KIT (seal) 8J8652 - Caterpillar

System Operation Description:The Electronic Control Module (ECM) provides the engine speed/timing sensor with 12.5 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 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 position of the No. 1 cylinder. The ECM then triggers each unit 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 triggers the termination of the signals to the fuel injectors by the ECM.Note: If the engine timing gear is installed backward, the diagnostic code 190-08 will be generated. 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.Note: The generator set may need a jumper wire on the engine control to provide power to the generator control when the battery disconnect switch is closed and the engine control is in the OFF/RESET position. Unless a timer is installed in the circuit, this jumper wire also provides power to the key switch input of the engine ECM when the battery disconnect switch is closed and the engine control is in the OFF/RESET position. The timer interrupts power to the key switch input of the engine ECM when the battery disconnect switch is closed and the engine control is in the OFF/RESET position. Cycling power to the key switch input of the ECM will reset the ECM and all active diagnostic codes. The bottom dial on the timer should be set to 0.7. The middle dial on the timer should be set to 3 seconds. The top dial on the timer should be set to E.
Illustration 1 g01167840
Typical example
Test Step 1. Inspect Electrical Connectors and Wiring
Turn the engine control to the OFF/RESET mode. Turn the engine battery disconnect switch to the OFF position.
Thoroughly inspect the ECM connector J1/P1 and the machine connector J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with