# 1999 Pathfinder Stalls/Dies



## mosstowel (Sep 6, 2012)

I have a 1999 Pathfinder Chilkoot that sometimes runs fine for varying lengths of time - other times it won't start at all or just quits on me when driving (as if it ran out of gas). I had a mechanic look at it who ran a diagnostic and identified the distributor as the issue, so I had that replaced. After the distributor was replaced, everything seemed to run fine for about two weeks. At this point, I started experiencing the same problem again. I brought it back to the mechanic who told me the diagnostic now said the PCM was the issue. The mechanic didn't have any PCMs available to him, so I haven't had any other work done.

I also had a similar problem about 2 years ago, which resulted in a new fuel pump and PCM. The fuel pump seemed to make no difference, but the vehicle seemed to run fine once the PCM was replaced, until now.

Does anyone have any advice? Should I replace the PCM (the mechanic doesn't seem very confident this will fix the problem)? If so, where is a good place to order one (I'll be shipping to Canada)? Is this a part I can service myself?


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## dhadder1 (Jan 22, 2012)

I got an 05 but it just started doing this sparaticly. Happened first when I was about to go on a work trip. It gave a code that said it was the camshaft position sensor. It has done it about 10 times since then but it does not give a code anymore. Mine will spit and sputter then die sometimes it will sputter through it and stay running but if it dies it always fires right back up. Sometimes it will die right away again. I replaced the camshaft position sensor about a year ago and it was a completely different type of problem. It was mainly a problem with the starting of it


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## smj999smj (Jan 1, 2006)

It sounds more like a dirty or faulty IACV-AAC valve than a PCM issue. Nissan ECM/PCM's are pretty reliable on the whole and it's rare to see them fail. I would suggest getting a can of throttle body cleaner or carb cleaner and cleaning out the throttle body. As you turn the throttle plate, look for a small hole on the bottom, inside of the throttle body. Spray some cleaner into that hole, as well. Start the engine and let it run for a few minutes. Adjusted the based idle per the FSM procedure, which includes warming up the vehicle, shutting it off, unplugging the TPS, starting engine and adjusting the idle, shutting off and reconnecting the TPS. If that doesn't work, you could try removing the IACV-AAC valve and cleaning that out, but I would replace it, if it were mine. The reason I suggest this is that the IACV-AAC valve is the part that is responsible for controling an unmetered air passage that is used to control fast idle cold start as well as help maintain proper idle under various loads placed on the engine (A/C, P/S, etc.). VG33E's are fairly well known for varnish developing inside the throttle body and on the throttle place and it's not unheard of for the IACV-AAC valve to get dirty, too. At this point, the only reason I would condemn the PCM is if it were to fail a "tap test," where tapping on the PCM causes the engine to "stutter" or act up, or if there is confirmed proof that the PCM is bad. Another common problem on the VG33E, although I don't necessarily think it's related to your current problem, is dirty fuel injectors. A professional fuel injection service should be performed on these engines every now and then...maybe once every 45000-60000 miles. 
If you are convinced that a PCM replacement is necessary, the only PCM I would feel confident in using is a genuine Nissan reman. unit. If you want the cheaper alternative, check out Rockauto.com. They usually have the best prices, wide selection and they ship to Canada (they're based out of Wisconsin in the USA).


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## mosstowel (Sep 6, 2012)

Alright, well I have yet to fix this vehicle. The fuel injection relay was replaced a few years ago. The fuel pump was replaced less than two years ago, the ECU was also replaced (with a used one) at this time. A few days ago I took it in to Nissan to have two recalls done - one installed a new fuel filter neck, hoses, clamps, bolts, and clips, the other had an anti-corrosion seal applied to the strut housing. As mentioned above, the distributor was recently replaced, the problem still persists, and a non-Nissan mechanic said my ECU is the issue.

I'm not sure what I'm going to do at this point since I have received rather varied advice from people I've consulted. I could take it in to Nissan, but I'm not so sure I want to spend more money. 

If I were to replace the ECU, is it something I can do myself? Other than being a huge pain in the ass to access, are there other issues I'd run into? I don't have a special key or anything that would need programming, so would it just be plug and go?


> the only reason I would condemn the PCM is if it were to fail a "tap test," where tapping on the PCM causes the engine to "stutter" or act up


It seems to pass the tap test, I guess.


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## smj999smj (Jan 1, 2006)

ECM for that year should be plug and play if you don't have an immobilizer system. A new ECM from Nissan is around $1000. A better option...or at least a cheaper option...would be to send it to a company that does ECM repairs. I've heard some people use these guys with good results:

Circuit Board Repair - Ford 6.0 FICM Repair | Circuit Board Medics


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## mosstowel (Sep 6, 2012)

I guess I didn't write a very good description of my issue in the OP. As mentioned above, the vehicle runs fine for varying lengths of time - other times it won't start at all or just quits on me when driving (as if it ran out of gas). Sometimes the vehicle is difficult to start, and the idle speed is erratic at times. If the vehicle starts, it usually only runs for about 10 km or so. It seems to have more trouble starting if it was driven recently.


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## smj999smj (Jan 1, 2006)

You'll have to do some diagnostic work. Are there any current stored trouble codes? When it stalls and won't start, you'll need to confirm spark to the plugs and proper fuel pressure.


