95 Exp 4.0 5 spd dies randomly

[63A]

My 95 Explorer 4.0 w/ 5 spd manual trans has approx 100K. Occasionally (once every few months) it will die while I'm driving. No sputtering or other indications- just goes dead. It won't restart until I've let it sit for 10-15 minutes. After that it starts and drives great again. Since it usually happens on the way to work or something similar, I can't do much diagnosing until later when it starts right up again. I will try pull the codes and see if that tells anything but I'm hoping somebody may have some insight.

 

[BrooklynBay]

Welcome to this forum! Does the fuel pump still work when it dies?

 

[63A]

more info

I have not listened for the fuel pump when the problem occurs. Next time it happens, I'll listen for the pump. I did check the fuel pump just now and it is working fine. I checked the diagnostic codes and the only dode stored is 543 "fuel pump monitor circuit shows no power - power/fuel pump circuits"

I'm not sure what that means- any help?

 

[MrShorty]

KOEO or CM code or both? A KOEO 543 indicates that the computer can see a break in the fuel pump circuit. A CM 543 indicates that the fuel pump circuit went open at some time in the past (maybe one or more of those times it stalled?). If it was a CM code, I'd clear CM so that, the next time it stalls, you'll know that it was a "recent" code probably associated with the stalling. Another thing I'd do would be to give the fuel pump circuit a good looking over to see if there are any obvious loose connectors or something that would cause an intermittent in the fuel pump circuit.

 

[63A]

The 543 code is a stored code. The KOEO test shows no current codes. Are there any usual or common places to get a break in the circuit?

 

[MrShorty]

You're new, so I guess you missed the discussion within the last little while where people talked about the problems they've had with the relay socket. I've heard of cases where the relay itself intermittently fails open. On my '92, I had a break in the wire develop between the fuse and the relay. I've also had some issues with my inertia switch/connector going open if the passenger puts his foot on it just right (but that would trigger a CM 542, I think).

If I were to guess, I'd start by checking the relay and it's socket.

 

[63A]

Thanks for the reply. I'll try to find the thread you mentioned.

Where is the relay located? Can I check the relay or is it an inexpensive relay that I can replace to see if that fixes the problem?

 

[MrShorty]

I'm not sure where they put it on the 2nd gen -- I would expect it to be in the power distribution box near the self-test connector.

Yes, you can test the relay. The trouble in your case is that the problem is intermittent. It appears to work correctly most of the time. I think it would be tricky to devise a test that will definitively determine that the relay suddenly and temporarily failed open. The relays aren't expensive, if you feel like it, you could try just replacing it.