3208 TRUCK ENGINE Caterpillar


Testing And Adjusting

Usage:



Low Emission System Inspection And Troubleshooting

1. Visual Inspection ... A visual inspection to check the operation of the Low Emission System can be done at the time of each oil change.

With the engine stopped, lever (1) on valve (2) must be a small amount above horizontal.


LEVER POSITION: ENGINE STOPPED
1. Lever. 2. Valve.

When the engine is started and at idle, lever (1) on valve (2) must be down below horizontal.


LEVER POSITION: ENGINE AT IDLE
1. Lever. 2. Valve.

If the lever moves to the positions shown, the Low Emissions System is operational. Inspect the system again at the next oil change.

If no movement of the lever is seen, see Step 2.

2. Check for 12 V at Shutoff Solenoid ... Use the 6V7070 Multimeter to measure the voltage at the shutoff solenoid. The voltage must be between 11.8 and 16 volts.

3. Low or No Voltage to Shutoff Solenoid ...

A. Check battery voltage. If battery voltage is less than 8 volts, put a charge to the battery. If the battery will not hold a charge, install a new battery. Check the operation of the alternator.

B. Check wiring to shutoff solenoid. Clean all wire connections and tighten securely. Be sure the wire to the solenoid is NOT a "resistance" wire.

NOTE: A minimum of 12 volts must be at the fuel shutoff solenoid with the engine running for correct operation of the Low Emission System.

When the voltage problem is corrected and 12 volts is available at the fuel shutoff solenoid, make another visual inspection of the Low Emission System.

4. 12 Volts Available at Shutoff Solenoid ...

Test the electronic control, on-engine, with the 6V3060 Tester. See Test Procedure in this section.

5. Electronic Control and Switch Show a Defect ...

Bench test the electronic control and switch with the 6V3060 Tester to determine which is defective. See Test Procedure in this section.

6. Electronic Control and Switch OK ...

Test the solenoids, on-engine, with the 6V3060 Tester. See Test Procedure in this section.

7. Solenoids Check OK ...

Check for free movement of actuator and valve. Check adjustment of actuator linkage. See Adjustment Procedure in this section.

1. Air Cleaner and/or Precleaner Element Has A Restriction ... If the air cleaner has a restriction indicator, see if the red piston is in view. If there is no restriction indicator, restriction can be checked with a water manometer or a vacuum gauge (which measures in inches of water). Make a connection to the engine side of the air cleaner or to the engine inlet manifold. Check with the engine running at full load rpm. Maximum restriction is 25 in. (635 mm) of water. If a gauge is not available, visually check the air cleaner and/or precleaner element for dirt. If the element is dirty, clean the element or install a new element.

2. Exhaust System Has a Restriction ... Make a visual inspection of the exhaust system. Check for damage to piping or for a bad muffler. If no damage is found, you can check the system by checking the back pressure from the exhaust (pressure difference measurement between exhaust outlet and atmosphere). The back pressure must not be more than 34 in. (864 mm) of water. You can also check by removing the exhaust pipes from the exhaust manifolds. With the exhaust pipes removed, start and load the engine on a chassis dynamometer to see if the problem is corrected.

3. Actuator of Valve Stuck Closed or Partly Closed ... Disconnect the actuator rod from the lever on the valve shaft. Determine if actuator or valve is stuck. If the valve is stuck, check the adjustment of the actuator linkage. If the actuator linkage adjustment is ok, remove the valve and replace worn or damaged parts. If the actuator rod is stuck, disassemble the actuator and clean. Replace any worn parts. Be sure the oil is changed at regular intervals.

4. Fuel Setting Incorrect for Application ... Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual. See the FUEL SETTING AND RELATED INFORMATION FICHE for the correct fuel setting.

5. Switch Contacts Not Adjusted Correctly ... Check the settings of the X and Y contacts as per Fuel Setting in this section.

Low Emission Systems

FUEL SETTING

5P6577 Fuel Setting Tool Group or5P4203 Sleeve Metering Field Service Tool Group
5P6602 Adapter3P1565 Collet3P1567 Dial Indicator5P6531 Contact Point, 2.25 in. (57.2 mm) long8S7271 Setscrew5P4205 Wrench1D4533 Bolt1D4538 Bolt3J6956 Spring5P298 Pin (with 17.8507 stamped on it)

The fuel setting procedure that follows can be done with the fuel pump unit on or off the engine.


