pump housing to allow this coolant/seal lubricant to drain from the pump housing. Intermittent leakage of small amounts of coolant from this hole is not an indication of water pump seal failure. Replace the water pump seals only if a large amount of leakage, or a constant flow of coolant is observed draining from the water pump housing. See the topic, Water Pump, Disassemble & Assemble, for a complete description of replacement of the water pump seals.

3. Look for bent radiator fins. Be sure that air flow through the radiator does not have a restriction.

4. Inspect the drive belt for the fan.

5. Check for damage to the fan blades.

6. Look for air or combustion gas in the cooling system.

7. Inspect the filler cap and the surface that seals the cap. This surface must be clean.

Testing the Cooling System

Remember that temperature and pressure work together. When a diagnosis is made of a cooling system problem, temperature and pressure must both be checked. Cooling system pressure will have an effect on cooling system temperatures. For an example, look at the chart to see the effect of pressure and height above sea level on the boiling (steam) point of water.

To check the cooling system, the coolant level must be to the correct level with the engine stopped and cold.

After the engine is cool, loosen the pressure cap and let the pressure out of the cooling system. Then remove the pressure cap.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

The level of the coolant should be within 13 mm (1/2 in) below the bottom of the fill pipe or to the proper level on the sight glass, if so equipped.

Test Tools For Cooling System

The 8T0470 Thermistor Thermometer Group is used in the diagnosis of over heating (engine hotter than normal) or overcooling (engine cooler than normal) problems. This group can be used to check temperatures in several different parts of the cooling system. The testing procedure is in Special Instruction, Form No. SEHS8446.

8T0470 Thermistor Thermometer Group

The 8T2700 Blowby/Air Flow Indicator Group is used to check the air flow through the radiator core. The test procedure is in Special Instruction, Form No. SEHS8712.

8T2700 Indicator Group

The 6V3121 Multitach Group is used to check the fan speed. The testing procedure is in Special Instruction, Form No. SEHS7807.

6V3121 Multitach Group

Checking Pressure Cap

One cause for a pressure loss in the cooling system can be a defective seal on the radiator pressure cap.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

After the engine is cool, loosen the pressure cap and let the pressure out of the cooling system. Then remove the pressure cap.

Inspect the pressure cap carefully. Look for damage to the seal or to the surface that seals. Any foreign material or deposits on the cap, seal or surface that seals, must be removed.

Typical Schematic Of Pressure Cap
(A) Sealing surface of cap and radiator.

9S8140 Cooling System Pressurizing Pump Group

The 9S8140 Cooling System Pressurizing Pump Group is used to test pressure caps and to pressure check the cooling system for leaks.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

To check the pressure cap for the pressure that makes the pressure cap open, use the procedure that follows:

1. Remove the pressure cap from the radiator.

2. Put the pressure cap on the 9S8140 Cooling System Pressurizing Pump Group.

3. Look at the gauge for the exact pressure that makes the pressure cap open.

4. Make a comparison of the reading on the gauge with the correct pressure at which the pressure cap must open.

5. If the pressure cap is defective, install a new pressure cap.

Testing Radiator And Cooling System For Leaks

To test the radiator and cooling system for leaks, use the procedure that follows:

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

1. Remove the pressure cap from the radiator.

2. Make sure the coolant is over the top of the radiator core.

3. Put the 9S8140 Cooling System Pressurizing Pump Group on the radiator.

4. Get the pressure reading on the gauge to 20 kPa (3 psi) more than the pressure on the pressure cap.

5. Check the radiator for outside leakage.

6. Check all connections and hoses for the cooling system for outside leakage.

7. If you do not see any outside leakage and the pressure reading on the gauge is still the same after 5 minutes, the radiator and cooling system does not have leakage. If the reading on the gauge goes down and you do not see any leakage, there is leakage on the inside of the cooling system. Make repairs as necessary.

Water Temperature Gauge Test

Test Location
(1) Plug.

