2002 Intermittent Fuel Pump
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2002 Intermittent Fuel Pump
In the last 18 months, at random, the truck will not start because the fuel pump does not run (normal operation turn ignition to run, hear the fuel pump; failure mode: silence). The truck has never stopped running, once it is on, it's on, it just won't start sometimes. It is not dependent on weather/temperature; it sometimes will happen twice in a day, and sometimes it will be fine for months. It has stranded me at home and in parking lots, BUT if I wait for 30 minutes to 2 hours, and try again the fuel pump will run (when I turn the key to run) and the truck will start. Which I find weird because sometimes it will not start at home, where it has been sitting unused for multiple days.
One side note, related or not. Years ago I used this truck to teach my daughter how to drive a manual. When she would lurch it bad enough to stall it, it would not restart unless it sat for 10+ minutes. It only happened a few times and I have no idea if the fuel pump was working or not during that period 5 years ago (I just knew it had to sit for 10+ minutes and we were good to go). The fuel pump inertia switch never needed resetting.
2002 F350 5.4L 6spd 85,000
One side note, related or not. Years ago I used this truck to teach my daughter how to drive a manual. When she would lurch it bad enough to stall it, it would not restart unless it sat for 10+ minutes. It only happened a few times and I have no idea if the fuel pump was working or not during that period 5 years ago (I just knew it had to sit for 10+ minutes and we were good to go). The fuel pump inertia switch never needed resetting.
2002 F350 5.4L 6spd 85,000
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From: IL
At 85,000 miles I wouldn't be surprised if the pumps could be on it's way out, but the way you're describing it, it sounds more like a loose connection, maybe a weak ground?
I was going to suggest maybe a filter becoming clogged but reread your post and see that you state the fuel pump does not run, so with that being said I would suggest looking at the wiring check the connection for fraying or corrosion, if that doesn't get the problem solved then I would think a new pump would do it.
I was going to suggest maybe a filter becoming clogged but reread your post and see that you state the fuel pump does not run, so with that being said I would suggest looking at the wiring check the connection for fraying or corrosion, if that doesn't get the problem solved then I would think a new pump would do it.
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At 85,000 miles I wouldn't be surprised if the pumps could be on it's way out, but the way you're describing it, it sounds more like a loose connection, maybe a weak ground?
I was going to suggest maybe a filter becoming clogged but reread your post and see that you state the fuel pump does not run, so with that being said I would suggest looking at the wiring check the connection for fraying or corrosion, if that doesn't get the problem solved then I would think a new pump would do it.
I was going to suggest maybe a filter becoming clogged but reread your post and see that you state the fuel pump does not run, so with that being said I would suggest looking at the wiring check the connection for fraying or corrosion, if that doesn't get the problem solved then I would think a new pump would do it.
Thanks for your insight.
I would just shotgun the pump if it was not a major hassle (drop the tank or remove the bed on a 19 year old rusty truck) AND that everytime I have replaced a fuel pump I have had to do it twice (so if I continue to have problems, I won't know if it is the new pump, or the old problem).
I have been through the entire harness and plugs (interestingly, it does not fully conform to the schematic). I have been suspecting the ground, just not sure which one it is, and all I have found look/test good. I should just add a ground close to the pump until I can figure this out. I did add some test points along the harness so during a failure I can see if it is the harness or the relay or the logic. If it is any of those, I can manually run the pump to start it.
Tuned
Joined: Apr 2001
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I know yours isn't a V10, but there are several threads on this in the V10 forum. Most likely the same issue(s). Could be the pump, but probably the relay. The relay on your 02 is a small relay soldered to the back of the fuse block. You can't replace that (not easily anyway) and so will have to do a bypass. I have a thread in the V10 forum explaining how I did it and another member added pics to the thread from when he did it. I found the best place to test if it is the relay is in the harness going into the cutoff switch under the passenger kick panel. I can't remember the wire color right now, I'll look it up later, but I think I laid that out in the thread I mentioned.
If it is the relay, I would go ahead and replace the pump too. It's not that hard, just drop the tank and swap it out. I think the bad relay ends up frying the pump or maybe a failing pump fries that little relay. Either way, after bypassing the relay on mine and solving the intermittent stalling problem, the pump eventually failed too.
