Chart A-7B, Fuel System Diagnosis (Fuel Pressure Check): Notes

When ignition is turned on, ECM energizes fuel pump relay for 3 seconds, allowing fuel pump operation. If engine is being cranked or is running, fuel pump will continue to operate as long as ECM is receiving ignition reference pulses. If ignition reference pulses are not detected, fuel pump will stop after 3 seconds.

Fuel pump delivers fuel through fuel filter to fuel injector and fuel pressure regulator, where system pressure is controlled at 36-43 psi (248.2-296.5 kPa). Excess fuel returns to fuel tank through fuel return pipe.

1. Checks if fuel pressure is within specification with engine not running.
2. Checks if fuel pressure is within specification with engine idling.
3. Checks for restricted fuel feed pipe, faulty fuel pump or faulty fuel pressure regulator.
4. Checks for leaks at fuel feed pipe and hose connections.
5. Checks for leaks at fuel pump hose-to-fuel pump pipe connections or for a faulty fuel pump.
6. Checks for leakage at fuel injector, a faulty fuel pump or faulty fuel pressure regulator.
7. Checks for internal leaks in fuel tank, a clogged fuel filter, or a restricted fuel feed pipe or hose, or for a faulty fuel pressure regulator.
8. Checks for a faulty fuel pressure regulator.