- 1. Engine Fails to Start
- 2. Misfiring
- 3. Stalls at Low Speed
- 4. Erratic Engine Speed
- 5. Low Power
- 6. Excessive Vibration
- 7. Heavy Combustion Knock
- 8. Valve Train Clicking Noise
- 9. Oil in Coolant
- 10. Mechanical Knock
- 11. Excessive Fuel Consumption
- 12. Loud Valve Train Noise
- 13. Little Rocker Arm Movement and Excessive Valve Lash
- 14. Valve Rotocoil or Spring Retainer Free
- 15. Slobber
- 16. Valve Lash Close-up
- 17. Premature Engine Wear
- 18. Coolant in Engine Lubricating Oil
- 19. Excessive Black or Gray Smoke
- 20. Excessive White or Blue Smoke
- 21. Low Engine Oil Pressure
- 22. High Lubricating Oil Consumption
- 23. Abnormal Engine Coolant Temperature
- 24. Starting Motor Fails to Crank
- 25. Alternator Fails to Charge
- 26. Alternator Charging Rate Low or Unsteady
- 27. Alternator Charging Rate Excessive
- 28. Noisy Alternator
- 2. Misfiring
Difficulty within the fuel system can be classed in one of two groups: lack of fuel or too much fuel for proper combustion.
Many times the fuel system is blamed when the fault lies elsewhere, especially when smoky exhaust is the problem. Smoky exhaust can be the result of a faulty fuel injection valve, but it can also be caused by lack of air for complete combustion, overloading at high altitude, excessive oil burning or lack of compression.
1. Observe the fuel pressure gauge reading. Lack of pressure indicates difficulty in the supply side of the system.
2. Check the fuel level in the supply tank and the fuel tank cap vent for being plugged.
3. See that the vent valve is closed.
4. Check for leakage in the fuel supply lines and components or for a kinked or restricted supply line.
5. Replace the fuel filter element and clean the primary fuel filter if so equipped.
6. Inspect the fuel bypass valve to see that it moves freely and that dirt is not holding the plunger off its seat. Be certain the spring has correct tension.
7. Bleed the fuel system to remove trapped air.
Testing Fuel Injection Equipment
A simple check can be made to determine which cylinder is misfiring or causes puffing black smoke. With the engine running at a speed which makes the defect most pronounced, momentarily loosen the fuel line nut on an injection pump sufficiently to "cut out" the cylinder. Check each cylinder in the same manner. If one is found where loosening makes no difference in the irregular operation or causes puffing black smoke to cease, the pump and valve for only that cylinder need be tested.
Checking Fuel Injection Valve
Examine fuel injection valves for:
- 1. Excessive carbon on tip of nozzle or in orifice.
- 2. Erosion of the orifice.
- 3. Screen plugged with dirt.
- 2. Erosion of the orifice.
The condition of a capsule-type nozzle assembly can be tested on the Caterpillar Diesel Fuel Injection Test Bench, and the rate of leakage of the nozzle assembly can be determined.
Checking Fuel Injection Pump Lifter Washer and Pump Plunger
The timing dimension should be checked and adjusted, if necessary, by setting the fuel injection pump timing dimension with the fuel injection pump off the engine. This will assure that the point of the fuel injection is correct. If the timing dimension is too small, injection will begin early, and if too great, injection will be late.
When pump plunger wear becomes excessive, the lifter washer may also be worn so it will not make full contact with the end of a new plunger. To avoid rapid wear on the end of the new plunger, replace the lifters having washers showing visible wear.
WEAR BETWEEN LIFTER WASHER AND PLUNGER
Fig. A illustrates the contact surfaces of a new pump plunger and a new lifter washer. In Fig. B the pump plunger and lifter washer have worn considerably. Fig. C shows how the flat end of a new plunger makes poor contact with a worn lifter washer, resulting in rapid wear to both parts.
A pump can maintain a satisfactory discharge rate and yet be unserviceable because of delayed timing resulting from wear on the lower end of the plunger. When testing a pump which has been in use for a long time, check the plunger length with a micrometer. Discard the pump if the plunger measures less than the minimum length (worn) dimension.
Inspect the upper diameter of the plunger for wear. Performance of pumps worn in this manner can be checked as described in the Instructions for Fuel Injection Test Bench.
Fuel Injection Service
Fuel Injection Valve
When installing a fuel injection valve, always check the seats of both the nozzle and the precombustion chamber. The nozzle assembly should be only finger-tight on the body. It is important to maintain the nozzle retaining nut torque to 105 ± 5 lb. ft. (14.5 ± 0.7 mkg). EXCESSIVE TORQUE will damage the nozzle. LESS TORQUE will allow the nozzle to leak and may cause the nozzle case to bulge or split.
Fuel Injection Pump
When removing fuel injection pumps, spacers and lifters the components should be kept together and marked so they can be installed in their respective locations.
While disassembling fuel injection pumps, exercise considerable care to prevent damage to the plunger surfaces. The barrel and the plunger are matched and are not interchangeable. Use extreme care when inserting the plunger into the bore of the barrel.
Fuel Injection Pump Installation
The installation of fuel injection pumps requires that the lifter be at a low point and the fuel rack be centered or at "zero" position. To center or "zero" the rack, install the 7S7113 Rack Setting Gauge and set it at .000 in., retract the speed limiter, and move the rack in "fuel on" direction until it contacts the gauge. To install the pump, sight down the pump and align notches in bonnet and barrel with slot in the pump gear segment. Slot is 180° from pump gear segment center tooth.
RACK SETTING GAUGE INSTALLED
1. 7S7113 Rack Setting Gauge. A. 9S240 Rack Positioning Tool Group can also be used.
Position the notches in bonnet and barrel to align with dowels in the housing. Install the pump. Keep a downward force (by hand) on the pump and install the bushing finger tight, until flush with top of housing. If the bushing cannot be assembled this far finger tight, remove the bushing and pump. The threads, on the bushing or in the housing, can be the restriction. Align the pump components and reinstall it. If the bushing installs correctly, tighten it to a torque of 150 ± 10 lb. ft. (20.7 ± 1.4 mkg). Overtightening the bushing can damage the housing or if the bushing is not tight enough, the pump will leak.
Total rack travel, approximately .800 in. (20.32 mm), will be reduced if the pump is installed one or more teeth off in either the "fuel on" or "fuel off" side of its gear segment. The only way to check for correct installation of pumps with engine stopped is to measure full rack travel with the entire governor removed, including piston and valve mechanism.
Fuel Injection Lines
Fuel from the fuel injection pumps is sent through the fuel injection lines to the fuel injection valves.
