Losing Fuel Pressure

[gwayms]

I have a 01 XJ 4.0. Just had the injectors cleaned and it runs a lot better and the check engine light is now staying off. Was getting a misfire code. Anyway now that i put them back it, jeep doesnt want to start. Have to give it some gas to get it going. Did a pressure check. Turn key on goes to about 40-45, then directly back to 0. Any ideas? Fuel pressure reg. Maybe.
Other than that it runs fine.

 

[BIGdaddy]

there's a check valve inline somewhere back near the filter and pump. Prone to failure, and can cause a hard start.

Also sometimes the fittings on the intank pump are smooth rather than flared, allowing the rubber fuel hoses to become dislodged. This happens in the tank.

Fairly easy to remove the pump to check that out I think, since the pump comes out the front wall of the tank, rather than the top of it.

 

[Root Moose]

If the pressure bleeds right away it is likely the check valve in the pump like Brian said.

You didn't say where you are located. If you are in the salt belt check the lines stem to stern to make sure you don't have a leak somewhere. The fuel rail at the engine (the tubey thing that the injectors connect to) can sometimes hide a "pin hole" leak.

 

[lil_red_wagon]

I lean towards what Moose said. I have recently had 2 friends both doin close to the same thing. Both of theirs where fuel pump problems.