Check the accuracy of the water temperature gauge if either of the conditions that follow are found:

1. The gauge reads normal, but the engine is too hot and a loss of coolant is found.

2. The gauge shows that the engine is hot, but no loss of coolant can be found.

Remove plug (1) and install the 8T0470 Thermistor Thermometer Group or the 2F7112 Thermometer. A temperature gauge of known accuracy can also be used to make this check.

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Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury.

Start the engine and run it until the temperature reaches the desired range according to the test thermometer. If necessary, put a cover over part of the radiator or cause a restriction of the air flow. The reading on the gauge for water temperature should agree with test thermometer within the tolerance range of the gauge.

NOTE: An ECAP or DDT can also be used to check the coolant temperature of the cooling system.

Water Temperature Regulator Test

1. Remove the regulator from the engine.

2. Heat water in a pan until the temperature is 98°C (208°F). Move the water around in the pan to make it all the same temperature.

3. Hang the regulator in the pan of water. The regulator must be below the surface of the water and it must be away from the sides and bottom of the pan.

4. Keep the water at the correct temperature for 10 minutes.

5. After ten minutes, remove the regulator and immediately measure the distance the regulator has opened. The distance must be a minimum of 9.5 mm (.37 in).

6. If the distance is less than 9.5 mm (.37 in), make a replacement of the regulator.

Water Pump Pressure Check

(1) Plug. (2) Water outlet. (3) Coolant temperature sensor. (4) Water manifold assembly. (5) Temperature regulator housing. (6) Plug. (7) Bypass line. (8) Water pump. (9) Plug.

Water pump outlet pressure can be checked on water manifold assembly (4) next to the coolant temperature sensor (3). This check will determine if the water pump is operating correctly.

Remove plug (1) from water manifold assembly (4). Install the pressure gauge (9S8138) in the port and measure the pump pressure. The water pump pressure should be 100 to 125 kPa (15 to 18 psi).

Delta pressure can be measured between plug (1) on the water manifold assembly (4) and plug (9) on the inlet side of water pump (8).

Belt Tension Chart

Basic Block

Piston Rings

This engine has a top piston groove and ring of the KEYSTONE (taper) design. The 1U6431 Keystone Piston Ring Groove Gauge Group is available to check the top ring groove in the piston. For correct use of the gauge group see the instruction card that is with the gauge group.

Instructions for 1U6431 Keystone Piston Ring Groove Gauge Group

Connecting Rods and Pistons

Use a 1U9593 Cylinder Pack Removal Group with a 1U6317 Bridge, and a 1U6319 Socket to remove a cylinder pack (connecting rod and piston) from the block. Use the 1U9788 Nylon Brush, or the 1U9787 Flex (hone) for reconditioning of the cylinder liners.

Use the 1U6683 Piston Ring Expander to remove or install piston rings.

Use the 1U6684 Piston Ring Compressor to install pistons into cylinder block.

Tighten the connecting rod nuts in the step sequence that follows:

1. Put 2P2506 Thread Lubricant on bolt threads and contact surfaces of nut and cap.

2. Tighten all nuts to 130 ± 7 N·m (95 ± 5 lb ft).

3. Put a mark on each nut and end of bolt.

4. Tighten each nut an additional 60 ± 5° (1/6 turn).

The connecting rod bearings fit tightly in the bore in the rod. If bearing joints or backs are worn (fretted), check bore size. This can be an indication of wear because of a loose fit.

Connecting Rod and Main Bearings

Connecting Rod Bearings

Connecting rod bearings are available with 0.508 mm (.0200 in) and .762 mm (.0300 in) smaller inside diameter than the original size bearings. These bearings are for crankshafts that have been "ground" (made smaller than the original size).

Main Bearings

Main bearings are available with 0.508 mm (.0200 in) and .762 mm (.0300 in) smaller inside diameter than the original size bearings. These bearings are for crankshafts that have been "ground" (made smaller than the original size).

Main bearings are also available with a larger outside diameter than the original size bearings. These bearings are for cylinder blocks that have had the bore for the main bearings "bored" (made larger than the original size). The size available is 0.508 mm (.0200 in) larger outside diameter than the original size bearings.