NOTICE

The outside surfaces of the fuel pump unit must be clean and free of dirt before any service work is done. Dirt that enters the fuel pump unit will cause much damage.


1. Remove switch cover (2) and solenoid (1).


3208 ENGINE FUEL PUMP UNIT
1. Solenoid. 2. Switch cover.


INSTALLATION OF ADAPTER
3. 5P6602 Adapter. 4. 3P1565 Collet. 5. 3J6956 Spring. 6. 5P298 Zero Set Pin (with 17.8507 stamped on it).

2. Install 5P298 zero set pin (6) in hole. Put 3J6956 Spring (5) on pin (6). Install 3P1565 Collet (4) on 5P6602 Adapter (3). Install Adapter (3).

3. Install setscrew (7) in adapter (3).


SETSCREW INSTALLED
7. 8S7271 Setscrew.

4. Use wrench (8) and tighten setscrew (7) until pin (6) is against pump housing. Install dial indicator (9) with 5P6531 Contact Point in collet (4). Move governor control lever (11) to the full load position. Make an adjustment to the dial indicator (move indicator up or down) until both hands are at zero. Tighten nut of collet only enough to hold indicator in position. Loosen lock (10) and turn bezel until large hand is on zero. Tighten lock (10). Use wrench (8) and turn setscrew (7) counterclockwise six turns.


ADJUSTMENT OF DIAL INDICATOR
8. 5P4205 Wrench. 9. 3P1567 Dial Indicator. 10. Lock. 11. Governor control lever.

5. Release governor control lever (11), and move it to low idle position. Connect the wire clip end of a circuit tester to contact (Z) of switch (12). Put the other end of tester to a good ground on fuel pump. Slowly move governor control lever (11) toward high idle position until light in circuit tester just comes on. Do this several times to make sure of the dimension on indicator (9). This dimension is the fuel setting. For the correct fuel setting, see the FUEL SETTING AND RELATED INFORMATION FICHE.


CHECK OF FUEL SETTING
12. Switch. 13. Fuel setting adjustment setscrew. Z. Fuel setting contact.

6. If the dimension on indicator (9) is not correct, make an adjustment to fuel setting. Loosen locknut and turn screw (13) until dimension on indicator (9) is correct.

7. When the adjustment is correct, tighten locknut. Check the adjustment by doing steps 1 through 5 again.

NOTE: If an adjustment is made to the fuel setting, check the adjustment for the contacts of the switch. The same tools are used to adjust the contacts of the switch that are used for fuel setting.

Adjustment Of Switch Contacts

NOTE: Make reference to FUEL SETTING for the tools needed for this procedure.

The fuel setting must be correct before an adjustment is made to the switch contacts.

1. Remove switch cover (2) and solenoid ( 1).

2. Install 5P298 Zero Set Pin (6) in hole. Put 3J6956 Spring (5) on pin (6). Install 3P1565 Collet (4) on 5P6602 Adapter (3). Install adapter (3).

3. Install setscrew (7) in adapter (3).


3208 ENGINE FUEL PUMP UNIT
1. Solenoid. 2. Switch cover.


INSTALLATION OF ADAPTER
3. 5P6602 Adapter. 4. 3P1565 Collet. 5. 3J6956 Spring. 6. 5P298 Zero Set Pin (with 17.8507 stamped on it).


SETSCREW INSTALLED
7. 8S7271 Setscrew.

4. Use wrench (8) and tighten setscrew (7) until pin (6) is against pump housing. Install dial indicator (9) with 5P6531 Contact Point in collet (4). Move governor control lever (11) to the full load position. Make an adjustment to the dial indicator (move indicator up or down) until both hands are at zero. Tighten nut of collet only enough to hold indicator in position. Loosen lock (10) and turn bezel until large hand is on zero. Tighten lock (10). Use wrench (8) and turn setscrew (7) counterclockwise six turns.

5. Connect the wire clip end of a circuit tester to contact (X) of switch (12). Put the other end of tester to a good ground on fuel pump. Move governor control lever (11) slowly toward high idle position until light in circuit tester just comes on. Do this several times to make sure of the dimension on indicator (9). Compare this measurement to the CONTINUITY CHECK CHART. See the FUEL SETTING AND RELATED INFORMATION FICHE for the correct fuel setting.