Each fuel injection line of an engine has a special design and must be installed in a certain location. When fuel injection lines are removed from an engine, put identification marks or tags on the fuel lines as they are removed, so they can be put in the correct location when they are installed.
TIGHTENING THE NUT OF A FUEL INJECTION LINE
1. 5P144 Fuel Line Socket.
The nuts that hold a fuel injection line to an injection valve and injection pump must be kept tight. Use a torque wrench and the 5P144 Fuel Line Socket (1) to tighten the fuel line nuts to 30 ± 5 lb. ft. (4.1 ± 0.7 mkg).
Fuel Bypass Valve
The fuel bypass valve should control fuel pressure to the fuel injection pump at full speed to a pressure of 25 to 32 psi (1.8 to 2.2 kg/cm2).
Locating Top Center Compression Position For No.1 Piston
No.1 piston on the compression stroke at top center (TC) is the reference point for all timing procedures.
LOCATING TOP CENTER
1. Timing pointer (aligned with mark on flywheel).
Remove the valve and rocker arm cover (the two valves at the front of the engine are the intake and exhaust valves for No.1 cylinder). Remove the plate on the left of the flywheel housing.
Rotate the crankshaft counterclockwise (as viewed from the flywheel end) at least 60°, until both the intake and exhaust valves of No.1 cylinder are closed.
Align the timing mark "TC 1" with the pointer (1). The No.1 piston is now positioned at top center (TC) on compression.
Fuel System Adjustments
Checking Fuel Injection Pump Timing: On Engine
The timing dimension should be checked and reset, if necessary, to account for slipped accessory drive shaft coupling or worn timing gears. The timing dimension can be checked in either of the following manners.
Checking with 1P540 Flow Checking Tool Group and 3S2954 Timing Indicator Group
Before performing flow check, locate (TC) compression position for No.1 piston.
Refer to Special Instruction (FM035709) for complete and detailed instructions for the fuel flow method of engine timing.
Travel of piston (6), from point of closing inlet port (5) to top center, can be found by using the 3S2954 Timing Indicator Group. Convert the travel of piston (6) into degrees to determine if engine timing is correct.
The 1P540 Flow Checking Tool Group is used to pressurize the fuel system. Maintain 10 to 15 psi (0.7 to 1.1 kg/cm2) fuel with the 1P539 Tank Assembly. This can be done with hand pump provided with the tank assembly or connecting shop air to the tank assembly.
Consult the chart to find the angle corresponding to the indicator reading. At the indicator reading and timing angle specified, fuel flow from the injection pump should be reduced to 6 to 12 drops per minute [point of closing inlet port (5)].
- 8S4618 Fuel Pump Lifter Gauge or8S4620 Fuel Pump Lifter Gauge,8S5417 Timing Fixture Plate, 8S4613 Wrench, 8S2244 Extractor
1. Locate (TC) compression position for No. 1 piston.
3. With gauge seated in fuel pump housing, the higher step of the plunger (2) must be slightly above the top surface of the gauge body (3). The lower step of the plunger must be just below the top surface of the gauge body.
FUEL PUMP LIFTER GAUGE INSTALLED
1. Fuel pump lifter gauge. 2. Plunger. 3. Body. 4. Fuel pump bore.
NOTE: If plunger (2) of gauge (1) is in the position as stated in Step 3, rotate the crankshaft in the direction of normal rotation and observe the movement of plunger (2). Plunger (2) must rise. If plunger (2) does not rise, refer to ACCESSORY DRIVE SHAFT TIMING.
4. If the plunger in the gauge is not in the position stated in Step 3, check the accessory drive shaft timing. See the topic ACCESSORY DRIVE SHAFT TIMING.
5. If the accessory drive shaft timing is correct and the lifter gauge plunger was not in the position stated in Step 3, the pump timing dimension setting must be corrected. See FUEL INJECTION PUMP TIMING DIMENSION SETTING: OFF ENGINE.
Checking with 8S7167 Gauge
- 8S7167 Gauge,6F6922 Depth Micrometer, 4 to 5 in. (101.6 to 127.0 mm) rod,8S4613 Wrench, 8S2244 Extractor.
1. Locate (TC) compression position for No.1 piston.
3. The correct timing dimension setting using depth micrometer (1) is:
Four cylinder: 4.2216 ± .0020 in. (107.229 ± 0.051 mm).
Six cylinder: 4.2179 ± .0020 in. (107.135 ± 0.051 mm).
4. If the timing dimension setting measurement is not correct, check the accessory drive shaft timing. See ACCESSORY DRIVE SHAFT TIMING.
5. If the accessory drive shaft timing is correct and the timing dimension setting measurement was incorrect, the timing setting must be corrected. See FUEL INJECTION PUMP TIMING DIMENSION SETTING: OFF ENGINE.
Fuel Injection Pump Timing Dimension Setting: Off Engine
- 1F8747 Timing Plate, 8S7167 Gauge,8S4613 Wrench and 8S2244 Extractor6F6922 Depth Micrometer, 4 to 5 in. (101.6 to 127.0 mm) rod.
NOTE: The 1P5600 Timing Fixture Group can also be used. Form GMG00838 provides detailed instructions.
The off engine method will result in correct fuel injection timing only if the pump housing is installed on a new engine or an engine with new timing gears, accessory drive shaft and fuel pump camshaft. The off engine setting adjusts for wear in the fuel injection pump housing only. The accessory drive shaft timing adjusts for wear in the timing gears, accessory drive shaft and fuel pump camshaft coupling.
1. Install the pointer assembly on the fuel injection pump housing.
2. Place 1F8747 Timing Plate on the drive end of the camshaft. Secure the plate to the camshaft.
3. Refer to the chart and select the timing plate degree setting for the lifter being checked or set. Set the timing plate by rotating it counterclockwise until the proper degree setting aligns with the pointer assembly. Lock in position with the lockscrew.
4. The fuel injection pump timing dimension (off engine), using the 8S7167 Gauge is 4.2675 ± .0020 in. (108.395 ± 0.051 mm).
5. The spacer must be changed to change the timing dimension.
6. If all timing dimensions are to be checked or reset, continue the same procedure in the firing order of the engine. Recheck each timing dimension after the adjustment has been made.
NOTE: The accessory drive shaft must be positioned correctly in relation to the engine crankshaft, before the fuel injection pump housing is installed.
Accessory Drive Shaft Timing (D330C and D333C)
- 8S5417 Timing Fixture Plate,8S5132 Puller Plate,8S8375 Sleeve,8S5133 Expansion Plug,8S6470 Pressure Screw,8B7561 Step Plate.
1. Remove the fuel injection pump housing and position the engine crankshaft so No.1 piston is on the compression stroke at top center (TC).