Cylinder Block

1P3537 Dial Bore Gauge Group

The bore in the block for main bearings can be checked with the main bearing caps installed without bearings. Tighten the nuts that hold the caps to the torque shown in the Specifications. Alignment error in the bores must not be more than 0.08 mm (.003 in). Special Instruction, Form No. SMHS7606 gives instructions for the use of 1P4000 Line Boring Tool Group for alignment of the main bearing bores. The 1P3537 Dial Bore Gauge Group can be used to check the size of the bores. Special Instruction, Form No. GMG00981 is with the group.

Cylinder Liner Projection

Check cylinder liner projection above top of spacer block as follows:

1. Make certain that the cylinder liner flange and cylinder block are clean. Do not install liner seals when this check is made.

Checking Cylinder Liner Projection
(1) 2S5658 Washer. (2) 7X2558 Bolt. (3) 8F1484 Washer. (4) 7K1977 Washer. (5) Spacer block. (6) Cylinder liner. (7) Cylinder block.

2. Install washers and bolts as shown around the cylinder liner. Tighten all bolts finger tight.

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NOTICE
The 7K1977 Washer (4) must be used between the spacer block (5) and the 8F1484 Washer (3) to avoid causing damage to the spacer block.

3. Tighten the bolts evenly, in five steps; 14 N·m (10 lb ft), 25 N·m (20 lb ft), 40 N·m (30 lb ft), 55 N·m (40 lb ft) and then to 70 N·m (50 lb ft).

4. Tighten the bolts again to 70 N·m (50 lb ft).

5. Use a 8T0455 Liner Projection Tool Group to measure liner projection. Special Instruction Form No. SMHS7727 gives more information for the measurement procedures.

6. To zero the dial indicator, use the back of the 1P5507 Gauge with the dial indicator mounted in the 1P2402 Gauge Body.

7. Liner projection must be 0.040 to 0.200 mm (.0016 to .0079 in). (Make the measurement to the top of the liner flange, not the inner ring). The maximum differential between high and low measurements made at four places around each liner is 0.05 mm (.002 in). The average projection of liners next to each other must not be more than 0.05 mm (.002 in). The maximum difference in the average projection of the cylinder liners under one cylinder head must not be more than 0.10 mm (.004 in).

NOTE: If liner projection changes from point to point around the liner, turn the liner to a new position within the bore. If still not within specifications move liner to a different bore.

NOTE: When liner projection is correct, put a temporary mark on the liner and spacer block so when the seal is installed, the liner can be installed in the correct position.

Flywheel And Flywheel Housing

Face Run Out (axial eccentricity) of the Flywheel Housing

8T5096 Dial Indicator Group Installed (Typical Example)

If any method other than given here is used, always remember bearing clearance must be removed to get correct measurements.

1. Fasten a dial indicator to the flywheel so the anvil of the indicator will touch the face of the flywheel housing.

2. Put a force on the crankshaft toward the rear before the indicator is read at each point.

Checking Face Runout Of The Flywheel Housing

3. With dial indicator set at "0" (zero) at location (A), turn the flywheel and read the indicator at locations (B), (C) and (D).

4. The difference between lower and higher measurements taken at all four points must not be more than 0.38 mm (.015 in), which is the maximum permissible face run out (axial eccentricity) of the flywheel housing.

Bore Runout (radial eccentricity) of the Flywheel Housing

1. Fasten the dial indicator as shown so the anvil of the indicator will touch the bore of the flywheel housing.

2. With the dial indicator in position at (C), adjust the dial indicator to "0" (zero). Push the crankshaft up against the top of the bearing. Write the measurement for bearing clearance on line 1 in column (C) in the Chart For Dial Indicator Measurement.

8T5096 Dial Indicator Group Installed (Typical Example)

NOTE: Write the dial indicator measurements with their positive (+) and negative (-) notation (signs). This notation is necessary for making the calculations in the chart correctly.

