Random fuel pump loss
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Lead Driver
Joined: Jan 2003
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From: Ohio
Random fuel pump loss
01 F150 4x4 5.4
Randomly in last year you go to start and nothing. Pump does not cycle, truck doesn't start. Then, all of a sudden it fires and runs fine. It will go months or weeks with no problem, then bang.
Don't know the circuitry, but I assume there is a relay that computer fires to turn on pump. I don't think it's pump related as usually they are all or nothing. Anyone have information on this type of problem?
Thanks
Randomly in last year you go to start and nothing. Pump does not cycle, truck doesn't start. Then, all of a sudden it fires and runs fine. It will go months or weeks with no problem, then bang.
Don't know the circuitry, but I assume there is a relay that computer fires to turn on pump. I don't think it's pump related as usually they are all or nothing. Anyone have information on this type of problem?
Thanks
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
Here's the schematic: 2001 F150 5.4 Engine Management.pdf
The fuel pump, the inertial switch, and the FP relay are shown in cell 25-7.
Verify that the CEL works when the fault occurs. If it doesn't, you have a PCM or PCM power problem, not a FP problem.
Steve
The fuel pump, the inertial switch, and the FP relay are shown in cell 25-7.
Verify that the CEL works when the fault occurs. If it doesn't, you have a PCM or PCM power problem, not a FP problem.
Steve
New User
Joined: Dec 2007
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Freightrain/Project/anyone?
My truck (same model, year, etc.) seems to be experiencing the same issues...I have replaced fuel filter and relays. Have checked fuel pressure (a little low but within specs. barely) but to no avail. Am considering the inertial fuel cutoff switch...possibly intermittent. My truck seems to go if I hear (while listening carefully) the fuel pump whirr for a second or two upon turning the key switch. Sometimes I don't and the truck will crank but not fire. This morn I turned the switch back and forth (six to eight times maybe?) from off to run before I heard the pump cycle. Once it did, truck started. So my question is why is the fuel pump intermittent upon start up?
My truck (same model, year, etc.) seems to be experiencing the same issues...I have replaced fuel filter and relays. Have checked fuel pressure (a little low but within specs. barely) but to no avail. Am considering the inertial fuel cutoff switch...possibly intermittent. My truck seems to go if I hear (while listening carefully) the fuel pump whirr for a second or two upon turning the key switch. Sometimes I don't and the truck will crank but not fire. This morn I turned the switch back and forth (six to eight times maybe?) from off to run before I heard the pump cycle. Once it did, truck started. So my question is why is the fuel pump intermittent upon start up?
Thread Starter
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Lead Driver
Joined: Jan 2003
Posts: 9,893
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From: Ohio
Ok, sounds like this is a common issue? At least someone else has typical issue. Truck doesn't quit after running, just won't always start.
I put new relay in it yesterday, pulled old one apart and looks brand new inside, so can't say it was the contacts. I think it's computer related, as not telling it to come on. WHY? Cosmic muffies?
I put new relay in it yesterday, pulled old one apart and looks brand new inside, so can't say it was the contacts. I think it's computer related, as not telling it to come on. WHY? Cosmic muffies?
New User
Joined: Dec 2007
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I'm leaning a little more toward the ignition switch itself right now since cycling that thing seems to get the fuel pump going. Although I noticed that all the voltage goes thru the inertial cut out switch on the way to the pump itself, it doesn't seem logical that it would be intermittent. The truck isn't moving when it's off, and as you have experienced, once it's running, it stays running. May have to try to figure out which switch I need and try that. Since this problem is infrequent, it's hard to tell if a replacement part has made a difference.
G
G
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
Not a common issue. Haven't seen others with the same problem over the last couple of years that I can recall.
CEL = Check Engine Light
Steve
CEL = Check Engine Light
Steve
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Thread Starter
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Lead Driver
Joined: Jan 2003
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From: Ohio
Ya, no codes or CEL here either. Just no pump randomly. Never had to tow it, just keep trying and finally it will start and run fine. Only issue this last time was salesman that had it killed the battery before getting it to start. DOH! I suppose cycling the key and waiting for pump would be better then cranking it til it's dead!
BTW, thanks all for the input and information.
BTW, thanks all for the input and information.
Posting Guru
Joined: Jun 2002
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From: Home, at last!
Well happened to me today on a 2003. Hints of hard starting in the past. 2am this morning on my way to work, I had to crank and crank to start it. Same when I left work. 60 MPH she died on the way home in the middle of the freeway. Waited a moment and she started back up.
Got home and checked the fuel pressure. Just turning the key to start the pump I got 25 PSI. Started her up and revved the engine and the pressure dropped. Oh, the pressure dropped right after the pump cycled, it went from 25 psi to zero in no time.
Fuel pump had been going bad for a while.
Replaced it and problem solved.
Got home and checked the fuel pressure. Just turning the key to start the pump I got 25 PSI. Started her up and revved the engine and the pressure dropped. Oh, the pressure dropped right after the pump cycled, it went from 25 psi to zero in no time.
Fuel pump had been going bad for a while.
Replaced it and problem solved.