8S5417 TIMING FIXTURE PLATE INSTALLED
2. Install the 8S5417 Timing Fixture Plate on the rear face of the accessory drive housing, dowels aligned and bolts installed as illustrated.
NOTE: If the timing fixture plate can be installed, timing is correct. If it cannot be installed, proceed as follows:
3. Remove the small cover from the front of the timing gear housing. Remove the gear retaining nut and washer.
4. Separate the gear from the accessory drive shaft.
5. Rotate the accessory drive shaft in the direction necessary to install the 8S5417 Timing Fixture Plate.
ROTATING THE ACCESSORY DRIVE SHAFT
6. Install the conical washer, with the large diameter against the timing gear, and install the gear retaining nut. Tighten the gear retaining nut to 100 ± 10 lb. ft. (13.8 ± 1.4 mkg) and remove the timing plate. The fuel injection pump camshaft will be in time with the engine crankshaft when the injection pump housing is installed on the engine.
Accessory Drive Shaft Timing (3304 and 3306)
- 8S5417 Timing Fixture Plate,8S2264 Puller Group,8S8375 Sleeve,8B7561 Step Plate,two 3/8 in. 24-NF Bolts,3.50 in. (88.9 mm) long and two flat washers.
1. Put No.1 piston at top center (TC) on the compression position. Make reference to FINDING TOP CENTER COMPRESSION POSITION FOR NO.1 PISTON.
2. Remove the injection pump housing from the engine.
3. Install the 8S5417 Timing Fixture Plate on the rear face of the accessory housing, dowels aligned and bolts installed as illustrated.
8S5417 TIMING FIXTURE PLATE INSTALLED
NOTE: If the timing fixture plate can be installed, the timing is correct. If the timing fixture plate can not be installed, use the following procedure.
4. Remove cover (1).
REMOVAL OF COVER
5. Remove the nut and washer that hold the accessory drive gear on the accessory drive shaft.
6. Use the tools as illustrated and make the accessory drive gear loose on the accessory drive shaft.
7. Remove the puller tools and turn the accessory drive shaft in the direction necessary to install the 8S5417 Timing Fixture Plate.
TURNING THE ACCESSORY DRIVE SHAFT
8. With the 8S5417 Timing Fixture Plate installed correctly, put the washer on the accessory drive shaft with the large diameter against the gear. Install the nut and tighten the nut to 100 ± 10 lb. ft. (13.8 ± 1.4 mkg).
9. Remove the 8S5417 Timing Fixture Plate and install cover (1).
10. Turn the camshaft of the injection pump so it is in alignment with the end of the accessory drive shaft. Install the injection pump housing on the engine. Make all necessary connections and installation of components that were removed or disconnected.
11. The injection pump camshaft is now timed to No.1 cylinder.
Fuel Rack Setting
Rack Positioning Tool, Dial Indicator and Circuit Tester Method:
- 9S240 Rack Positioning Tool Group and 4B9820 Wrench.
The 9S7350 Rack Positioning Bracket Group makes it possible to set the rack, or measure rack position, during normal operation of the engine. The ability to observe rack position during operation, can provide most of the needed data to determine actual horsepower output and diagnose the cause for lack of power.
Do not attempt to adjust rack setting with engine running. Always shut down the engine before adjusting rack setting.
1. Refer to the RACK SETTING INFORMATION to obtain the correct rack setting dimension.
2. Disconnect the governor control linkage, at the most convenient location, so the governor control lever moves freely throughout its entire length of travel.
3. Remove the fuel ratio control from the rear of the governor and/or the rear cover, then remove the fuel rack cover and gasket from the front of the flange of the accessory drive housing.
4. Install rack positioning bracket group and dial indicator, over the opening for fuel rack cover on front flange of accessory drive housing.
5. Place the spacer (6) over the rod in the bracket. Adjust the dial on the indicator to read zero when the hole attachment is against the rod and the rod is against the spacer.
6. Before starting the engine, be sure the rack moves freely throughout its entire length of travel. The speed limiter will restrict rack travel until the engine is operating with proper oil pressure, or the plunger is manually depressed.
Typical example of manually depressing speed limiter plunger with rod (3) through opening in plug (2) in opening in bottom of governor housing.
7. Attach one end of the 8S4627 Circuit Tester to the brass screw terminal on the outside of the governor housing.
8. With the speed limiter depressed, rotate the governor control lever toward the fuel-on direction until the tester light comes on bright.
9. Slowly, rotate the governor control lever toward the shutoff position until the light goes out.
10. Now, again slowly rotate the governor control lever toward the fuel-on position, until the tester light just barely comes on (a dim light); rack collar is now just touching the stop bar or torque spring. Rack setting can now be read directly from the 9S215 Dial Indicator.
DIAL INDICATOR ADJUSTED TO ZERO READING (Typical Example)
6. Spacer. 7. Hole attachment.
11. To adjust rack setting, stop the engine and loosen lock nut (9). Using wrench (10) adjust screw (8) to obtain the correct rack setting. Rack travel can be read directly on the 9S215 Dial Indicator.
NOTE: Turn screw (8) clockwise to decrease rack travel. Never adjust rack travel by adding or removing shims.
12. After the rack has been adjusted, tighten lock nut (9) to 11 ± 1 lb. ft. (1.5 ± 0.14 mkg).
ADJUSTING RACK SETTING (Typical Example)
8. Adjusting screw. 9. Lock nut. 10. 4B9820 Wrench.
Rack Setting Gauge Method:
- 7S7113 Rack Setting Gauge.8S4627 Circuit Tester.FT960 Adapter Assembly (for off engine rack setting).
Use a 7S7113 Rack Setting Gauge to check the fuel rack setting. The fuel rack can be checked and adjusted with the fuel injection pump housing either installed, or removed from the engine.
1. Remove the rack cover from the front of the accessory drive housing rear flange and the cover from the rear of the governor housing.
1. 7S7113 Rack Setting Gauge.
2. Install the 7S7113 Rack Setting Gauge over the front end of the fuel rack.
3. Set gauge to the proper rack setting. Refer to the RACK SETTING INFORMATION for correct setting.
4. To adjust the rack, refer to the topic RACK POSITIONING TOOL, DIAL INDICATOR AND CIRCUIT TESTER METHOD and follow Steps 7 through 12.
NOTE: If the fuel injection pump housing is removed from the engine the fuel rack setting can be checked with 7S7113 Rack Setting Gauge but, FT960 Adapter Assembly must also be used.
Only competent personnel should attempt to adjust the low and high idle rpm. The low and high idle rpm, and the rack setting dimensions for this engine, are listed in the RACK SETTING INFORMATION.
Engine rpm should be checked with an accurate tachometer.