3. Divide the measurement from Step 2 by 2. Write this number on line 1 in columns (B) & (D).

4. Turn the flywheel to put the dial indicator at (A). Adjust the dial indicator to "0" (zero).

5. Turn the flywheel counterclockwise to put the dial indicator at (B). Write the measurements in the chart.

Checking Bore Runout Of The Flywheel Housing

6. Turn the flywheel counterclockwise to put the dial indicator at (C). Write the measurement in the chart.

7. Turn the flywheel counterclockwise to put the dial indicator at (D). Write the measurement in the chart.

8. Add lines I & II by columns.

9. Subtract the smaller number from the larger number in line III in columns (B) & (D). The result is the horizontal eccentricity (out of round). Line III, column (C) is the vertical eccentricity.

10. On the graph for total eccentricity, find the point of intersection of the lines for vertical eccentricity and horizontal eccentricity.

11. If the point of intersection is in the range marked "Acceptable", the bore is in alignment. If the point of intersection is in the range marked "Not Acceptable", the flywheel housing must be changed.

Graph For Total Eccentricity

Face Runout (axial eccentricity) of the Flywheel.

1. Install the dial indicator as shown. Always put a force on the crankshaft in the same direction before the indicator is read so the crankshaft end clearance (movement) is always removed.

Checking Face Runout Of The Flywheel (Typical Example)

2. Set the dial indicator to read "0" (zero).

3. Turn the flywheel and read the indicator every 90°.

4. The difference between the lower and higher measurements taken at all four points must not be more than 0.15 mm (.006 in), which is the maximum permissible face runout (axial eccentricity) of the flywheel.

Bore Runout (radial eccentricity) of the Flywheel

1. Install the dial indicator (3) and make an adjustment of the universal attachment (4) so it makes contact as shown.

2. Set the dial indicator to read "0" (zero).

3. Turn the flywheel and read the indicator every 90°.

4. The difference between the lower and higher measurements taken at all four points must not be more than 0.15 mm (.006 in), which is the maximum permissible bore runout (radial eccentricity) of the flywheel.

5. Runout (eccentricity) of the bore for the pilot bearing for the flywheel clutch, must not exceed 0.13 mm (.005 in).

Checking Bore Runout Of The Flywheel (Typical Example) (1) 7H1945 Holding Rod. (2) 7H1645 Holding Rod. (3) 7H1942 Indicator. (4) 7H1940 Universal Attachment.

Checking Flywheel Clutch Pilot Bearing Bore

Vibration Damper

Front Of Engine
(1) Vibration damper. (2) Pulley. (3) Bolts (six).

NOTE: Bolts (3) must be tightened to a torque of 300 ± 30 N·m (220 ± 22 lb ft).

Damage to or failure of the damper will increase vibrations and result in damage of the crankshaft. It will cause more gear train noise at variable points in the speed range.

If the damper is bent or damaged, or if the bolt holes in the damper are loose fitting, replace the damper. Replacement of the damper is also needed at the time of a crankshaft failure due to torsional forces.

A used vibration damper can have a visual wobble (movement to the front and then to the rear when in rotation) on the outer ring and still not need replacement, because some wobble of the outer ring is normal. To see if the amount of wobble is acceptable, or replacement is necessary, check the damper with the procedure that follows:

1. Install a dial indicator, contact point and other parts as necessary to hold the dial indicator stationary. The contact point must be perpendicular (at 90° angle) to the face of the outer ring of the damper, and must make contact approximately at the center of the outer ring.

2. Push on the front end of the crankshaft so the end play (free movement on the centerline) is removed. Keep the crankshaft pushed back until the measurements are done.

3. Adjust the dial indicator to zero.

4. Turn the crankshaft 360° and watch the dial indicator. A total indicator reading of 0.00 to 2.03 mm (.000 to .080 in) is acceptable.

Electrical System

Test Tools For Electrical System

Most of the tests of the electrical system can be done on the engine. The wiring insulation must be in good condition, the wire and cable connections must be clean and tight, and the battery must be fully charged. If the on-engine test shows a defect in a component, remove the component for more testing.

The service manual Testing And Adjusting Electrical Components, Form No. REG00636 has complete specifications and procedures for the components of the starting circuit and the charging circuit.

