14758 Mercruiser BOLT, PULLEY AND HARMONIC BALANCER

Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Start the engine.
C. Run the engine until normal operating temperature is reached.
Note: If the engine will not start, monitor the engine rpm on Cat ET when the engine is being cranked. If necessary, power Cat ET from another battery when the engine is being cranked.
D. Look for these codes and pattern status parameters on Cat ET:
Codes:
• 636-2
• 636-8
• 637-2
• 637-9
Parameters:
• "Engine Speed"
•"Engine Speed Secondary Sensor"
Note: When checking status parameters, engine must be in a cranking state.
Codes
Result: None of the diagnostic codes that are listed above are active or logged and the engine speed is detected.
Repair: If the diagnostic codes that are listed above are not active or logged as well as the "Engine Speed and Secondary Engine Speed" sensor feedback status is showing a valid speed signal and the engine is not running properly, refer to the appropriate engine symptom in this Troubleshooting Manual.
Result: If a 636-2 or a 637-2 code is active or logged.
Proceed to Test Step 2.
Result: Codes 636-8 or 637-9 code is active and no engine rpm is detected. Cat ET is not reporting engine rpm for at least one engine speed/timing sensor while the engine is cranked.
Proceed to Test Step 3.
2. Check the Installation of the Sensor Assembly
A. Turn the main disconnect switch to the OFF position.
B. Visually inspect the sensors without removing the sensor assembly from the engine. Verify that the sensor is secure and the flange of the sensor is flush against the mounting surface.
C. Remove the suspect engine speed/timing sensor from the engine.
D. Ensure that the O-ring seals are installed and free of damage.
Sensor
Result: The O-ring seals are properly installed. The bracket and the seals are free of damage.
Repair: Perform the following procedure:
1. Lubricate the O-ring seals with oil.
2. Fully seat the sensor into the housing.
Note: If the sensor assembly will not fully seat into the engine, replace the sensor assembly.
3. Tighten the bolts.
4. Connect the connector.
5. Ensure that the harness is properly secured, and that the tie-wraps are placed in the correct location.
Proceed to Test Step 3.
Result: At least one of the sensor assembly components is NOT OK.
Repair: Install a new sensor assembly.
If the problem is not resolved, proceed to Test Step 3.
3. Inspect the Electrical Connectors and the Wiring
A. Turn the main disconnect switch to the OFF position.
B. Thoroughly inspect the connectors. Refer to Troubleshooting, Electrical Connectors-Inspect, for additional information.
C. Perform a 45 N (10 lb) pull test on the connector wires.
D. Check the harness for abrasions and pinch points.
Connectors and Wiring
Result: The connectors and wiring appear to be OK.
Proceed to Test Step 4.
Result: There is a problem with the connectors and/or wiring.
Repair: Repair or replace the connectors or wiring. Ensure that all the seals are properly in place and ensure that the connectors are coupled.
If the problem is not resolved, proceed to Test Step 4.
Table 3
Troubleshooting Test Steps Values Results
4. Check the Supply Voltage to the Sensors
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the connectors for the speed/timing sensors.
C. Restore electrical power to the ECM.
D. Measure the voltage at the sensor connectors between following terminals: Crankshaft Speed Timing Sensor:- Terminal 1 (Sensor Supply) and Terminal 2 (Sensor Return)
Camshaft Speed Timing Sensor:
Terminal 1 ( Sensor Return)
Terminal 2 ( Sensor Supply)
Supply Voltage
Note: The sensor supply is 2.5VDC +\- .2 VDC.
Result:The voltage is OK. The sensor supply is inside the 2.3 VDC to 2.7 VDC range.
Proceed to Test Step 5.
Result: The voltage is NOT OK. The sensor supply is outside of the 2.3 VDC to 2.7 VDC range.
Proceed to Test Step 7.
5. Measure Speed Timing Sensor Resistance
A. Turn the Keyswitch to the OFF position
B. Disconnect and remove the affected Speed Timing Sensor
636 Code: Cam Position Sensor
637 Code: Crank Position Sensor
C. Measure resistance between pins 1 and 2
Valid resistance measurement 850-870 Ohms.
Signal Voltage
Result: The sensor resistance is within 850-870 Ohms.
Proceed to Test Step 6.
Result: The sensor resistance is NOT within 850-870 Ohms.
Repair: Replace the engine speed/timing sensor.
If the problem is not resolved, proceed to Test Step 6.
6. Check Return Wire for an Open
A. Turn the main disconnect switch to the OFF position.
B. Remove the connector to the affected camshaft or crankshaft sensor.
C. Measure the resistance between the following locations:
Camshaft position sensor terminal 2 and ECM location J2-67.
Crankshaft position sensor terminal 2 and ECM location J2-65
Signal Voltage
Result: There was less than 10 ohms of resistance between terminal 2 and the appropriate ECM connector pin.
Proceed to Test Step 7.
Result: More than 10 ohms of resistance was measured between the sensor connector and ECM connector.
Repair: There is an open circuit in the wiring harness. Repair or replace the wiring harness.
7. Check Return Wire for a Short Circuit to Ground
A. Turn the main disconnect switch to the OFF position.
B. Remove the connector to the affected camshaft or crankshaft sensor.
C. Measure the resistance between the following locations:
Camshaft position sensor terminal 2 and Engine Ground
Crankshaft position sensor terminal 2 and Engine Ground
Supply Voltage
Result: There was more than 100 K ohms of resistance between the sensor terminal 2 and engine ground.
Repair: The signal wire is OK. There is no short circuit detected.
Proceed to Test Step 8.
Result: There was less than 100 K ohms of resistance between sensor terminal 2 and engine ground.
Repair: There is a short to ground in the wiring harness. Repair or replace the wiring harness.
8. Check the Return Wire for a Pin to Pin Short Circuit
A. Turn the keyswitch to the OFF position.
B. Remove the connector to the affected camshaft or crankshaft sensor.
C. Disconnect the J2 connector at the ECM.
D. Measure the resistance between the following locations for the sensor:
Crankshaft Return J2-65 and all ECM co