Low and high idle rpm can be adjusted by removing the cover at the rear of the governor, and turning the high idle and low idle adjusting screws. Turning either adjusting screw in a clockwise direction will decrease the respective high and low idle rpm. The retainer holes in the cover are shaped to prevent the screws from turning, after the adjustment has been made.
1. Cover. 2. Retainer holes (two). 3. High idle adjusting screw. 4. Low idle adjusting screw.
After setting the idle rpm, move the governor control lever to change the engine rpm. Return it to the idle position and recheck the idle rpm. Repeat the adjustment procedure until the specified idle rpm is obtained.
Fuel Ratio Control Setting
- 9S240 Rack Positioning Tool Group,4B9820 Wrench.
The fuel rack must be set correctly before setting the fuel ratio control.
1. Remove the rack cover from the front of the fuel injection pump housing, and cover (4) from the rear of the fuel ratio control.
2. Engage slot in cover (4) with cross-dowel in adjusting bolt and turn the adjusting bolt in as far as possible. This prevents the head of the bolt from limiting the travel of the fuel rack.
3. Install 9S7350 Rack Positioning Bracket Group over the front end of the fuel rack and 9S215 Dial Indicator in the bracket.
4. Remove the plug from the bottom of the governor and install plug (2). Through opening in plug (2) use rod (3) to push in (retract) the speed limiter plunger. Tighten plug (2) just enough to hold rod (3) in place (speed limiter depressed).
5. Center the rack and set the dial indicator on zero. Remove the spacer.
6. With the speed limiter plunger held in, move governor control lever (1) to FULL LOAD position. Hold the lever in the FULL LOAD position while making the adjustment.
7. Turn adjusting bolt out with cover (4) until the proper dial indicator reading is obtained. The proper reading is listed in the RACK SETTING INFORMATION.
8. Turn cover (4) clockwise the amount necessary to align the bolt holes and install cover (4).
SETTING FUEL RATIO CONTROL
9. Remove the 9S7350 Rack Positioning Bracket Group, 9S215 Dial Indicator and install the rack cover.
10. Install the standard plug in place of plug (2).
NOTE: Before starting the engine, make certain the governor control lever will move the governor to the SHUTOFF position and that all parts operate freely.
With the above initial adjustment made, a further adjustment while the engine is running can be made if necessary to improve engine performance. To reduce exhaust smoke during acceleration, turn cover' (4) out (less fuel) 1/2 turn at a time until satisfactory. When exhaust smoke is acceptable but acceleration is sluggish, turn cover (4) in (more fuel) 1/2 turn at a time until satisfactory.
NOTE: Some exhaust smoke is likely to appear at maximum acceleration.
NOTE: If acceleration is sluggish and full engine power seems to be lost, inspect the air line to the cover and the cover gasket for air leaks. If no air leaks are apparent, inspect the diaphragm. A damaged diaphragm will not allow the fuel rack to open completely, acceleration will be sluggish and full engine power cannot be obtained.
Air Induction And Exhaust System
Restriction Of Air Inlet And Exhaust
Engine horsepower and efficiency will be reduced if either the air inlet or exhaust system becomes restricted. The air cleaner should not restrict air flow to the point of 30" (762 mm) of water difference in pressure.
Exhaust back pressure (pressure difference measured between the turbocharger outlet elbow tap and the ambient air) should be no more than that shown in the chart.
Measuring Inlet Manifold Pressure: Turbocharged Engines
When an engine is suspected of lacking power, it is sometimes desirable to make a quick instrument check to determine the horsepower.
By checking inlet manifold pressure, and comparing that pressure with the RACK SETTING INFORMATION, one can determine if an engine is operating efficiently. This test should be used if engine horsepower seems to be too low, yet no specific symptom of engine trouble is apparent.
Inlet manifold pressures in the RACK SETTING INFORMATION are recorded under specific operating conditions: 29.4 inches (746.76 mm) of mercury barometric pressure, 85°F. (29°C.) ambient temperature and 35 API rated fuel. Any deviation from these conditions can affect the inlet manifold pressure. Ambient air which is denser than that at 85°F./29.4 inches (29°C./746.76 mm) of mercury, can cause a slightly higher horsepower and inlet manifold pressure reading than listed in the RACK SETTING INFORMATION. If the ambient air is less dense, the horsepower and inlet manifold pressure rating can be slightly lower than the values given in the RACK SETTING INFORMATION. Fuel density (API gravity rating) also affects the horsepower and inlet manifold pressure. If the fuel is rated above the standard 35 API gravity rating, the inlet manifold pressure can be slightly less than the value given in the RACK SETTING INFORMATION. If the fuel is rated below the standard rating, the inlet manifold pressure can be slightly more. BE SURE THE AIR INLET AND EXHAUST ARE NOT RESTRICTED WHEN CHECKING INLET MANIFOLD PRESSURE.
The components in a 4S6553 Instrument Group provide a means of reading engine rpm and inlet manifold pressure simultaneously. This group contains an instantaneous reading tachometer and a gauge for reading inlet manifold pressure. Special Instruction (FE036044) included with this group, explain the testing procedure.
Checking Inlet Manifold Pressure At Engine Full Load And Speed
- 4S6553 Instrument Group.
Checking inlet manifold pressure (frequently referred to as "boost") at engine FULL LOAD and speed (governor balance point), provides a convenient test of engine performance. To check inlet manifold pressure, some method of controlling the load on the engine must be provided. The preferred method is by using a dynamometer.
Using the 4S6553 Instrument Group, proceed as follows:
1. Connect the manifold pressure gauge to the inlet manifold.
MANIFOLD PRESSURE TAP (Typical Example)
1. Location to check inlet manifold pressure.
2. Connect the tachometer to the engine to locate the full load rpm (governor balance point).
NOTE: At the balance point, rack position and the injection pump speeds are such that maximum fuel is delivered to the engine, turbocharger speed is maximum, and inlet manifold pressure is maximum.
3. With the governor control moved to FULL LOAD position, load the engine until rpm stabilizes. Slowly decrease the load (allowing engine rpm to increase) while simultaneously observing the rise in inlet manifold pressure.
NOTE: Inlet manifold pressure will rise (as load is decreased), reach a peak, and fall sharply. Watch for the pressure peak and note the rpm at which it occurs. This rpm is the governor balance point.
4. Record the engine rpm and inlet manifold pressure.
5. Return governor control to LOW IDLE.
6. Compare the recorded information, engine rpm and inlet manifold pressure, with the values listed in the RACK SETTING INFORMATION.
7. If full load rpm and/or inlet manifold pressure are outside their limits, determine the cause and correct. See topic PROBLEM SOLVING.