If it is the relay, I would go ahead and replace the pump too. It's not that hard, just drop the tank and swap it out. I think the bad relay ends up frying the pump or maybe a failing pump fries that little relay. Either way, after bypassing the relay on mine and solving the intermittent stalling problem, the pump eventually failed too.
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I know yours isn't a V10, but there are several threads on this in the V10 forum. Most likely the same issue(s). Could be the pump, but probably the relay. The relay on your 02 is a small relay soldered to the back of the fuse block. You can't replace that (not easily anyway) and so will have to do a bypass. I have a thread in the V10 forum explaining how I did it and another member added pics to the thread from when he did it. I found the best place to test if it is the relay is in the harness going into the cutoff switch under the passenger kick panel. I can't remember the wire color right now, I'll look it up later, but I think I laid that out in the thread I mentioned.
If it is the relay, I would go ahead and replace the pump too. It's not that hard, just drop the tank and swap it out. I think the bad relay ends up frying the pump or maybe a failing pump fries that little relay. Either way, after bypassing the relay on mine and solving the intermittent stalling problem, the pump eventually failed too.
If it is the relay, I would go ahead and replace the pump too. It's not that hard, just drop the tank and swap it out. I think the bad relay ends up frying the pump or maybe a failing pump fries that little relay. Either way, after bypassing the relay on mine and solving the intermittent stalling problem, the pump eventually failed too.
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I know yours isn't a V10, but there are several threads on this in the V10 forum. Most likely the same issue(s). Could be the pump, but probably the relay. The relay on your 02 is a small relay soldered to the back of the fuse block. You can't replace that (not easily anyway) and so will have to do a bypass. I have a thread in the V10 forum explaining how I did it and another member added pics to the thread from when he did it. I found the best place to test if it is the relay is in the harness going into the cutoff switch under the passenger kick panel. I can't remember the wire color right now, I'll look it up later, but I think I laid that out in the thread I mentioned.
If it is the relay, I would go ahead and replace the pump too. It's not that hard, just drop the tank and swap it out. I think the bad relay ends up frying the pump or maybe a failing pump fries that little relay. Either way, after bypassing the relay on mine and solving the intermittent stalling problem, the pump eventually failed too.
If it is the relay, I would go ahead and replace the pump too. It's not that hard, just drop the tank and swap it out. I think the bad relay ends up frying the pump or maybe a failing pump fries that little relay. Either way, after bypassing the relay on mine and solving the intermittent stalling problem, the pump eventually failed too.
I have installed some test points to find out which side the failure is (control or pump). I have been through the harness several times, I can say for sure the color of the wire from the relay to the inertia switch is DG/YE and from there to the pump is PK/BK. I also set it up if it is the relay I can bypass it until I can fix it.
I agree that replacing the relay and the pump at the same time is the best shotgun, and as I am getting confirmation that others have had success with doing that I am leaning towards it. I just hate guessing/not knowing. Plus I have replaced fuel pumps that have subsequently failed. So if I replace fuel pump and the relay and I have the problem again now I will not know if the new pump failed, the new relay failed, or neither was the original problem. But I overthink.
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Update, sort of
On the off chance this information is helpful to someone in the future. It has been over 8 months since I asked the question. I have neither replaced nor repaired anything, but I have changed my starting habits. In the past I would turn the ignition to run, then attempt to start the engine. When I would do that, the fuel pump would run, build pressure and stop. The fuel pump would not run again until turning the ignition to start (except when it would not start because the fuel pump didn't run as it was supposed to).
At this point, because of no failure, I suspect either the logic that actives the relay, or the relay itself (unless there is a pressure switch I don't know about). I will continue to start the truck this way to help gather data if it does fail again. I have tapped test points from the relay to the pump at every point there is a possible failure point.
I will update if I learn anything. If I don't update, that means it is still working (with the current starting procedure).
At this point, because of no failure, I suspect either the logic that actives the relay, or the relay itself (unless there is a pressure switch I don't know about). I will continue to start the truck this way to help gather data if it does fail again. I have tapped test points from the relay to the pump at every point there is a possible failure point.
I will update if I learn anything. If I don't update, that means it is still working (with the current starting procedure).
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