Fuel pump won't stop
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Fuel pump won't stop
I've got a 92 (10-91) E-150 4.9 that is stumping me.
Started dieing one day unless I nursed the gas. Check Engine on.
Now fuel pump won't stop and motor runs like it want's to die. Wouldn't start after I got home and a little ether got it chugging,
but again, runs badly. No fuel leaks noticed. Now it starts every time (don't know why it wouldn't that once)
Fuel pressure 50 lbs at key on, around 42 when running.
I've read a lot of posts on this subject here and cannot diagnose it.
Key on; fuel pump doesn't stop.
New pressure regulator (I saw the posts later).
Pump still runs sounding like a sick cat.
Checked fuses and relays, all good.
Switched horn and fuel pump relay (liked that idea thank you)
Replaced filter.
Followed one direction about unplugging PCM, but got no power before or after key was turned.(pump off of course)
Checked battery connections, good, but no power with PCM unplugged.
After looking for ground pin schematic, everything I found on the 92 didn't look like my PCM plug at all and cannot find pictures for the 91.
Cleaned pins and sockets, greased um up and put it all back together. Re-installed battery (PCM was to the left of brake booster, so I had to remove battery) same issues.
Plugged off return line from motor at tank to see if it held pressure or pump would stop, didn't stop ,but sounded better.
Has held 42 lbs for the last couple of hours. Previously lost pressure over night. Will see tomorrow if it held.
Cannot self test with pump running I read.
Never thought it was the fuel pump or PCM, but running out of options.
Any help would be greatly appreciated!
Started dieing one day unless I nursed the gas. Check Engine on.
Now fuel pump won't stop and motor runs like it want's to die. Wouldn't start after I got home and a little ether got it chugging,
but again, runs badly. No fuel leaks noticed. Now it starts every time (don't know why it wouldn't that once)
Fuel pressure 50 lbs at key on, around 42 when running.
I've read a lot of posts on this subject here and cannot diagnose it.
Key on; fuel pump doesn't stop.
New pressure regulator (I saw the posts later).
Pump still runs sounding like a sick cat.
Checked fuses and relays, all good.
Switched horn and fuel pump relay (liked that idea thank you)
Replaced filter.
Followed one direction about unplugging PCM, but got no power before or after key was turned.(pump off of course)
Checked battery connections, good, but no power with PCM unplugged.
After looking for ground pin schematic, everything I found on the 92 didn't look like my PCM plug at all and cannot find pictures for the 91.
Cleaned pins and sockets, greased um up and put it all back together. Re-installed battery (PCM was to the left of brake booster, so I had to remove battery) same issues.
Plugged off return line from motor at tank to see if it held pressure or pump would stop, didn't stop ,but sounded better.
Has held 42 lbs for the last couple of hours. Previously lost pressure over night. Will see tomorrow if it held.
Cannot self test with pump running I read.
Never thought it was the fuel pump or PCM, but running out of options.
Any help would be greatly appreciated!
Laughing Gas
Joined: Oct 2014
Posts: 792
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92 might be OBD1, My 94 is. Did you look for codes since the CEL is on?
My first thought was the relay, even though you swapped it I would still test it/them.
Does the fuel pump stay on all the time with key out of ignition?
My first thought was the relay, even though you swapped it I would still test it/them.
Does the fuel pump stay on all the time with key out of ignition?
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I think it is OBD1
I got nada from the test. I read that the test will not work with the pump running, maybe that's why.
I swapped for a third relay, nothing changed.
The pump only runs with the key on.
I dropped the tank and checked the fuel pump yesterday.The pump bench tested at 20lbs before gas leaked out at the top of the cup.
the strainer had fallen apart and the glue that held it together was all up inside it.
The pump got up to 80lbs with the return plugged before I shut it off and took it out, Dropped pressure overnight again.
With the pump and tank out, the plug is still hot with the key on. so the new pump I ordered likely will do the same
The ECM is all that's left that I can think of that would cause this...I'm still not sure though.
I wish I could find a schematic of that plug to test my grounds and power pins if I knew which was which.
I got nada from the test. I read that the test will not work with the pump running, maybe that's why.
I swapped for a third relay, nothing changed.
The pump only runs with the key on.