8. If stall speed is within limits, but boost is not, determine why and correct.
9. If boost and/or stall speed are outside their limits, determine cause as either a converter or engine malfunction and correct.
Excessive crankcase pressure can be a result of combustion gas leaking past broken or damaged pistons and/or piston rings. This condition will usually be accompanied by irregular engine operation and excess fumes from crankcase breather opening. This pressure can cause the breather element to become restricted in an unusually short time. In addition, it can cause engine oil to leak past gaskets and seals that would function properly under normal conditions.
Irregular (rough) engine operation can be caused by improperly adjusted or leaky valves. Operate the engine at rpm which makes the malfunction most pronounced. A non-firing or low compression cylinder can be located by momentarily loosening and then retightening fuel lines at the fuel injection pumps one at a time. Continue this until a loosened fuel injection line makes little or no difference in the engine operation. This same test can also indicate faulty fuel injection so further checking of the cylinder is necessary.
The preceding test is merely a quick means of pinpointing the source of cylinder compression loss. Removal of the head and visual inspection of the valves and seats is necessary to check for minor valve defects which do not have much effect on engine operation. This is usually done during general engine reconditioning.
The following procedure provides a more complete check of the sealing ability of the individual valves without removing the cylinder head:
1. Remove the fuel injection nozzle, leaving the precombustion chamber in place.
2. Adapt an air hose to the precombustion chamber. This can be done with either a threaded fitting or by holding a rubber adapter in place.
3. Rotate the crankshaft until the piston in the suspected cylinder is at top center (TC) on the compression stroke. In this position the valves of the cylinder are closed.
4. Force air into the cylinder and then check for escaping air. Air escaping from the exhaust opening indicates exhaust valve leakage. Air escaping from the air cleaner inlet indicates inlet valve leakage. If air escapes from the crankcase breather during this test, the piston, rings and/or liner can be at fault.
On turbocharged engines, it may be necessary to remove inlet and outlet connections on both sides of turbocharger to notice leakage.
- 3B7762 Tee3B7767 Nipple6K5875 Hose Assembly8M2744 Gauge1P5569 Tip7S8890 Adapter7S8895 Adapter8S2268 Tube Assembly9S7341 AdapterAir pressure regulator
Engine cylinder condition can be analyzed with controlled pressure air through the engine cylinder precombustion chamber. Special Instruction (GMG00694) explains the procedure.
Air escaping from the exhaust opening indicates exhaust valve leakage. Air escaping from the air inlet indicates inlet valve leakage. If air escapes from the crankcase breather during this test, it is an indication of piston, rings and/or liner faults.
MEASURING AIR FLOW
1. Air regulator. 2. 6K6875 Hose Assembly and 7S8895 Adapter. 3. 8S2268 Tube Assembly and 9S7341 Adapter. 4. 8M2744 Gauge (0 to 100 psi). 5. 7S8890 Adapter. Parts not shown: 3B7762 Tee, 3B7767 Nipple, 1P5569 Tip.
Original equipment cylinder heads for turbocharged engines are equipped with valve seat inserts, and naturally aspirated engines without inserts. Valve seat inserts are installed in replacement cylinder heads for all engines.
Tools required to remove valve seat inserts are in the 9S3080 Valve Insert Puller Group.
Valve Clearance Setting
Refer to the Lubrication and Maintenance Procedures for details of valve clearance adjustment.
Precombustion Chamber Position
PRECOMBUSTION CHAMBER POSITIONING DIAGRAM
1. Center line of engine. 2. Center line of cylinder. A. "Go" range. B. Intermediate gasket range. C. Thickest gasket range.
Install thinnest gasket first. Install precombustion chamber and tighten to 150 ± 10 lb. ft. (21.7 ± 1.4 mkg). If the glow plug opening is not positioned in the (A) range, remove the chamber. If the glow plug opening is in the (B) range use the intermediate gasket. If the glow plug opening is in the (C) range use the thickest gasket.
Use gaskets to position precombustion chambers to prevent wiring interference by using the proper gasket.
Apply 9M3710 Anti-Seize Compound to glow plug threads before installing. Tighten glow plugs to 120 ± 24 lb. in. (138.4 ± 27.6 cm.kg).
Engine lubrication system problems are usually indicated by one of these four symptoms:
EXCESSIVE OIL CONSUMPTION
LOW OIL PRESSURE
HIGH OIL PRESSURE
UNUSUAL BEARING WEAR
Excessive Oil Consumption
Check crankshaft seals for leakage at both ends of the engine, look for leaks around the oil pan gasket and all lubrication system connections. Check to see if oil is being blown from the crankcase breather. This can be caused by combustion gases leaking past pistons. Clogged crankcase breathers will contribute to high crankcase pressure and result in gasket and seal leaks.
On turbocharged engines, leaking turbocharger shaft seals (turbine end) will cause loss of oil through the exhaust gases.
Internal Leakage Into Upper Cylinders
Upper cylinder oil leakage can be the cause of blue smoke. There are four possible routes for oil leakage into upper cylinders:
Oil can leak past the ring seals at the impeller end of the turbocharger shaft.
Leakage between worn guides and valves is also possible.
Worn or damaged piston rings or plugged oil return holes can cause oil to enter the upper cylinder. Incorrectly installed compression rings will cause oil to pump into the cylinders.
Excess oil usage can also be the result of oil viscosity being too low for prevailing conditions. Low oil viscosity can be caused by crankcase dilution, incorrect selection of oil weights, or engine overheating.
Low Oil Pressure
Oil Pressure Gauge
A defective oil pressure gauge may show low oil pressure.
Crankcase Lubricant Level
Oil level can be too low for oil pump suction bell pickup. Check oil level and add if necessary.
The oil pump inlet screen can be restricting the suction side of the pump which results in cavitation and loss of oil pressure. An air leak in the suction side of the pump will also cause cavitation and loss of pressure. An oil pump bypass valve that is stuck in the open (unseated) position will not allow system pressure to build to maximum pressures. The oil pump gears can be worn sufficiently to cause a reduction in pump output.
Oil Filter and Bypass Valve
If the oil filter is restricted and the filter bypass valve (end of filter housing) is stuck in the closed position, oil pressure may be low. Install a new Caterpillar oil filter element, disassemble the bypass valve, clean the spring and plunger. Be sure the plunger moves freely in the valve before assembling the bypass valve.
Excessive Clearance in Engine Bearings or Open System
Worn components with extreme bearing clearances can cause engine oil pressure to be abnormally low. Any open, broken, or disconnected oil lines or passages will cause loss of oil pressure. Check gallery and crankshaft plugs to be sure they are in place.
