Fuel Delivery and Air Induction: Testing and Inspection

Fuel System Diagnosis

Circuit Description
The fuel pump is an in-tank type mounted to a fuel sender assembly. The fuel pump will remain on as long as the engine is cranking or running and the Engine Control Module (ECM) is receiving reference pulses from the crankshaft position (CKP) sensor. If there are no reference pulses, the ECM will turn off the fuel pump two seconds after the ignition switch is turned ON or two seconds after the engine stops running. The fuel pump delivers fuel to the fuel rail and the fuel injectors, where the fuel system pressure is controlled from 379 to 393 kPa (55 to 57 psi) by the fuel pump assembly. The excess fuel is returned to the fuel tank.

WARNING:
^ The fuel system is under pressure. To avoid fuel spillage and the risk of personal injury or fire, it is necessary to relieve the fuel system pressure before disconnecting the fuel lines.
^ Do not pinch or restrict nylon fuel lines to avoid damage that could cause a fuel leak, resulting in possible fire or personal injury.

Step 1 - 7:

Step 8 - 12:

Fuel Pressure Relief Procedure
1. Remove the fuel cap.
2. Remove the fuel pump fuse Ef18 from the engine fuse box.
3. Start the engine and allow the engine to stall.
4. Crank the engine for an additional 10 seconds.