4C4911 Battery Load Tester

The 4C4911 Battery Load Tester is a portable unit in a metal case for use under field conditions and high temperatures. It can be used to load test all 6, 8 and 12V batteries. This tester has two heavy-duty load cables that can easily be fastened to the battery terminals. A load adjustment knob on the top permitsthe current being drawn from the battery to be adjusted to a maximum of 100 amperes. The tester is cooled by an internal fan that is automatically activated when a load is applied.

The tester has a built in LCD digital voltmeter and amperage meter. The digital voltmeter accurately measures the battery voltage at the battery through tracer wires buried inside the load cables. The digital amperage meter accurately displays the current being drawn from the battery under test.

NOTE: Make reference to Operating Manual, Form No. SEHS9249 for more complete information for use of the 4C4911 Battery Load Tester.

6V7070 Heavy-Duty Digital Multimeter

The 6V7070 Heavy-Duty Digital Multimeter is a completely portable, hand held instrument with a digital display. This multimeter is built with extra protection against damage in field applications, and is equipped with seven functions and 29 ranges. The 6V7070 Multimeter has an instant ohms indicator that permits continuity checks for fast circuit inspection. It also can be used for troubleshooting small value capacitors.

The 6V7800 Regular-Duty Digital Multimeter (a low cost option to the Heavy-Duty Multimeter) is also available; however, the 6V7800 Multimeter does not have the 10A range or the instant ohms feature of the 6V7070 Multimeter.

NOTE: Make reference to Special Instruction Form No. SEHS7734 for more complete information for use of the 6V7070 and 6V7800 Multimeters.

Battery

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Never disconnect any charging unit circuit or battery circuit cable from battery when the charging unit is operated. A spark can cause an explosion from the flammable vapor mixture of hydrogen and oxygen that is released from the electrolyte through the battery outlets. Injury to personnel can be the result.

Before any testing is done on the electrical system, the batteries should be checked for good connections and must be at least 75% (1.225 Sp Gr) fully charged.

The battery circuit is an electrical load on the charging unit. The load is variable because of the condition of the charge in the battery. Damage to the charging unit will result if the connections (either positive or negative) between the battery and charging unit are broken while the charging unit is in operation. This is because the battery load is lost and there is an increase in charging voltage. High voltage will damage, not only the charging unit, but also the regulator and other electrical components.

Use the 4C4911 Battery Load Tester to load test a battery that does not hold a charge when in use. Refer to Operating Manual, Form No. SEHS9249 for more detailed instructions on use of the 4C4911 Battery Load Tester. See Special Instruction, Form No. SEHS7633 for the correct procedure and specifications to use when testing batteries.

Charging System

The condition of charge in the battery at each regular inspection will show if the charging system operates correctly. An adjustment is necessary when the battery is constantly in a low condition of charge or a large amount of water is needed (more than one ounce of water per cell per week or per every 100 service hours).

When it is possible, make a test of the charging unit and voltage regulator on the engine, and use wiring and components that are a permanent part of the system. Off-engine (bench) testing will give a test of the charging unit and voltage regulator operation. This testing will give an indication of needed repair. After repairs are made, again make a test to give proof that the units are repaired to their original condition of operation.

To check for correct output of the alternator, see the Specifications module.

For complete service information, refer to Service Manual Module, Form No. SENR3862, Delco Remy 27-SI Series Alternators. This module is part of REG00636 Service Manual.

Before the start of on-engine testing, the charging system and battery must be checked as shown in the Steps that follow:

1. Battery must be at least 75% (1.225 Sp. Gr.) fully charged and held tightly in place. The Battery holder must not put too much stress on the battery.

2. Cables between the battery, starter and engine ground must be the correct size. Wires and cables must be free of corrosion and have cable support clamps to prevent stress on battery connections (terminals).

3. Leads, junctions, switches, and panel instruments that have direct relation to the charging circuit must give correct circuit control.

4. Inspect the drive components for the charging unit to be sure they are free of grease and oil and have the ability to operate the charging unit.