Oil Cooler and Bypass Valve
Check the oil cooler oil passages for sludge. A clogged oil cooler with a stuck cooler bypass valve will be accompanied by high engine operating oil temperatures. Oil pressure will usually not lower due to sludge deposits alone. The cooler bypass valve must be stuck closed, or nearly so, to lower the oil pressure.
High Oil Pressure
This condition will occur when an oil pump bypass valve sticks in the closed position and the full pump volume is directed to the engine bearings.
Unusual Bearing Wear
Single components of the engine showing bearing wear at unusually frequent service intervals can be the result of clogged, restricted or broken oil passages. If the oil pressure gauge shows adequate pressure yet a component shows signs of oil starvation, check the branch supply line to that component.
The engine has a pressurized cooling system. Pressurizing the cooling system serves two purposes. First, it permits safe operation at coolant temperature higher than the normal boiling point; thereby, providing a margin of cooling for those intermittent peak loads. Secondly, it prevents cavitation in the water pump and reduces the possibility of air or steam pockets forming in the coolant passages.
Many times, overheating of the engine is caused by failure to make simple systematic inspections. Visual inspections should be made before instrumentation testing.
1. Check coolant level.
2. Inspect for leaks in the system.
3. Inspect the radiator fins. Be certain the air flow through the radiator is not restricted by trash or bent radiator fins.
4. Check for damaged fan blades.
5. Observe if there is any air or combustion gas in the cooling system.
6. Check to see that the cooling system pressure cap sealing surfaces are clean.
7. Check fan belts.
Testing Cooling System
Remember that temperature and pressure go hand-in-hand and neither one can be tested logically without considering the other. For example, the effect of pressurization and altitude on the boiling point of water is shown in the chart.
Cooling System Test Tools
- 9S9102 Thermistor Thermometer Group,9S7373 Air Meter Group,1P5500 Portable Phototach Group,9S8140 Cooling System Pressurizing Pump Group.
To test the cooling system if heating and loss of coolant is a problem use the testing tools.
The 9S9102 Thermistor Thermometer Group is used in the diagnosis of heating problems. The testing procedure is in Special Instruction (GMG-00450).
9S9102 THERMISTOR THERMOMETER GROUP
The 9S7373 Air Meter Group is used to check the air flow through the radiator core. The testing procedure is in Special Instruction (GMG00203).
9S7373 AIR METER GROUP
The 1P5500 Portable Phototach Group is used to check the fan speed. The testing procedure is in Special Instruction (GMG00819).
1P5500 PORTABLE PHOTOTACH GROUP
The 9S8140 Cooling System Pressurizing Pump Group is used to test pressure caps and pressure relief valves, and to pressure check the cooling system for leaks.
9S8140 COOLING SYSTEM PRESSURIZING PUMP GROUP
If overheating and loss of coolant is a problem, a pressure loss in the system could be the cause. If an overheating condition is indicated on the temperature gauge and loss of coolant is not evident, check the accuracy of the temperature gauge. Make this check by installing a 2F7112 Thermometer (using a 6B5072 Bushing) into the water temperature regulator housing.
THERMOMETER INSTALLED (D333C Illustrated)
Be careful when working around an engine if it is running.
Start the engine. Partially cover the radiator or reduce flow of raw water to reduce cooling. The instrument panel temperature gauge should enter the range at point 1 when the test thermometer indicates temperatures shown in the chart.
When testing 5H2954 Indicators without symbol, the pointer must be at position (1) when the test thermometer temperature is 192 to 200° F (89 to 93° C). When testing 5H2954 or 2N2412 Indicators with symbol, the pointer must be at position (1) when the test thermometer temperature is 202 to 210° F (94 to 99° C).
One of the causes of cooling system pressure loss can be a faulty pressure cap seal. Inspect the pressure cap carefully for possible damage to the seal or sealing surfaces. The build-up of deposits on the cap, seal and filler neck should be removed.
Water Temperature Regulators
The opening temperature of the 4L7615 Regulator (bench test in atmospheric pressure) is 164 to 166° F (73 to 74° C). The regulator should be fully open at approximately 180° F (82° C).
The opening temperature of the 6L5851 Regulator (bench test in atmospheric pressure) is 172 to 175° F (78 to 80° C). The regulator should be fully open at approximately 197° F (92° C).
The opening temperature of the 9S9160 Regulator (bench test in atmospheric pressure) is 162 to 167° F (72 to 75° C). The regulator should be fully open at approximately 187° F (86° C).
The opening temperature of the 6N1848 Regulator (bench test in atmospheric pressure) is 175° F (80° C). The regulator should be fully open at 195° F (90° C).
1. Remove the regulator from the engine.
2. Suspend the regulator and a thermometer in a pan of water.
3. Apply heat to the pan and stir the water to maintain uniformity while observing the opening temperature of the regulator.
4. If the regulator does not operate correctly, install a new regulator.
NOTE: When installing a regulator inspect seal for defects and change if necessary.
Cylinder Liner Projection
- 1P2394 Adapter Plate.Two 3H465 Plates.Crossbar (from 8B7548 Push-Puller).Two 5/8"-11 NC bolts, 5.5 in. (118.7 mm) long.Two 4B4281 Washers.1P5510 Liner Projection Tool Group.
Check liner height projection as follows:
1. Make certain that top of block and cylinder liner flange are clean and free of burns.
2. Place adapter plate (4) on top of cylinder liner. Center crossbar (2) on the adapter plate. Using bolts (1), washers (3) and plates (5), secure the crossbar to the cylinder block as shown. Tighten bolts (1) alternately, in four steps to; 5 lb. ft. (0.7 mkg), 15 lb. ft. (2.0 mkg), 25 lb. ft. (3.5 mkg) and finally to 50 lb. ft. (6.9 mkg). Distance from bottom edge of crossbar, to top of cylinder block, must be the same on both sides of the cylinder liner.
3. Zero the dial indicator (7) using the back of gauge (8) with dial indicator (7) mounted in block (6).
4. Measure the cylinder liner projection in at least four locations around the cylinder liner. Projection must be within .0020 to .0056 in. (0.051 to 0.142 mm) and the four measurements should not vary more than .002 in. (0.05 mm). The average projection between adjacent cylinders must not vary more than .002 in. (0.05 mm).
Connecting Rods And Pistons
Use 7S9470 Piston Ring Expander to remove or install piston rings.
Use 7S9417 Piston Ring Compressor to install pistons into cylinder block.
Tighten connecting rod bolt nuts in the following Step sequence:
Heat ring gear to install. Do not exceed 600° F. (315° C.). Install ring gear so chamfered portion of gear teeth face the starter pinion when flywheel is installed.
Heat crankshaft gear and front or rear wear sleeves to 600° F. (315° C.) maximum before installing on crankshaft. Install seal so springloaded lip faces centerline of cylinder block.