ADJUSTMENT OF DIAL INDICATOR
8. 5P4205 Wrench. 9. 3P1567 Dial Indicator. 10. Lock. 11. Governor control lever.

6. Connect the wire clip end of a circuit tester to contact (Y) of switch (12). Put the other end of tester to a good ground on fuel pump. Move governor control lever (11) slowly toward high idle position until light in circuit tester just comes on. Do this several times to make sure of the dimension on indicator (9). Compare this measurement to the CONTINUITY CHECK CHART. See the FUEL SETTING AND RELATED INFORMATION FICHE for the correct fuel setting.


CHECK OF CONTACT X
12. Switch. X. Contact.


CHECK OF CONTACT Y
12. Switch. Y. Contact.

7. If the X or Y contact adjustment is not correct as shown in the CONTINUITY CHECK CHART, use a socket and make an adjustment. Turn the contacts clockwise to make the indicator reading smaller. After an adjustment is made, do Steps 5 and 6 again to check the setting.

NOTE: If too much adjustment is needed, check to see if the load stop pin is bent. If the load stop pin is bent, replace with a new part. When a new load stop pin is installed, adjust the fuel setting and switch contacts X and Y.


SWITCH POSITIONS
X. Contact. Y. Contact. Z. Fuel setting contact.

Testing The Electronic Control And Switch "On Engine" With 6V3060 Tester

1. Stop the engine and turn OFF all electrical power to the engine.


6V3060 TESTER CONNECTED TO ENGINE
1. Solenoid energizer switches. 2. Engine test/bench test switch. 3. On-off switch. 4. Tester cable (marked SOLENOIDS). 5. Tester cable (marked EGR COVER). 6. Tester wire (marked RACK SWITCH). 7. Black wire clip. 8. Red wire clip.

2. Connect black wire clip (7) to a good electrical ground and connect red wire clip (8) to the terminal on the fuel shutoff solenoid.

3. Disconnect connector (9) for the wires that go from the electronic control to the solenoids. Connect tester cable (5) marked EGR COVER to the connecter on the wires that go to the electronic control. Connect tester cable (4) marked SOLENOIDS to the connecter on the wires that go to the solenoids.

4. Connect the tester wire (6) marked RACK SWITCH to the rack contact on the switch cover.


LOW EMISSION ENGINE
9. Connecter.

5. Put ON/ OFF switch (3) in the OFF position and put the solenoid energizer switches (1) in the OFF position. Put the engine test/bench test switch (2) in the engine test position.

6. Turn on the electrical power to the engine. DO NOT start the engine.

7. Put the ON/ OFF switch (3) in the ON position. The light next to the switch must come on.

NOTE: If the ON/OFF switch will not stay in the ON position, there can be a short circuit in the electronic control or switch cover. Do a bench test on the electronic control and switch cover.

If the ON/OFF switch stays on, and the light is on, check to see if one of the EGR VALVE POSITION lights is flashing. If at least one light is flashing, do the remainder of the tests. If no light is flashing, do a bench test on the electronic control and switch cover.

------ WARNING! ------

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

--------WARNING!------

8. Start the engine and test the electronic control and switch cover with one of the methods that follow.

A. NO LOAD TEST.

a. Put the transmission in neutral and apply the parking brake.

b. Rapidly increase the speed of the engine to high idle while checking the EGR VALVE POSITION lights. The flashing light must move from FULL EGR to PARTIAL EGR, and then to NO EGR as the engine speed increases. As the engine speed becomes constant at high idle, the flashing light must move from NO EGR to PARTIAL EGR, and then to FULL EGR. At the set point (balance point) the RACK CONTACT light will flash.

NOTE: It is not necessary for the RACK CONTACT light to flash in order to have correct Low Emission System operation.

B. LOAD TEST.

a. This test can be done either on a dynamometer or by driving the vehicle to get the low, medium, and full load conditions. The tester must be moved to a location near the operator so the tester lights can be seen. As the different loads are put on the engine, the light that best describes the load condtion of the engine must flash. The RACK CONTACT light will come on when the engine gets to the set point (balance point).

If the correct lights DO NOT flash according to the load conditions of the engine, remove the electronic control and switch cover. Do a bench test on the electronic control and switch cover.

Testing The Solenoids And Actuator "On Engine"

Leave the tester connected as for TESTING THE ELECTRONIC CONTROL AND SWITCH "ON ENGINE."