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## mosstowel (Sep 6, 2012)

There are likely some error codes currently, but I don't know what they are. All I know is the mechanic said the ECU needed to be replaced... but he couldn't tell me the code(s) because he kept no record of them. Maybe it's best I bring it in to a new mechanic. The guy I normally see has been off work for quite some time due to family issues and I've been waiting a long time for him to return.


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## mosstowel (Sep 6, 2012)

So I brought the vehicle into a Nissan dealership to have their mechanic look at the vehicle. Like the previous mechanic, he ran the diagnostic which indicated the ECU needed to be replaced. So, I had the ECU replaced with a used part. Now the vehicle would not start at all and I was told to replace the mass air flow censor, which I did (again with a used part). The vehicle now starts when cold, but shuts down and will not start when warm. I have been told it is likely a soft connection which loses connection when it warms up, but they currently aren't sure of anything beyond that. They said they were going to look into the Nissan database (or something) and see if they could find any similar issues to use as a reference as they are stumped at the moment. I'm currently waiting for their response.


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## Glamisman (Feb 12, 2016)

*1999 Pathfinder Stalls, harse upshifts, poor throttle "feel" under 2500 rpm*

Forgive me posting to a 3 year old post... I just acquired a 175k 99 Pathfinder in a non-op state... $100. Putting in a new distributor fixed the no start condition and during the analysis test drives lots of M.I.L. codes popped up. None of them really made any sense, Bank 2 too lean, multiple misfires, knock sensor 2 bad. The trans shifted very hard and there was a sluggish throttle responce below 2500 rpm. Not having access to any diagnostic equipment other than a multi meter a factory manual and common sense I proceeded to check things out. The air boot closest to the throttle body was split so I started there, an improvement in drivability but still not smooth. I went to the wrecking yard and acquired a complete air intake system with MAP sensor for $75. Swap in the wrecking yard MAP sensor and yet another small drivablity improvement. During this test drive I noticed that if I slowly opened the throttle the motor responded one way but if I opened it fast the responce was much better. Ok I think the throttle switch/throttle potentiometer is flaky. $30 on line for a new switch / potentiometer. I sat down a read the manual on how to install it and I learned quite a bit. The installation of the switch / potentiometer has to be done according to the manual, you can't guess at it. You might get lucky but I doubt it. There is a .05 mm tolereance on throttle position to get it right or getting it wrong. While I was fiddling with things warming up the vehicle I noticed after it got warm that the idle would wonder from almost stalling to a medium fast idle... vacuum leak or I.A.V. is what I thought of. I hooked my vacuum pump to the throttle positioner and pulled 22 inches of vacuum on the throttle positioner and the idle smoothed down. As the vacuum pump bleed off vacuum the idle started to climb, then go down, then climb again. I pulled 22 inches of vacuum again and the idle smoothed out again, until the vacuum blead off again. I took a real close look at the throttle positioner and sure enough, I could see it moving the throttle valve ever so slightly. The movement range on this positioner is some 3 mm and apparently there is enough spring force to move the throttle just enough to kick the idle switch to the wrong position. 
For those interested in the proper proceedure for setting up the a 99 Pathfinder idle switch/potentiometer it is as follows:

engine has to be warm enough for the fast idle roller to be off the fast idle cam. I visualy check to see that the steel roller that rides on the fast idle cam spins freely. 
You will need a .30 and a .35 mm feeler gauge, a hand opperated vacuum pump, a multimeter (analog or digital) a couple of small insulated alligator clipped jumper leads.
pull some vacuum on the idle poisoner and verify that there is clearance between the positioner and the throttle tab. 
Set your meter to ohms and a 2k range is good enough.
take the top connector off of the switch and put one clip on the top prong and the second on the middle prong.
put the .3 mm feeler guage between the throttle stop and the throttle stop tab and check to see if there is continuity, 0 resistance and verify that the vacuum has not bleed off the position switch, if so, pull more vacuum.
remove the .3mm feeler gauge and insert the .35 mm feeler gauge. Verify there throttle positioner is not touching the throttle tab and there should be an open reading, out of range etc. on your ohm meter. If not rotate the switch/potetiometer slightly until it is "open". Recheck the throttle positioner is off the throttle tab and insert the .3 mm feeler gauge and see if it is now showing 0 resistance or closed. You might have to fiddle with this a few times... just tighteneing the adjusting screws can throw it off. 
Take it for a test drive and you should notice a big improvement in drivability AND less harshness in the upshifts. 
More test drives will confirm that the idle switch/potenetiometer was the root cause of all of the M.I.L. codes, if not, I will do more digging.


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## Glamisman (Feb 12, 2016)

addendum to my above post. I was still not "happy" with the up-shifting and I figured that I would address this at a later date, well it is later. I noticed that I would have to push forward on the shift lever just a little to get the ignition interlock to allow me to fully turn the key to the off position to remove it. I removed / loosened the shifter cover and lengthened the shifter cable so that i would not have to force the interlock to release and took her for a drive... a noticable improvement in reduction of up-shift harshness... not sure if this actually does wnything in the trans valve body or not or if it is just wishful thinking.


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## Tracy128 (Nov 28, 2017)

Sorry to jump on your post but I have a 2008 2.5 pathfinder which loses throttle intermittently and keeps dying when Oslo g or being driven, it has no codes on machine and so frustrated I don't know where to start ?, hopefully one of you lovely people can help


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