Oil Pump Installation (D330C and 3304)
The oil pump can be removed for inspection and service without removing the timing gear cover. With the cover in place, timing marks are not easy to see. Therefore, time both balancer shafts, with respect to No.1 piston at TC or compression stroke, in the following steps.
1. Rotate the crankshaft to bring No.1 piston to TC on compression stroke.
2. Drive dowel (7) back so it is flush with mounting face of oil pump mounting bracket.
3. Rotate both balancer shafts so the flat portion is away from the oil pan plate. Install bolts (6) so they enter in countersunk holes in balancer shafts and limit shaft movement. The bolts should not be tight against the shaft countersunk hole bottom.
4. Position oil pump on bottom of engine block and install the mounting bolts loosely.
5. Install shims if necessary, between pump mounting pads and cylinder block to adjust backlash to .002 to .006 in. (0.05 to 0.15 mm) between gear (4) and (5) and between gears (2) and (3).
6. Drive dowel (7) back in place, through mounting bracket and into cylinder block. Tighten the mounting bolts.
7. Remove bolts (6) and check to see that the countersunk holes are aligned with holes in oil pan plate when No.1 cylinder is in TC position.
Timing mark alignment information shown in the SPECIFICATIONS is to be used when the timing gear cover is removed.
OIL PUMP INSTALLATION (Typical Example)
1. Right side balancer shaft. 2. Right side balancer shaft gear. 3. Idler gear. 4. Oil pump drive gear. 5. Left side balancer shaft gear. 6. Bolt. 7. Dowel.
Most of the electrical system testing can be performed on the engine. The wiring insulation must be in satisfactory condition, the wire and cable connections both clean and tight and the battery fully charged. An "on-engine" test that indicates a defective component usually requires component removal for further testing.
The wire size, color and recommended length is provided in the topic DIAGRAMS in SYSTEMS OPERATION.
- 9S1990 Battery Charger Tester.
The storage battery circuit represents a continuous, although variable, electrical load to the charging unit. If the circuit, positive or negative is opened or broken while the charging unit is charging, the loss of the battery load will result in the charging voltage rising to unsafe levels.
High voltage will damage the charging unit and regulator and may damage other electrical components or instruments.
NEVER DISCONNECT ANY CHARGING UNIT CIRCUIT OR BATTERY CIRCUIT CABLE FROM BATTERY WHEN THE CHARGING UNIT IS PRODUCING A CHARGE.
A load test should be made on a battery that discharges very rapidly when in use. To do this apply a resistance of (for 6 volt: two times and for 12 volt: three times) the ampere/hour rating of the battery across the battery main terminals. Allow the resistance to discharge the battery for 15 seconds and immediately test the battery voltage. A 6 volt battery in good condition will test 4.5 volts; a 12 volt battery in good condition will test 9 volts.
The instructions included with the 9S1990 Battery Charger Tester covers completely the battery testing subject.
The condition and state of charge of the battery at each regular inspection will indicate if the charging system is operating efficiently. An adjustment is necessary when the battery is always in a low state of charge or an excessive amount of water must be added to the battery (more than one ounce of water per cell per week or per every 50 service hours).
Charging units and voltage regulators should be tested on the engine when possible, using wiring and accessories that are a permanent part of the system. Bench testing will provide the technician with an operational test of the charging unit or voltage regulator. Pre-repair testing will advise the depth of needed repairs. Final testing will prove the units are restored to their original operating efficiency.
Before starting the on-engine test the charging system and battery must be checked as stated in the following steps to eliminate possible difficulty:
1. Battery must be at least 75% (1.240 Sp. Gr.) full charged and properly secured in the carrier. The carrier must not place excessive physical strain on the battery.
2. Cables between the battery, starter and engine ground must be of recommended wire size. Wires and cables must be free of corrosion with cable supporting clamps to reduce strain on battery posts.
3. Leads, junctions, switches and panel instruments that are directly related to the charging circuit must be good enough to provide proper circuit control.
4. Inspect the crankshaft pulley, charging unit pulleys and drive belts to be sure they are free of grease and oil and are capable of driving the charging unit load.
Alternator Regulator (Delco)
1. Hollow head screw. 2. Connector.
When an alternator is either overcharging or undercharging the battery, the alternator charging rate can be adjusted. Remove the hollow head screw from the cover of the alternator regulator and use a screwdriver to turn the inside adjustment. Turn the adjustment toward the "+" to increase or toward the "-" to decrease the alternator charging rate.
Alternator Regulator (Motorola)
To raise the voltage (approximately .4 volt on 12 volt system or .6 volt on 24 volt system), remove locknuts from the two terminals closest to the word "HI." Place metal strap over these studs, replace nuts and tighten securely.
To lower voltage (.4 volt on 12 volt system or .6 volt on 24 volt system) install strap over studs closest to word "LO."
REGULATOR STEP ADJUSTMENT
Test equipment needed: Volt-Ammeter that will provide: (D.C. Volts 0 to 16 volts and 0 to 40 volts) (D.C. Ammeter 0 to 10 amps and 0 to 100 amps), a Field Rheostat: 0 to 50 ohms resistance, 50 watts, a Fixed Resistor 1/4 ohm, a Carbon Pile, a Test lamp, battery operated and an Ohmmeter.
TERMINAL AND PARTS IDENTIFICATION
Battery Circuit Test
Condition: Engine not running; oil pressure switch open.
1. Connect test ammeter between alternator POSITIVE OUTPUT terminal and battery positive terminal.
NOTE: Test ammeter remains in the same position throughout all the tests.
2. Connect voltmeter positive lead to battery positive terminal, negative lead to battery negative terminal. Read voltages. Correct voltage on 12 volt system should be 12.0 to 12.6 volts, on 24 volt system, 24.0 to 25.2 volts.
3. Move voltmeter positive lead to battery side of oil pressure switch. Leave negative lead on battery negative terminal. Read voltage. Then move positive lead to alternator POSITIVE OUTPUT terminal. Read voltage. Voltages should read the same as in Step 1. If voltage is lower, check and repair cables, leads or terminals as required.
4. Ammeter should read zero at all times during these tests. If ammeter reads down scale, it indicates a shorted diode in the alternator.
Control Switch Positive Diode Test
Condition: Engine not running; oil pressure switch open.
1. Connect positive lead of voltmeter to alternator TACHOMETER terminal, negative lead to battery negative terminal. Voltmeter should read zero. If voltmeter reads above zero, one or more of the positive rectifier diodes in alternator is shorted.
2. Connect voltmeter positive lead to alternator side of oil pressure switch, negative lead to battery negative terminal. Voltmeter should read zero. If voltmeter reads above zero, oil pressure switch may be shorted.