For this test, the valve lever must be observed when the tester switches are moved.

------ WARNING! ------

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

--------WARNING!------

Start the engine and run at low idle.


LEVER POSITION AT FULL LOAD (Figure 1.)
1. Lever.


LEVER POSITION AT MEDIUM LOAD (Figure 2.)
1. Lever.


LEVER POSITION AT IDLE OR NO LOAD (Figure 3.)
1. Lever.

Move the SOLENOID ENERGIZER switches to the positions shown in the chart. Check to see that the position of lever (1) is as shown in the illustrations.

If the valve lever does not move to all three positions, check the actuator assembly. If no problem can be found with the actuator, bench test the solenoids to check for correct operation.

Bench Test For Low Emission System Components With The 6V3060 Tester

The tester must be connected to a source of 12 VDC for a bench test. Connect the black (-) wire to the negative (-) terminal of the power source. Connect the red wire (+) to the positive (+) terminal of the power source.

Bench Testing the Electronic Control and Switch Cover

1. Put the ON/OFF switch in the OFF position. Put the BENCH TEST/ENGINE TEST switch in the BENCH TEST position.


6V3060 TESTER
1. Rack contact clip. 2. Adapter wire. 3. Solenoid connecter. 4. Ground wire.

2. Remove the switch cover and electronic control from the engine.

3. Install the switch cover in the bench test fixture.

4. Connect the wires from the switch cover to the electronic control. Connect the solenoid wires from the electronic control to solenoid connector (3) on the tester.

5. Connect a jumper wire from ground wire (4) on the electronic control to a good ground on the switch cover. Connect adapter wire (2) to the cover power connection in the tester and to the red wire from the electronic control.

6. Connect rack contact clip (1) to the screw on top of the switch cover.

7. Put the ON/OFF switch in the ON position. If the ON/OFF switch will not stay in the on position, or the light next to the switch is not on, the switch cover or electronic control is defective. Check the switch cover for continuity between the contacts and the ends of the wires, and, for a short circuit between contacts.

If the ON/OFF switch stays in the ON position and the light is ON, continue with the test.

8. Move the LOAD SELECTOR switch on the tester to each of the three positions. The corresponding light for each position must flash when the switch is in that position. If any of the lights flash when the switch is not in the corresponding position, the electronic control is defective.

9. When the LOAD SELECTOR switch is in the FULL LOAD position, the RACK CONTACT light must flash. If the light does not flash, check the clip on top of the switch cover to make sure it is making contact. If the light still will not come on, the switch cover has a defect.

NOTE: A defect in the RACK CIRCUIT will NOT affect the operation of the Low Emission System.

Bench Testing The Solenoids

1. Put the ON/OFF switch in the OFF position. Put the SOLENOID ENERGIZER switches in the SOL. No. 1 and SOL. No. 2 (OFF) positions.


BENCH TEST OF SOLENOID
1. Jumper wire.

2. Connect the wire of the solenoid to be tested to the female side of the connector on the test cable marked SOLENOIDS. Connect one end of jumper wire (1) to bare metal on the end of the solenoid, and connect the other end of the jumper wire to the negative (-) terminal of the power supply.

3. Put the ON/OFF switch in the ON position. Move SOL. No. 1 switch to the ON position. A sound (click) must be heard as the plunger inside the solenoid moves to the open position. If no sound (click) is heard, the solenoid is defective and must be replaced.

Adjustment Of Actuator Linkage

2H2522 Pin; Serial Nos. 32Y1-UP, 51Z1-51Z212101A646 Pin; Serial Nos. 51Z21211-UP

1. Remove exhaust recirculation tube from the exhaust and air inlet manifolds.

2. Move lever (1) down as far as it will go. Check the small valve opening with pin (5) as shown. With pin (5) in full contact with the side of valve opening, the valve plate must just contact the pin. If the valve plate does not contact the pin or if the pin will not make full contact with the side of the valve opening, the actuator linkage must be adjusted.


ACTUATOR LINKAGE
1. Lever. 2. Rod end. 3. Locknut. 4. Rod.


CHECKING VALVE PLATE OPENING
5. Pin.

3. Loosen locknut (3) and turn rod (4) to adjust the actuator.

4. Do Step 2 again to check the adjustment.

5. Tighten locknut (3) to 63 ± 13 lb. in. (7.0 ± 1.5 N·m).

6. Install exhaust recirculation tube.

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