Pathfinder 2002 engine quits at idle

[delvs]

Hi All,

I have a pathfinder 2002 SE having issues with engine quits/stalls at idle. I brought it the dealership and they replaced IAC and re-learnt the sensor. They cannot find anything wrong based on the scanner. Even after the part/s got replaced it still has the same problem after spending $$$$ amount.
I Drove it for few minutes and sure enough the engine quits even at stop light. I also let it idle but after 10-15 minutes the engine will stop. What could be the causing this problem? Any idea?

The service dept. couldn't find it but I'd been telling them that the engine stops/stalls but they said that they cannot duplicate it. I will bring it back for I don't know how many times now.

Anybody has any idea what is going on with my pathy?

Appreciate any input. Thanks

[Towncivilian]

No check engine light? Does it stall when cold, or only when hot?

Try cleaning the MAF sensor. See instructions on the bottom of this post.

Welcome to NICO.

[delvs]

Hi, thanks for the reply.
The MAF is clean and no abnormal code appears. I can re-start again without a problem. It looks like there is no fuel or getting choke after I re-started it.
Could it be in a fuel system? I fuel pump maybe? or a fuel pressure sensor but this will throw codes if it is faulty......

[Towncivilian]

Change your fuel filter, perhaps it's clogged. Guide here.

[delvs]

It has a new fuel filter and the dealership performed a decarb process late last year.
HOw about the relay to the fuel system?

[Towncivilian]

It can be faulty, but usually when relays fail they are either stuck closed or stuck open. You can try replacing it with say, the fog light relay (assuming they are the same colored relay) to see if things improve.

[delvs]

Ok I will try this and will let you know the results.
It's really hard to troubleshoot this because the engine runs smooth and perfect.

[delvs]

Just swapped the relays and the engine is still running after 20 mins and counting. (before the swap the engine stops at idle after 20 minutes.)

Will give update if it stops again.

[delvs]

may I know what this relay do (fuel PumP relay)? Because there is another relay (Fuel Pump 2) on the passenger side.

So far the engine is still running now at 50 minutes. I hope this is it.
I will swap the relay again and see if I can get the problem to show up again.

[Towncivilian]

I'm actually having trouble deciphering the wiring diagram to find out what the second fuel pump relay does, so I can't answer your question. I need to stare at wiring diagrams more.

I hope your problem is solved. It's certainly an easy fix.

[delvs]

I swapped the original relays back and the engine is fine and it did not stop and running now at 30 mins. Looks like this is not the problem.
I will continue to monitor this problem and will post for any progress.
Thanks for the feedback.

Please feel free to get add anything to get this issue resolved.

[Towncivilian]

It's possible there was some dirt or corrosion at the contact points of the relay and the wiring, and swapping relays agitated it off. If things stay working, I guess that would be a valid explanation.

You can try to loosen and retighten ground screws:

[delvs]

Ok thanks.
How about the ECM, do you think it has something to do with this problem?

[Towncivilian]

I highly doubt it.

[delvs]

Ok thanks.
I started it again and so far still going now at 20 mins.
I' still puzzled with this issue. how come no one has ever think about the relay. I've been searching about this problem and no one has ever come up with a relay.
Appreciate it.

[delvs]

Can I ask the dealer to check the ECM or maybe update it?

[Towncivilian]

Sure, but it'll cost you about an hour of reprogramming either way. The only TSB which has ECM reprogramming relates to oxygen sensor codes and will not fix your problem.

[delvs]

I swapped the original relay back and after I drove for a while It happened again.
I brought it back to the dealer and they are puzzled by what is happening on the truck. They said that they re program the ECM and will drive & observe for a day or two. I haven't heard as of yet.
Will post again for any update.'

Thanks.

[Towncivilian]

Okay, good luck! I'm curious to see whether ECM reprogramming will help in this case.

[delvs]

The ECM reprogramming did help and they said that they relearn the IAC again. the engine is now working fine and the idle stays and did not go low at stop. I just got it back and after driving few miles I can tell the difference. the engine is much smoother. I still need to drive for days and see what's gonna happen. Right now it is doing fine. Appreciate the help.

[Towncivilian]

I suppose I was wrong about ECM reprogramming, then. Hope it stays fixed!