3. Test ammeter should show zero throughout these tests.
Rotor (Field) Current Draw Test
Condition: Engine not running; oil pressure switch open.
This test requires temporary addition of test carbon pile to battery to reduce voltage to reference level and a field rheostat.
1. Turn load control knob of carbon pile to OFF position and connect leads to battery.
2. Remove lead from No.1 FIELD terminal of alternator.
3. Place field rheostat knob in maximum resistance position; connect leads to No.1 FIELD terminal and POSITIVE OUTPUT terminal of alternator.
4. Connect test voltmeter negative lead to NEGATIVE OUTPUT terminal of alternator, positive lead to NO.1 FIELD terminal.
5. Read all test instruments. Carbon pile voltmeter should read battery voltage. Ammeter should read zero amps. Test voltmeter and test ammeter may indicate near zero depending on resistance value of field rheostat.
6. Slowly decrease resistance of rheostat to zero. Test voltmeter will indicate battery voltage. Ammeter will indicate current draw of rotor (field winding). If ammeter reads excessive current (more than 5 amps) reverse rheostat to maximum resistance. This indicates a short. Disconnect leads and inspect brushes and rotor circuit for cause of high current draw.
7. Slowly apply carbon pile load to battery until test voltmeter reaches reference point shown in table. Check test ammeter for rotor (field) current draw; it should be within limits shown in table.
8. If field current draw falls within the limits shown, rotor winding is good. If field current exceeds the maximum, alternator should be bench tested. Check for defective or dislocated brushes, shorted brush leads, foreign material between slip rings or shorted rotor (field) winding.
9. Turn off carbon pile load immediately after test to avoid discharging battery.
Regulator Load Circuit Loss Test
Condition: Engine not running; oil pressure switch bypassed with jumper cable.
1. Connect negative lead of test voltmeter to alternator NEGATIVE OUTPUT terminal, positive lead to NO.1 FIELD terminal. Voltmeter should read .9 to 1.5 volts less than battery voltage for all systems. This is the maximum allowable voltage drop through the voltage regulator. A reading lower than .9 volts or higher than 1.5 volts indicates a defective voltage regulator.
2. Remove jumper wire from oil pressure switch after completion of test.
Current Output Test
Condition: Engine not running; oil pressure switch open.
1. Connect voltmeter and ammeter leads from carbon pile to battery terminals.
2. Turn load control knob to OFF.
3. Connect test voltmeter and ammeter. Voltmeter should read battery; ammeter should read zero amps.
4. Start engine (oil pressure switch will activate alternator) and run for 5 minutes to stabilize alternator unit temperature.
5. Slowly increase load with carbon pile and increase engine speed until minimum rated current output is reached.
6. Check voltage on test voltmeter.
7. If volts exceed maximum limit, check or replace voltage regulator. If system operates normally at low speeds but cannot obtain minimum rated current output at high engine speeds, check fan belt for proper tension.
8. Disconnect carbon pile load immediately after alternator is stopped to avoid discharging battery.
Use a D.C. voltmeter to locate starting system components which do not function.
Push the start switch button or turn the HEAT-START switch to the START position to energize the starter solenoid. Starter solenoid operation is audible as the starter motor pinion engages with the ring gear on the engine flywheel. The solenoid operation should also close the electric circuit to the motor. Attach one voltmeter lead to the solenoid terminal that is connected to the motor. Ground the other lead. Energize the starter solenoid and observe the voltmeter. A battery voltage reading indicates the malfunction is in the motor. It must be removed for further testing. No voltmeter reading indicates that the solenoid contacts do not close and the solenoid must be repaired or the starter pinion clearance should be adjusted to .36 in. (9.1 mm).
A starting motor solenoid that will not operate may not be receiving battery current. Attach one lead of the voltmeter to the solenoid battery cable connection. Ground the other lead. No voltmeter reading indicates a faulty circuit from the battery. A voltmeter reading indicates further testing is necessary.
Continue the test by attaching one voltmeter lead to the starting motor solenoid small wire terminal and the other lead to ground. Observe the voltmeter and energize the starter solenoid. A voltmeter reading indicates that the malfunction is in the solenoid. No voltmeter reading indicates the starter switch or wiring is the fault.
Attach one lead of the voltmeter to the starter switch battery wire terminal and ground the other lead. A voltmeter reading indicates a defective switch.
A starting motor that operates too slow can be overloaded by excessive mechanical friction within the engine being started. Slow starting motor operation can also be caused by shorts, loose connections and/or excessive dirt within the motor.
Glow plugs can be checked with an ammeter. Disconnect the wire lead from the glow plug terminal on the HEAT-START switch. Install an ammeter, in series, between the disconnected lead and the terminal on the switch. Observe the ammeter with the HEAT-START switch turned to the HEAT position. Each 12 volt glow plug draws approximately 10 amperes; 24 volt, 6 amperes and 30 volt, 4 amperes. The ampere draw of one glow plug multiplied by the number of engine cylinders will be the total ampere draw of the glow plugs in the engine. A low reading is an indication of one or more defective glow plugs. Disconnect one glow plug lead at a time and observe the ammeter with the switch turned to HEAT. The disconnected glow plug that does not change the ammeter reading is the defective glow plug.
When no ammeter reading is obtained, test the HEAT-START switch. Attach one lead of the voltmeter to the glow plug wire terminal on the HEAT-START switch and the other lead to the ground. Observe the voltmeter and turn the switch to HEAT. No voltage indicates that the HEAT-START switch is defective.
Pinion Clearance Adjustment (Delco-Remy)
Whenever the solenoid is installed, the pinion clearance should be adjusted. The adjustment should be made with the starting motor removed.
CONNECTIONS FOR CHECKING PINION CLEARANCE
1. Connector from MOTOR terminal on solenoid to motor. 2. SW terminal. 3. Ground terminal.
Bench test and adjust the pinion clearance at installation of solenoid as follows:
1. Install the solenoid without connector (1) from the MOTOR terminal on solenoid to the motor.
2. Connect a battery, of the same voltage as the solenoid, to the terminal (2), marked SW.
3. Connect the other side of battery to ground terminal (3).
PINION CLEARANCE ADJUSTMENT
4. Shaft nut. 5. Pinion. 6. Pinion clearance.
4. MOMENTARILY flash a jumper wire from the solenoid terminal marked MOTOR to the ground terminal. The pinion will shift into cranking position and will remain there until the battery is disconnected.
5. Push pinion toward commutator end to eliminate free movement.
6. Pinion clearance (6) should be .36 in. (9.1 mm).
7. Adjust clearance by removing plug and turning shaft nut (4).