The Electronic Control Module (ECM) has the ability to compensate for the mechanical differences between the Top Center (TC) of the flywheel and the TC of the timing gear on the left rear camshaft gear. A magnetic transducer signals the TC of the flywheel to the ECM when the TC hole on the flywheel passes beneath the transducer. The engine speed/timing sensor signals the TC of the timing gear to the ECM. Any offset between the TC of the flywheel and the TC of the timing gear is stored into memory.
Calibration of the timing is required only after the following circumstances:
- Replacement of the ECM
- Adjustment of the timing gear and/or the rear gear train
- Replacement of the timing gear and/or the rear gear train
Note: The 261-13 Engine Timing Calibration calibration required is generated only for an ECM that has never performed a timing calibration.
The calibration procedure is initiated with the Caterpillar Electronic Technician (ET).
Test Step 1. Prepare the Engine for the Calibration
- Set the engine control to the OFF/RESET position.
Note: There are two holes on either side of the engine for the transducer adapter. The holes are located on the front face of the flywheel housing. Either hole may be used. The hole on the left side of the engine is shown in Illustration 1.
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Illustration 1 g01391809 Location of the flywheel housing timing hole (left side engine view)
(1) Connector for the magnetic transducer
(2) Hole for the transducer adapter - Remove the plug from either hole. Install the 6V-3093 Transducer Adapter into the hole.
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NOTICE The timing hole in the flywheel must not be aligned with the hole for the transducer. The transducer will be damaged on engine start-up if the transducer is installed through both holes. Rotate the flywheel for more than 10 degrees before or after the TC position in order to move the flywheel hole away from the hole for the transducer. Always confirm that the holes are not aligned.
- Confirm that the hole in the flywheel housing for the transducer is not aligned with the timing hole in the flywheel.
- Remove the protective end cap from the 6V-2197 Magnetic Transducer. Insert the transducer into the adapter until the transducer contacts the surface of the flywheel. Move the transducer
1 mm (0.04 inch) away from the surface of the flywheel. Tighten the nut on the adapter in order to secure the transducer in place. - Connect the appropriate end of 7X-1695 Cable to the transducer. Connect the other end of the cable to the two terminal connector for the engine timing calibration probe.
- Establish communication between Cat ET and the ECM. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
Results:
- Continue to the next test step.
Test Step 2. Calibration
Note: Calibration is a two-step process. The new timing reference is calculated first. The reference is based on the signals from the transducer and the speed/timing sensor. Next, the new timing reference is programmed into the permanent memory of the ECM.
- Start the engine. Operate the engine at the rated speed and load.
- Select "Service" from the main menu on Cat ET. Select "Calibrations" from the menu. Select "Timing Calibration".
- Use either of the following methods in order to initiate the calculation of the new timing reference:
- Press the space bar on the keyboard of the PC.
- Click the left mouse button on the "Continue" button in the lower left corner of the Cat ET screen.
Cat ET will indicate "Please wait...Calculating the new Timing Reference". After a few moments, Cat ET will display "The ECM has calculated the Timing Reference" and "Choose the Continue button to program the Timing Reference".
- Use either of the following methods in order to program the new timing reference:
- Press the space bar on the keyboard of the PC.
- Click the left mouse button on the "Continue" button in the lower left corner of the Cat ET screen.
Expected Result:
After a few moments, Cat ET will display "CALIBRATION SUCCESSFUL".
Results:
- OK - The timing calibration was successful.
STOP
- Not OK - Cat ET displayed "COULD NOT CALIBRATE". The calibration was unsuccessful.
Repair: If the calibration failed in the first step, verify that the engine rpm was stable during the calibration (± 50 rpm). Verify that there are no active diagnostic codes which can prevent the calibration. Repeat the calibration procedure.
If the calibration is still unsuccessful, check the installation of the tools and check the operation of the tools. Check the 7X-1695 Cable for continuity. Verify that the transducer is not bent, open, or shorted internally. Repeat the calibration procedure.
Excessive backlash in the gear train will cause inconsistent timing. Refer to Disassembly and Assembly for identifying and repairing a gear train problem.
STOP
- Not OK - The calibration was completed successfully. However, the "261-13 Engine Timing calibration required" diagnostic code is still active.
Repair: Replace the ECM according to the instructions in Troubleshooting, "Replacing the ECM".
STOP