C27 and C32 Engine for MD6250 and MD6310 Drill Caterpillar

Use this procedure to troubleshoot a problem with a timing sensor out of calibration. Also, use this procedure if one of the following diagnostic codes is active or easily repeated.

Table 1

J1939 Code and Description	CDL Code and Description	Comments
637-11 Engine Timing Sensor : Other Failure Mode	261-11 Engine Timing Offset fault	The wiring to the sensors has the wrong polarity. The engine will still run. The fuel injection timing may be out of adjustment.

Verify that the wiring is installed correctly to the engine speed/timing sensors.

The engine speed/timing sensors provide engine information to the Electronic Control Module (ECM). The sensor generates a pulse signal. Losing 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.

1. 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, rotate the engine 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.

2. Calibrate the Fuel Injection Timing

   1. Select "Calibrations" from the "Service" menu on Cat^® Electronic Technician (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. 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 Troubleshooting, "Engine Misfires, Runs Rough or Is Unstable" for additional information.

      If all the problems have been corrected but the timing cannot be calibrated, check the cable of the 189-5746 Speed Sensor. Check the 189-5746 Speed Sensor to verify that the probe is not bent. Verify that the probe is installed correctly before restarting this procedure.