825704 Mercury SEAL-OIL

Illustration 1 g01043894
Schematic diagram of the detonation sensors
Set the engine control to the OFF/RESET mode. Remove the electrical power from the engine.Note: For the following steps, refer to Troubleshooting, "Inspecting Electrical Connectors".
Thoroughly inspect each of the following connectors:
Connectors for the EIS control module
Connectors for each detonation sensor
Illustration 2 g01044156
Harness side of the EISC connector (EISC-E) Signal from the right detonation sensor (EISC-H) Signal from the left detonation sensor (EISC-M) 13 VDC for the right detonation sensor (EISC-P) 13 VDC for the left detonation sensor (EISC-Y) Ground for the left detonation sensor (EISC-d) Ground for the right detonation sensor
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the detonation sensors.
Illustration 3 g01044294
Detonation sensor (1) Buffer module (2) Accelerometer (3) Wiring
Check the wiring (3) between each accelerometer (1) and each buffer module (2) for corrosion, for abrasion, and for pinch points.
Some engines have replaced the buffer module with a knock sensor. Check the wiring between the detonation sensor and the EISC connector. Refer to Illustration 1.
Check the harnesses and the wiring for abrasion and for pinch points from each buffer module to the EIS control module.Expected Result:The connectors, pins, and sockets are connected properly. The connectors and the wiring do not have corrosion, abrasion, or pinch points.Results:
OK - The components are in good condition with proper connections. Proceed to Test Step 2.
Not OK - The components are not in good condition and/or at least one connection is improper.Repair: Perform the necessary repairs and/or replace parts, if necessary.STOPTest Step 2. Check the Programmable Parameters
Use the DDT or Cat ET to compare the number of detonation sensors on the engine with the number of sensors that are programmed in the EIS control module. Access Screen 31 on the DDT.Expected Result:The number of programmed detonation sensors matches the actual number of detonation sensors on the engine.Results:
OK - Proceed to Test Step 1.
Not OK - Repair: Program the correct number of sensors into the control. Clear all of the diagnostic codes on powerup.STOPTest Step 3. Check for an Open Circuit
Measure the resistance of the harness for the detonation sensor.
For the left detonation sensor, measure the resistance between the points that are listed in Table 1. During each measurement, wiggle the wires in the harness in order to check for an intermittent problem. Be sure to wiggle the wires near each of the connectors.
Table 1
Resistance Measurements for the Harness for the Left Detonation Sensor    
Terminal on the EIS Connector    Terminal on the Connector for the Left Detonation Sensor    
EISC-P (13 VDC for the left detonation sensor)     A (13 VDC for the detonation sensor)    
EISC-Y (Ground for the left detonation sensor)     B (Ground for the detonation sensor)    
EISC-H (Left detonation sensor signal)     C (Left detonation sensor signal)    
For the right detonation sensor, measure the resistance between the points that are listed in Table 2. During each measurement, wiggle the wires in the harness in order to check for an intermittent problem. Be sure to wiggle the wires near each of the connectors.
Table 2
Resistance Measurements for the Harness for the Right Detonation Sensor    
Terminal on the EISConnector    Terminal on the Connector for the Right Detonation Sensor    
EISC-M (13 VDC for the right detonation sensor)     A (13 VDC for the detonation sensor)    
EISC-d (Ground for the left detonation sensor)     B (Ground for the detonation sensor)    
EISC-E (Left detonation sensor signal)     C (Left detonation sensor signal)    Expected Result:Each check of the resistance is less than 2 Ohms.Results:
OK - Each check of the resistance is less than 2 Ohms. The wiring does not have an open circuit. Reconnect the detonation sensors. Proceed to Test Step 7.
Not OK - At least one check of the resistance is greater than 2 Ohms. There is an open in the wiring for a detonation sensor.Repair: Repair the connection and/or the wire, when possible. Replace parts, if necessary. Verify that the problem is resolved.STOPTest Step 4. Check for a Short Circuit
Remove the electrical power from the engine.
Disconnect the EIS connector.
Disconnect the connectors for the detonation sensors.
At the EIS connector, measure the resistance of the harness for the detonation sensor.
For the left detonation sensor, measure the resistance between the points that are listed in Table 3. During each measurement, wiggle the wires in the harness in order to check for an intermittent problem. Be sure to wiggle the wires near each of the connectors.S