811618 Mercury VALVE ASSEMBY

Illustration 1 g02153893
Components of the water level sensor
(1) Water level sensor
(2) Sensor buffer
(3) 4-pin connector for the sensor
(4) Integral connector at the sensor Water level sensor (1) contains no moving parts. The sensor provides the same function as a switch. The output state of the sensor buffer (2) is dependent on the type of liquid that is detected at the sensor probe. As the level of the water contamination rises above the probe of the sensor, the buffer output changes according to the following conditions:
Table 1
Output States for the Sensor Buffer
Designation of the Output Driver No Water Contamination Water Contamination
Terminal 3 Ground Open circuit
Terminal 4 Ground 5 V The Electronic Control Module (ECM) detects the output at terminal 3 of the sensor buffer in order to determine the state of the sensor. Terminal 4 of the sensor buffer is unused by this application.The sensor must detect water for a minimum of ten seconds before the state of the output drivers will change. The sensor buffer will provide the applicable signal at the outputs for a minimum of 20 seconds after the output transitions.With the sensor probe in air, the correct resistance of the sensor between terminals 1 and 2 at the integral connector is approximately 255,000 Ohms.Caterpillar Electronic Technician (ET) can be used to check the "Fuel/Water Separator Level Status" parameter in order to determine the status for the sensor.The activation of an event code and/or a warning lamp is probably caused by a water contamination in the fuel/water separator bowl. The next likely cause is a problem with the wiring harness, a connector, or the sensor. The least likely cause is a problem with the ECM.
Illustration 2 g02153852
Schematic of the circuit for the fuel/water separator system
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Illustration 3 g02244513
Location of the connectors at the ECM(typical left side engine view)
(5) J1/P1 ECM connector
Thoroughly inspect the sensor connectors (3) and (4), and ECM connectors (5). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 4 g02153897
Terminal locations at the P1 ECM connector for the water level sensor
(P1-56) Water in fuel
Illustration 5 g01635197
Terminal locations at the 4-pin connector for the water level sensor
(Terminal 1) Supply voltage
(Terminal 2) Return
(Terminal 3) Water in fuel
(Terminal 4) Unused
Illustration 6 g01155187
Terminal locations at the integral connector for the water level sensor
(Terminal 1) Sensor reference
(Terminal 2) Sensor reference
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the fuel/water separator system.
Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values. Expected Result:All connectors, pins, and sockets are coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The harnesses and the wiring appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the connectors and/or the wiring.Repair: Repair the wiring and connectors or replace the wiring or the connectors. Ensure that all of the seals are properly connected. Verify that the repair eliminates the problem.STOPTest Step 2. Check the Supply Voltage at the Harness Connector for the Sensor
Disconnect the connector for the sensor buffer at the harness connector.
Restore electrical power to the ECM.
Measure the voltage between terminals 1 (supply) and 2 (return) on the harness side of the connector for the sensor buffer.
Remove electrical power from the ECM. Expected Result:The voltage measurement is between 18 V and 32 V.Results:
OK - The voltage measurement is between 18 V and 32 V. The supply voltage is reaching the sensor. Leave the harness connector disconnected from the sensor buffer. Proceed to Test Step 3.
Not OK - The voltage measurement is not between 18 V and 32 V.Repair: The supply voltage is not reaching the sensor. There is a problem in the circuit for the supply voltage. Check the condition of the fuse in the cab of the machine. If the fuse is blown, replace the fuse. Verify that the repair eliminates the problem.If the fuse os OK, there is a problem in the harness or in a connector between the sensor and the fuse panel. Troubleshoot the circuit and perform the necessary repairs.STOPTest Step 3. Use the "Fuel/Water Seperator Level Status" Parameter to Check for Proper Operation of the Sensor Buffer
Use a wire removal tool to remove the wire from terminal location 3 at the harness connector for the sensor buffer. Ensure that the loose end of the wire does not come into contact with any ground source or power supply.
Connect the harness connectors for the sensor buffer.
Restore electrical power to the ECM.
While an open circuit condition exist