no fuel pressure

[ethanrover98]

Hello all,
I'm underneath the truck troubleshooting a no start issue and have a couple of questions......hoping to get her fixed by the morning......

-took my son to the school bus this morning and the truck started and ran for about 30 seconds and died. Wouldn't start afterwards.

-The fuel pump is running, but I only have a dribble at the rail (not enough to move the fuel pressure gage)

-disconnected the fuel line "out" from the pump and hooked up some hose to the outlet fitting and with the pump running it filled up a quart container in no time.

-thought the filter was clogged, but no luck breaking the connections so I don't know if it is clogged or not

-don't have any blown fuses

-have plenty of spark

Is there anything else that would prevent fuel pressure at the rail with the pump operational besides the filter and can the filter be clogged enough to essentially stop fuel flow. (haven't changed it for an embarrassingly long time)

Any help at this late hour would be tremendously appreciated.

Thanks in advance,
Mike

 

[CandiMan]

Is there anything else that would prevent fuel pressure at the rail with the pump operational besides the filter and can the filter be clogged enough to essentially stop fuel flow.

Usually no and yes.

I say usually no because I'm still learning about LR and I don't know if there could be a pre-filter in the tank with the pump. A cloged fuel filter can definately cause low fuel pressure at the rail. Whatever it takes, sounds like you need to replace that filter.

 

[yellowjacket]

My first question, are any of the lines damaged in any way? My second question, did you check the fuel pump relay? The relay might be going bad and is about 20 bucks to replace if that is the problem

 

[WILL.TILLERY]

Possible causes of a fuel-related no start include:
1. A dead fuel pump (could be the pump, pump relay pump fuse or a fault in the pump wiring circuit)

2. A plugged fuel filter

3. Low fuel pressure (weak pump, restricted fuel line, low voltage to the pump)
you state this is not an issue.
If the pump runs and generates normal pressure to the engine, but the engine still does not start, the problem may be:

1. No voltage to the fuel injectors (blown injector fuse or bad relay)

2. No pulse signal to the injectors from the ECU (no crank or cam sensor input to the ECU, or a bad driver circuit in the ECU, or a wiring harness problem)

3. A shorted fuel injector (robs voltage from the other injectors so none will operate)

CHECK your pressure on the rail first and lets go from there.

 

[yellowjacket]

Possible causes of a fuel-related no start include:
1. A dead fuel pump (could be the pump, pump relay pump fuse or a fault in the pump wiring circuit)

2. A plugged fuel filter

3. Low fuel pressure (weak pump, restricted fuel line, low voltage to the pump)
you state this is not an issue.
If the pump runs and generates normal pressure to the engine, but the engine still does not start, the problem may be:

1. No voltage to the fuel injectors (blown injector fuse or bad relay)

2. No pulse signal to the injectors from the ECU (no crank or cam sensor input to the ECU, or a bad driver circuit in the ECU, or a wiring harness problem)

3. A shorted fuel injector (robs voltage from the other injectors so none will operate)

CHECK your pressure on the rail first and lets go from there.

It's always nice to have someone like Mr. Will Tillery on D-web:applause:

 

[taskforce121]

Have you had a lot of rain, or been driving the truck through puddles, etc. cause it sounds like the ECU under the hood may have gotten wet. If so, you need to take it out, dry it off (by taking it apart), then sealing it up, so this doesn't happen again. many threads on this site about sealing and waterproofing an ECU..


phil
67 Series IIA
94 and 97 Disco I

 

[ethanrover98]

Thanks for the replies.....................I rebuit the fuel pump several months ago and upon removal of the pump yesterday I discovered that the hose coming out of the pump had popped off..................it was engaged just enough to move fuel, but under no pressure!! Back up and running!!!! 205,843 miles on the clock so I ain't going bitch about her being down for a day!!!!