Chart A-7B, Fuel System Diagnosis (Fuel Pressure Check): Notes
When ignition is turned on, ECM will turn on in-tank fuel pump. Fuel pump will stay on as long as engine is cranking or running and ECM is receiving reference pulses. If no reference pulses are received by ECM, ECM will shut off fuel pump about 3 seconds after ignition is turned on or when engine stops.
Fuel pump will deliver fuel to fuel rail and injectors, then to pressure regulator, where the system pressure is controlled to about 23-31 psi (1.6-2.2 kg/cm2 ), depending on engine operating conditions. Excess fuel is then returned to fuel tank.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- Checks to see if fuel system pressure is within specifications.
- This checks fuel feed pipe and hose for leaks.
- This checks for faulty fuel pump or leaky fuel filter.
- This checks for leaky fuel injector, throttle body or for a faulty fuel pressure regulator.
- Checks for restricted fuel feed pipe, restricted fuel filter and faulty fuel pressure regulator.
- Determines if a restricted fuel return line or faulty fuel pressure regulator exists.