Pathfinder misfire

[JohnDuffy]

We bought a Nissan Pathfinder R50 3.3 LE new in May 2005 and have had it serviced by the Nissan dealer every 3,000 miles from new.  About a year ago it started developing a random misfire and occasionally stalled.  Part of the problem was that it would do it occasionally but then not for weeks or months. The Nissan dealer replaced the distributor but it did not solve the problem.  Three distributors later and the problem was still not solved.  About a month ago, my wife called me as the car would not start and I had to drive out to try to start it which it did.  A couple of weeks later it happened again but we were together in out separate cars and I managed to get it started.  Then last week it stopped again and I went out but could not start the car and it had to be lifted onto a truck and taken to the Nissan dealer.  The coil was replaced.  24 hours later and my wife has rung me and the car again refuses to start.  Fortunately, she is only a few hundred yards from the Nissan dealer.

 

We did try a non-Nissan dealer after the second distributor replacement but there was no improvement.  We have spend a lot of money but the car is worse rather than better and we do not know what to do next.

[Slartibartfast]

Intermittent stuff is always a pain to track down!

 

Sounds like it's gotta be electrical. Check codes if you have the gear, you might get some clues there, though if it was obvious the dealer would probably have worked it out. You might also try wiggling electrical connectors under the hood to see if you can make the engine stall by moving a loose connector. Misfire suggests ignition, but it sounds like most of that's been replaced at this point. I'd want to take a close look at the connectors for those components and make sure they're clean and tight. Also inspect the wiring for any obvious rodent damage, maybe test for power if you can catch it while it's acting up, check ground points, that kind of thing. If the dizzy is losing power or ground, that (AFAIK) would set the same codes as a failing dizzy, and stall the truck just the same; this might explain why the dealer replaced the distributor multiple times, though if the first two didn't fix it, who knows why they thought the third would.

 

Is there any pattern to the breakdowns? When it's cold, when it's hot, when the engine's up to temp, after a heavy rain? Might help for tracking down the cause.

NicoClub has a bunch of factory service manuals hosted here, but they're all for US models AFAIK. The R50 ended in '04 here, and the 3.3 ended in '01, so chances are they don't have the FSM for an '05 R50 with a 3.3. The 2000 US service manual is probably the closest to what you're working with. Hopefully the ignition wiring is the same.

[JohnDuffy]

Thanks.  I have checked all the connections, tried shaking the wires to see if I can get it to misfire without success.  I came across a suggestion that the screw in the back of the distributor rotor arm can come loose and that it needs to be screwed in with Loctite.  It could be that simple.  Trying that today (it's still dark here).

 

It tends only to happen when the car is hot.  Rain or other conditions don't affect it.

[RainGoat]

Not related but if you haven’t done your power valves, you should. It’s a couple $ repair that could save you your engine.
POWER VALVES
http://www.nissanpathfinders.net/forum/topic/17104-threadlocker-on-power-valve-screws-pics/page-1

[JohnDuffy]

Thanks but we have decided that having bought the car 14 years ago and never run a new car for more than 3 years before selling it that, having been so reliable for so many years that, perhaps, the time has come to scrap it and buy a new car.  We would not sell it onto anyone else with the problems we have had over the past year.  Excellent service from Nissan for 13 years but a pity about the last year.  We nearly bought a Toyota Prado.  Maybe next time although my wife (whose car it is) says she would like something smaller.  Unfortunately, most of those are based on a front wheel drive platform which I would never countenance.

[Slartibartfast]

The angle sensor in the dizzy does tend to fail when hot. From what I've read, aftermarket angle sensors don't tend to last long in VGs, but surely the dealer used Nissan parts, right?

 

If it's got the 3.3, it doesn't have power valves, unless Nissan did something truly bizarre.

 

Older rigs do tend to need some wrenching to keep them going, which can be frustrating as hell at times. Good luck whichever way you go.

[JohnDuffy]

Thanks.  I will try that.  I will check with the garage to see if they have replaced it.  They seem to have replaced just about everything else.