3516B Engine for Caterpillar Built Machines Caterpillar

The Electronic Control Module (ECM) provides the Engine Speed/Timing Sensor with 12 ± 1.0 VDC. The Engine Speed/Timing Sensor provides a pulse signal to the ECM. The signal is created as the timing reference gear rotates past the pickup of the Engine Speed/Timing Sensor. The timing reference gear is mounted on the rear of the left camshaft. A unique tooth pattern on the timing reference gear allows the ECM to determine the crankshaft position, rotation, and rpm.

The Engine Speed/Timing Sensor generates a pulse signal to the Electronic Control Module (ECM) as each tooth passes the sensor. The ECM counts the pulses in order to determine the engine rpm. The ECM memorizes the pattern of the pulses. The ECM compares that pattern to a standard pattern in order to determine the crankshaft position. The ECM uses this information to determine the No. 1 cylinder. The ECM then triggers each fuel injector to fire in the correct firing order and at the correct time. The actual timing and duration of each injection is determined by the ECM. The ECM uses engine rpm and engine load to determine the timing and duration of injection. The loss of the signal from the Engine Speed/Timing Sensor generates a diagnostic code. The loss of the signal from the Engine Speed/Timing Sensor triggers the termination of the signals to the fuel injectors by the ECM.

Note: If the engine timing gear is installed backward, the ECM will generate a diagnostic code. The diagnostic code that is generated will be 190-08 Engine Speed signal abnormal. If this code is active, the ECM will not fire the injectors. You may refer to the diagnostic procedure Troubleshooting, "Engine Monitoring System" in order to determine if there are any parameters that are affecting engine operation.

Illustration 1	g00920458

Test Step 1. Check for Connector Damage.

1. Turn the keyswitch to the OFF position.

2. Turn the battery disconnect switch to the OFF position.

3. Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.

4. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.

5. Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).

6. Check the customer connector (allen head screw) for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in).

7. Check the harness and the wiring for abrasion and for pinch points.

Expected Result:

All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring should be free of corrosion, of abrasion or of pinch points.

Results:

• OK - The connectors and wiring are okay. Proceed to test step 2.

• Not OK - The connectors and/or wiring are not okay.

  Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

Test Step 2. Check for an "ACTIVE" Diagnostic Code.

1. Connect the Caterpillar Electronic Technician (ET) to the service tool connector J42.

2. Turn the battery disconnect switch to the ON position.

3. Turn the keyswitch to the STOP position. The engine should be off.

4. Check the diagnostic codes on the Cat ET. Check for active engine diagnostic codes.

Expected Result:

The Cat ET indicates that a diagnostic code of CID-FMI 190-03 Engine Speed open/short to +batt is active.

Results:

• OK - The CID-FMI 190-03 is active. Proceed to test step 3.

• Not OK - The CID-FMI 190-03 is not active. Proceed to test step 4.

Test Step 3. Check for Shorts in the Wiring Harness.

1. Turn the keyswitch to the OFF position.

2. Turn the battery disconnect switch to the OFF position.

3. Disconnect connectors J1/P1 and J20/P20.

4. Measure the resistance between J20-A (996-GN) and J20-B (998-BR).

5. Measure the resistance between J20-A (996-GN) and J20-C (999-WH).

6. Measure the resistance between J20-B (998-BR) and J20-C (999-WH).

7. Measure the resistance from the following points to engine ground: J20-A, J20-B and J20-C.

Expected Result:

The resistance should be more than 20,000 Ohms.

Results:

• OK - The resistance is greater than 20,000 Ohms. Proceed to test step 5.

• Not OK - The resistance is less than 20,000 Ohms. There is a short circuit in the harness or the connectors.

  Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

Test Step 4. Check the Engine Speed/Timing Sensor.

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NOTICE
Be sure to extend the sliphead before you install the Engine Speed/Timing Sensor. Also check that the engine timing gear is in a position that will not allow the sliphead of the Engine Speed/Timing Sensor to protrude into one of the slots of the engine timing gear. This is done visually with a flashlight prior to the installation of the Engine Speed/Timing Sensor. Turn the crankshaft to rotate the engine timing gear, if necessary, to position the gear in a place that will not allow the sliphead to protrude into a slot. If the sensor sliphead does protrude into one of the slots, the sliphead will be broken off as the gear begins to rotate.

1. Turn the keyswitch to the OFF position.

2. Turn the battery disconnect switch to the OFF position.

3. Disconnect J20/P20 and remove the Engine Speed/Timing Sensor.

4. Inspect the plastic sliphead for damage.

5. Check the tension. Gently extend the sliphead 3.5 mm (0.14 inch). Return the sliphead to the original position.

6. Extend the sliphead.

7. Install the Engine Speed/Timing Sensor.

Expected Result:

The sliphead should take at least 22 N (5 lb) of force in order to push in the sliphead from the extended position.

Results:

• OK - The Engine Speed/Timing Sensor and the sliphead are undamaged. The tension on the sliphead is normal. Reinstall the sensor. Proceed to test step 6.

• Not OK - The Engine Speed/Timing Sensor or the sliphead is damaged and/or the sliphead has insufficient tension.

  Repair: Replace the Engine Speed/Timing Sensor. Calibrate the sensor. Perform the calibration procedure Troubleshooting, "Engine Speed/Timing Sensor - Calibrate".

  Stop.

Test Step 5. Check the Resistance through the Harness.

