Diagnostic Instructions
Circuit/System Description
The fuel filter/heater element housing consists of a water separator, a hand prime pump, fuel heater element and a filter element . Fuel passes through the fuel heater, which is operated by a built-in thermostatic switch. The thermostatic switch opens
or closes to turn the heater ON or OFF, depending on temperature. Fuel then passes through the filter and the water coalescer, where the droplets of water in the fuel combine into larger drops that fall into the water reservoir in the filter. When fuel flows
to the fuel injection pump, the fuel is clean and free of water.
Reference Information
Schematic Reference
Engine Controls Schematics
Electrical Information Reference
Circuit/System Testing
Check the Water in Fuel lamp for proper operation. Refer to
Water-in-Fuel Lamp Always On
.
- Turn ON the ignition , with the engine OFF.
- Disconnect the fuel heater connector.
- With the fuel temperature above 21°C (70°F), test for continuity between the ignition 1 voltage terminal and the fuel filter/heater element housing.
⇒ | If continuity was present, the thermostatic switch is stuck ON. Replace the fuel filter/heater element housing. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Fuel Filter Assembly Replacement