To check for a sticking pressure regulator, install a pressure gauge on the Compuchek™ fitting in the side of the fuel shutoff valve.

Start cranking the engine.

The pressure gauge must start moving immediately and increase rapidly until the engine fires (approximately 172 kPa [25 psi]). This should take 3 to 5 seconds.

If the pressure gauge does not move or increases very slowly for more than 6 seconds, the regulator plunger is stuck open and will not let pressure build up quickly for a normal start. This can be caused by dirt, rust, or burrs on the plunger, or burrs on the plunger bore.

If the plunger is sticking, the gear pump must be replaced with a new or ReCon® unit. Refer to the OEM service manual.