I dropped the tank and checked the fuel pump yesterday.The pump bench tested at 20lbs before gas leaked out at the top of the cup.
the strainer had fallen apart and the glue that held it together was all up inside it.
The pump got up to 80lbs with the return plugged before I shut it off and took it out, Dropped pressure overnight again.
With the pump and tank out, the plug is still hot with the key on. so the new pump I ordered likely will do the same
The ECM is all that's left that I can think of that would cause this...I'm still not sure though.
I wish I could find a schematic of that plug to test my grounds and power pins if I knew which was which.
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Thank you subford. I had read other posts of yours in the past on this subject and thought that was the gist.
You seem too knowledgeable about subject to ignore.
This although is not my PCM array. Mine has four rows of pins. This plug I could find, mine I could not.
Maybe I can find an old key and just rewind that clock.
You seem too knowledgeable about subject to ignore.
This although is not my PCM array. Mine has four rows of pins. This plug I could find, mine I could not.
Maybe I can find an old key and just rewind that clock.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
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From: Easton,Ks
The only 4 row PCM 4.9L I know of was in the 1996 F-150 and it was also OBD-II.
Does not sound like you have a stock setup for a 1992 E-series.
Here is the 1996 4.9L PCM pin-out for the F150.
/
Does not sound like you have a stock setup for a 1992 E-series.
Here is the 1996 4.9L PCM pin-out for the F150.
/
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This van is all stock. No rust and everything is original that I have found.
It has less than 100k on it and other than routine maint., doesn't appear to have had any major work.
I also got a detailed file on the work done with receipts.
It has been a joy to work on so far.
Shape wise, it seems like a 2 year old van. I haven't even had trouble wit a rusty bolt yet and being from Iowa, that's saying something. The power distribution box and AC lettering are firstly in French. I haven't researched where it was originally from, but I thought this may have something to do with the discrepancies. Even the fuel tank says 92 inside and the wiring is all original.
Also that year was the last of that run, I had wondered if maybe... I don't know.
I will get a pic of the PCM and plug when I remove them,
Thanks for your help.
It has less than 100k on it and other than routine maint., doesn't appear to have had any major work.
I also got a detailed file on the work done with receipts.
It has been a joy to work on so far.
Shape wise, it seems like a 2 year old van. I haven't even had trouble wit a rusty bolt yet and being from Iowa, that's saying something. The power distribution box and AC lettering are firstly in French. I haven't researched where it was originally from, but I thought this may have something to do with the discrepancies. Even the fuel tank says 92 inside and the wiring is all original.
Also that year was the last of that run, I had wondered if maybe... I don't know.
I will get a pic of the PCM and plug when I remove them,
Thanks for your help.
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OK, so now color me confused. Let alone can't I find a picture or diagram of my PCM, but apparently I have 2 modules that look alike.
Top one has a white plug, bottom a black.
Is this a PCM and a TCM?
If so, which is which and it isn't obvious to me how to extract either.
It occurs to me that maybe I don't even have the right animal. Maybe these are just plugs.
I'm going out to see if I can find something else...
Top one has a white plug, bottom a black.
Is this a PCM and a TCM?
If so, which is which and it isn't obvious to me how to extract either.
It occurs to me that maybe I don't even have the right animal. Maybe these are just plugs.
I'm going out to see if I can find something else...
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OK, color me stupid.
Opened the hood and looked right at it. Never saw it before (it's a van, hard to see anything easily).
I guess my only option is replacement. I could try cleaning it up and plugging it back in...
Think I'll just order another. They're not too costly.
Thanks again!
Opened the hood and looked right at it. Never saw it before (it's a van, hard to see anything easily).
I guess my only option is replacement. I could try cleaning it up and plugging it back in...
Think I'll just order another. They're not too costly.
Thanks again!
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Thanks subford. It doesn't help if I say I'd already seen that diagram. Needless to say I didn't see anything in that spot then.
I'm just a little older and a bit more wise now.
Need to slow down in the learning curves.
I'm just a little older and a bit more wise now.
Need to slow down in the learning curves.
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While I'm on the subject, since I've had the van, it has a "dead spot" when accelerating. Just above idle (so when you're crossing a busy intersection) if the pedal is in just the right spot, the engine will die.
Any ideas?.
Any ideas?.