Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion.
- Remove the engine cover.
- Properly relieve the fuel system pressure.
- Remove the fuel intake hose from the throttle body and connect fuel system pressure testers C-3292, and C-4749, C-4799B or equivalent, between the fuel filter hose and the throttle body.
- Start the engine and read the gauge; the pressure should be 14.5 psi.
If the fuel pressure is below specifications:
- Install the tester on the fuel filter inlet hose between the fuel filter and the fuel pump.
- Start the engine. If the pressure is now correct, replace the fuel filter. If no change is observed, gently squeeze the return hose. If the pressure increases, replace the pressure regulator. If no change is observed, the problem is either a plugged pump filter sock or a defective fuel pump.
If the pressure is above specifications:
- Remove the fuel return hose from the throttle body. Connect a substitute hose and place the other end of the hose in a clean container.
- Start the engine. If the pressure is now correct, check for a restricted fuel return line. If no change is observed, replace the fuel regulator.