Alternator Regulator Adjustment (Delco-Remy)

When an alternator is charging the battery too much or not enough, the charging rate of the alternator should be checked. Make reference to the Specifications module to find all testing specifications for the alternators and regulators.

Alternator
(1) Ground terminal. (2) Pulley nut.

No adjustment can be made to change the rate of charge on the alternator regulators. If rate of charge is not correct, a replacement of the regulator is necessary.

Alternator Pulley Nut Tightening (Delco-Remy)

Tools To Tighten Alternator Pulley Nut
(1) 8T9293 Torque Wrench. (2) 8S1588 Adapter (1/2" female to 3/8" male). (3) 2P8267 Socket Assembly. (4) 8H8517 Combination Wrench (1-1/8"). (5) 8T5314 Socket.

Tighten nut that holds the pulley to a torque of 100 ± 7 N·m (75 ± 5 lb ft) with the tools shown.

Starting System

Use the multimeter in the DCV range to find starting system components which do not function.

Move the start control switch to activate the starter solenoid. Starter solenoid operation can be heard as the pinion of the starter motor is engaged with the ring gear on the engine flywheel.

If the solenoid for the starter motor will not operate, it is possible that the current from the battery did not get to the solenoid. Fasten one lead of the multimeter to the connection (terminal) for the battery cable on the solenoid. Put the other lead to a good ground. A zero reading is an indication that there is a broken circuit from the battery. More testing is necessary when there is a voltage reading on the multimeter.

The solenoid operation also closes the electric circuit to the motor. Connect one lead of the multimeter to the solenoid connection (terminal) that is fastened to the motor. Put the other lead to a good ground. Activate the starter solenoid and look at the multimeter. A reading of battery voltage shows the problem is in the motor. The motor must be removed for further testing. A zero reading on the multimeter shows that the solenoid contacts do not close. This is an indication of the need for repair to the solenoid or an adjustment to be made to the starter pinion clearance.

Make a test with one multimeter lead fastened to the connection (terminal) for the small wire at the solenoid and the other lead to the ground. Look at the multimeter and activate the starter solenoid. A voltage reading shows that the problem is in the solenoid. A zero reading is an indication that the problem is in the start switch or the wires for the start switch.

Fasten one multimeter lead to the start switch at the connection (terminal) for the wire from the battery. Fasten the other lead to a good ground. A zero reading indicates a broken circuit from the battery. Make a check of the circuit breaker and wiring. If there is a voltage reading, the problem is in the start switch or in the wires for the start switch.

A starter motor that operates too slow can have an overload because of too much friction in the engine being started. Slow operation of the starter motor can also be caused by a short circuit, loose connections and/or dirt in the motor.

To check for correct output of starter motors and starter solenoid, see the Specifications module.

For complete service information, refer to Service Manual Module, Form No. SENR3581, Delco Remy 37-MT/42-MT Series Starting Motors. This module is part of REG00636 Service Manual.

Pinion Clearance Adjustment (Delco-Remy)

When the solenoid is installed, make an adjustment of the pinion clearance. The adjustment can be made with the starter motor removed.

Typical Connection for Checking Pinion Clearance
(1) Connector from MOTOR terminal on solenoid to motor. (2) SW terminal (3) Ground terminal.

1. With the solenoid installed on the starter motor, remove connector (1).

2. Connect a battery, of the same voltage as the solenoid, to the terminal (2), marked SW.

3. Connect the other side of the battery to ground terminal (3).

4. Connect for a moment a wire from the solenoid connection (terminal) marked MOTOR to the ground connection (terminal). The pinion will shift to crank position and will stay there until the battery is disconnected.

Typical Pinion Clearance Adjustment
(4) Shaft nut. (5) Pinion. (6) Pinion clearance.

5. Push the pinion toward the commutator end to remove free movement.

6. Pinion clearance (6) must be 8.3 to 9.9 mm (.33 to .39 in).

7. To adjust pinion clearance, remove plug and turn nut (4).

8. After the adjustment is completed, install the plug over adjustment nut (4) and install connector (1) between the MOTOR terminal on the solenoid and the starter motor.