1. Use a suitable piece of wire to short J20-A (996-GN) to J20-B (998-BR).

2. Measure the resistance from P1-32 (996-GN) and P1-29 (998-BR).

3. Use a suitable piece of wire to short J20-A (996-GN) to J20-C (999-WH).

4. Measure the resistance between P1-32 (996-GN) and P1-38 (999-WH).

5. Remove all shorts and reconnect J1/P1 and J20/P20.

Expected Result:

The resistance should be less than 10 Ohms through the wires.

Results:

• OK - The resistance is less than 10 Ohms. Proceed to test step 6.

• Not OK - The resistance is greater than 10 Ohms. There is an open circuit or excessive resistance in the harness or connectors.

  Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

Test Step 6. Check the Engine RPM on the Cat ET.

1. Connect the Cat ET to the service tool connector J42.

2. Turn the battery disconnect switch to the ON position.

3. Turn the keyswitch to the ON position. Crank the engine. Start the engine, when possible.

4. Observe the display on the Cat ET screen.

5. Turn the keyswitch to the OFF position.

Expected Result:

The Cat ET screen should display a steady engine speed between 100 and 250 rpm while the engine is cranking.

Results:

• OK - The engine speed is between 100 and 250 rpm. The Engine Speed/Timing Sensor is operating normally at this time.

  Repair: There may be an intermittent problem. If the problem is intermittent, perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

  Stop.

• Not OK - The engine speed is not between 100 and 250 rpm while the engine is cranking. The Engine Speed/Timing Sensor is not operating normally at this time. Proceed to test step 7.

Test Step 7. Check the Supply Voltage to the Sensor.

1. Turn the keyswitch to the ON position. The engine should be off.

2. Measure the voltage between P20-A and P20-B at the sensor connector.

Expected Result:

The supply voltage should be 12 ± 1.0 VDC.

Results:

• OK - The supply voltage is 12 ± 1.0 VDC. Proceed to test step 8.

• Not OK - The supply voltage is not 12 ± 1.0 VDC. Proceed to test step 10.

Test Step 8. Check the Signal Voltage at the Sensor.

1. Remove the wire P20-C from the sensor connector.

2. Measure the voltage between the sensor signal wire and P20-B. Crank the engine and measure the voltage between the sensor signal wire and P20-B.

3. Turn the keyswitch to the OFF position.

4. Turn the battery disconnect switch to the OFF position.

5. Reconnect the signal wire and connector P20.

Expected Result:

The voltage should measure less than 3 VDC or more than 9 VDC when the keyswitch is in the ON position and the engine is not cranking. While the engine is cranking, the voltage should be between 2.0 VDC and 7.0 VDC.

Note: The voltage output is determined by the presence or the absence of a tooth on the timing gear.

Results:

• OK - The Engine Speed/Timing Sensor is producing the correct output signal. Proceed to test step 9.

• Not OK - The Engine Speed/Timing Sensor is not producing the correct output signal.

  Repair: Replace the Engine Speed/Timing Sensor. Calibrate the sensor. Perform the calibration procedure Troubleshooting, "Engine Speed/Timing Sensor - Calibrate".

  Stop.

Test Step 9. Check the Signal Voltage at the ECM.

1. Turn the keyswitch to the OFF position.

2. Turn the battery disconnect switch to the OFF position.

3. Remove the sensor signal wire on pin P1-38 from ECM connector P1.

4. Turn the battery disconnect switch to the ON position.

5. Turn the keyswitch to the STOP position. The engine should be off.

6. Measure the signal voltage between the signal wire 999-WH and P1-29 (998-BR) at the ECM connector P1.

7. Crank the engine and measure the voltage between the signal wire 999-WH and P1-29 (998-BR) at the ECM connector P1.

8. Turn the keyswitch to the OFF position.

9. Turn the battery disconnect switch to the OFF position.

10. Replace all wires. Reconnect ECM connector J1/P1.

Expected Result:

The voltage should measure less than 3 VDC or more than 9 VDC when the keyswitch is in the ON position and the engine is not cranking. While the engine is cranking, the voltage should be between 2.0 VDC and 7.0 VDC.

Note: The voltage signal is generated by the presence or the absence of a tooth on the timing gear.

Results:

• OK - A correct voltage appears at ECM connector P1 but the ECM is not reading the signal.

  Repair: Replace the ECM. Refer to the diagnostic procedure Troubleshooting, "Replacing the ECM".

  Stop.

• Not OK - There is an intermittent problem in the Engine Speed/Timing circuit.

  Repair: The problem is between the ECM and the Engine Speed/timing Sensor. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

Test Step 10. Check the Supply Voltage at the ECM.

1. Turn the keyswitch to the OFF position.

2. Turn the battery disconnect switch to the OFF position.

3. Remove wire P1-32 from ECM connector P1. Install a wire jumper into the socket for P1-32.

4. Turn the battery disconnect switch to the ON position.

5. Turn the keyswitch to the STOP position. The engine should be off.

6. Measure the supply voltage between the wire jumper and P1-29.

7. Turn the keyswitch to the OFF position.

8. Turn the battery disconnect switch to the OFF position.

9. Remove the wire jumper and replace all wires. Reconnect ECM connector J1/P1.

Expected Result:

The supply voltage should be 12 ± 1.0 VDC.

Results:

• OK - The supply voltage is 12 ± 1.0 VDC. There is an open circuit or excessive resistance in the engine harness between the ECM and the engine speed/timing sensor.

  Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

• Not OK - The supply voltage is not 12 ± 1.0 VDC. The supply voltage is incorrect.

  Repair: Perform the diagnostic functional test Troubleshooting, "Electrical Power Supply".

  Stop.