8C - Electric Fuel Pump Pressure Test

8c. Electric Fuel Pump Pressure Test

Purpose:
To determine if electric fuel pump is producing specified pressure.

Electric Fuel Pump Pressure:

Recommended Procedure:
After verifying that there is fuel in the tank, the pump is being powered and there is not a restriction.

Remove the fuel line to the outlet side of the fuel pump. Install Low Fuel Pump Adapter 014-00931-2 or equivalent between the fuel outlet line and the electric fuel pump. Connect test adapter to gauge (160 psi). Run engine at idle and check for leaks from the line to the gauge. Measure pressure with a full load on the engine. If pressure measures below specification (30-80 psi), check fuel regulator valve for debris If OK, replace the electric fuel pump. After replacing fuel pump, re-check fuel pressure to verify that there is not a restriction downstream of the pump causing high fuel pressure, which will cause the pump to fail again.

A stuck-open regulator valve will cause low fuel pressure.

A stuck-closed regulator valve (possibly caused by debris) will cause high fuel pressure for a short time until the pump fails.










Possible Causes:
^ A stuck-open regulator valve will cause low fuel pressure.
^ A stuck-closed regulator valve (possibly caused by debris) will cause high fuel pressure for a short time until the pump fails.
^ A loose fuel line on the suction side of the fuel system can cause air to be ingested into the system and cause low fuel pressure.
^ Electric fuel pump.
^ Fuel pump fuse.
^ Fuel pump relay.
^ Inertia switch.
^ Fuel pump circuit faults.