3500B Series II Marine Engines Caterpillar

The engine speed/timing sensors provide engine information to the Electronic Control Module (ECM). The sensor generates a pulse signal. A loss of the signals from the secondary engine speed/timing sensor and the primary engine speed/timing sensor causes the ECM to stop sending power to the fuel injectors.

The ECM provides the engine speed/timing sensor with 12.5 ± 1.0 VDC. A unique tooth on the timing reference gear generates a unique duty cycle. The signal provides the ECM with information on the engine position.

If the primary engine speed/timing sensor fails, the ECM will use the secondary engine speed/timing sensor until electrical power is removed from the ECM. To prevent any unnecessary down time, replace the primary engine speed/timing sensor at the earliest possible convenience.

Illustration 1	g01030084
Typical example

Test Step 1. Check for "ACTIVE" Engine Diagnostics.

1. Start the Caterpillar Electronic Technician (ET).

2. Start the engine.

3. Operate the engine until normal operating temperatures are obtained.

Expected Result:

There are no active diagnostic codes or there is an active 261-13 diagnostic code.

Results:

• OK - There are no active diagnostic codes or there is an active 261-13 diagnostic code. Proceed to Test Step 2.

• Not OK - There is more than one active diagnostic code.

  Repair: Repair any active diagnostic codes.

  STOP

Test Step 2. Install the Timing Calibration Probe.

1. Turn the Engine Control Switch (ECS) to the OFF position.

2. Remove the timing calibration plug from the flywheel housing.

3. Examine the flywheel through the timing calibration hole. Ensure that the probe is not inserted into the timing pin hole. If necessary, turn the crankshaft.

4. Install the 6V-3093 Transducer Adapter into the hole for the timing calibration at the flywheel.

5. Insert the 6V-2197 Magnetic Transducer through the 6V-3093 Transducer Adapter. Insert the transducer until contact is made with the surface of the flywheel. Move the transducer 0.9 mm (0.04 inch) away from the flywheel.
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   NOTICE
   Do not install the timing calibration probe over the timing pin hole at the flywheel or damage will result.

6. Tighten the nut on the 6V-3093 Transducer Adapter.

7. Connect the 7X-1695 cable from the engine timing calibration probe to the connector P26.

8. Start the engine. Allow the engine to exit cold mode operation.

Expected Result:

The hardware is installed. The engine starts and runs.

Results:

• OK - Proceed to Test Step 3.

Test Step 3. Calibrate the Fuel Injection Timing.

1. Select "Calibrations" from the "Service" menu on the Cat ET. Select the "Timing Calibration" from the "Calibrations" menu.

   Note: Engine speed will be set to 800 rpm by the ECM during the calibration.

2. Follow the instructions on the Cat ET screen.

   Note: If the Cat ET screen reads "COULD NOT CALIBRATE", the timing has not been set.

Expected Result:

The timing calibration procedure was successful.

Results:

• OK - The timing calibration procedure was completed successfully.

  Repair: Disconnect the timing calibration probe before you exit the "Timing Calibration" screen on the Cat ET. Reset the system and check for any diagnostic codes.

  STOP

• Not OK - The timing could not be calibrated.

  Repair: Verify that the engine speed was stable during the testing (± 50 rpm). If the engine speed was unstable or the engine speed could not be controlled within ± 50 rpm because of mechanical factors or electrical factors, refer to the diagnostic procedure Troubleshooting, "Engine Misfires, Runs Rough or Is Unstable".

  If all of the problems have been corrected but the timing cannot be calibrated, check the cable of the 6V-2197 Magnetic Transducer. Check the 6V-2197 Magnetic Transducer in order to verify that the probe is not bent. Verify that the probe is installed correctly before restarting this procedure.

  STOP