850814T 4 Mercury PLATE, Exhaust

Use this procedure when the engine will not start and the electronic service tool indicates a faulty sensor. The electronic service tool will display "Not Detected" against the faulty sensor on the "No Start Parameter" screen.
Illustration 1 g06104871
Schematic for the speed/timing sensors
Illustration 2 g06104821
C4.4 speed/timing sensor locations
(1) Primary speed/timing sensor
(2) Secondary speed/timing sensor
Illustration 3 g06104846
C6.6 speed/timing sensor locations
(1) Primary speed/timing sensor
(2) Secondary speed/timing sensor
Illustration 4 g06104859
Speed/timing sensor
(3) 8 VDC Supply
(4) SignalThe engine uses two engine speed/timing sensors. The primary speed/timing sensor is on the left-hand side of the cylinder block close to the flywheel housing. The primary speed/timing sensor generates a signal by detecting the movement of the teeth that are on the crankshaft timing ring. The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM uses the signal from the speed/timing sensor to calculate the position of the crankshaft. The signal is also used to determine the engine speed.The secondary speed/timing sensor is on the right-hand side of the cylinder block toward the rear of the engine. The secondary speed/timing sensor generates a signal that is related to the camshaft position. The secondary speed/timing sensor detects the movement of the teeth on the timing ring for the camshaft. The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM calculates the speed and the rotational position of the engine by using the signal. The secondary speed/timing sensor is required for starting purposes.During normal operation, the secondary speed/timing sensor is used to determine the cycle that the engine is on. When the timing has been established, the primary speed/timing sensor is then used to determine the engine speed and the angular position.The loss of signal to the primary sensor and/or the secondary sensor will result in one of the following faults:
The engine will continue to run when only one sensor signal is present from either the primary sensor or the secondary sensor.
Loss of signal both sensors during operation of the engine will cause fuel injection to be terminated and the engine will stop.The primary sensor and the secondary sensor are interchangeable components. If a sensor is suspect, the sensors can be exchanged to eliminate a fault. If a secondary sensor is suspect and a replacement secondary sensor is not available, then the primary sensor and the secondary sensor can be exchanged. This exchange will allow testing to determine if the secondary sensor is faulty.Complete the procedure in the order in which the steps are listed.
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn the keyswitch to the OFF position.
B. Inspect the connectors for the speed/timing sensors. Refer to Troubleshooting, "Electrical Connectors - Inspect".
C. Perform a 45 N (10 lb) pull test on each of the wires in the suspect sensor connector and the sensor connections at the ECM.
D. Check the screw for the ECM connector for the correct torque of 6 N m (53 lb in).
E. Check the ground connection on the ECM for abrasions and pinch points.
F. Check the harness for abrasion and pinch points from the suspect sensor to the ECM.
G. Check that the suspect sensor is installed correctly. Check that the suspect sensor is fully seated into the engine.
Loose connection or damaged wire
Result: There is a fault in a connector or the wiring.
Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all the seals are properly in place and ensure that the connectors are correctly coupled.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points.
Proceed to Test Step 2.
2. Check For Active Diagnostic Codes
A. Turn the keyswitch to the OFF position.
B. Connect the electronic service tool to the diagnostic connector.
C. Turn the keyswitch to the ON position. If the engine will start, then run the engine.
D. Use the electronic service tool to monitor active diagnostic codes or recently logged diagnostic codes.
E. Turn the keyswitch to the OFF position.
Diagnostic codes
Result: Diagnostic code 637-11(261-11) is active or recently logged.