abertooth Posted December 5, 2014 Share Posted December 5, 2014 Hi everyone. This is my first post here. I've read every thread that is even closely related to my problem on this site and other sites to be sure that I haven't missed something. I have a 91 Pathfinder that is in beautiful condition with 175,000 original miles on it that I recently purchased in august. This problem came on suddenly a few weeks ago. Truck starts strong with no problem when cold. I'll take it out and drive it and once it reaches running temp (about 10 minutes or so) it will start to sputter and lurch. I'm able to limp it home and park it. If I let it keep running it will eventually die. It will not start back up until it has cooled. Timing belt was changed about 30,000 miles ago. Other than that I don't have much information about the previous maintenance, though seeing its condition it would be hard to believe that it wasn't maintained regularly. I pulled the ECU codes and it is giving me #21 which relates to "Ignition Signal". From my research on this, I was led in the direction of Ignition Coil and Ignition Control Module. I replaced both with no positive result. Other threads that I've read mentioned various sensors (MAF, Coolant Temp, etc.). I think my best piece of information here is that everything runs great until it reaches temp. It feels to me like the engine may be flooding itself. Could this have something to do with the injectors not getting a signal that the vehicle has reached running temp and to adjust the fuel mixture? If so, would this signal be coming from the MAF or Coolant temp sensor? Please let me know if anyone has had this same problem or if you have any thoughts on the matter. Thanks! Link to comment Share on other sites More sharing options...
gv280z Posted December 5, 2014 Share Posted December 5, 2014 Are you getting black smoke and the engine sputtering around 2 or 300 rpm? Does it die when you're braking or slowing to turn? What you're experiencing sounds very similar to what a LOT of people have to deal with at some point. For me it was the Gunk fuel service at Kwik Kar with a vacuum line 20 min iv drip that cured my ailing IACV aka idle air control valve. Ever since then it never came back. Link to comment Share on other sites More sharing options...
ebayfish Posted December 5, 2014 Share Posted December 5, 2014 Have you changed your fuel filter? Check/replace your plugs, wires & your O2 sensor(unplug it at the harness & see if it drives better). Run Seafoam in your gas & your crank case 100-200 miles before your next oil change. Make sure you have a clean air filter. Other than that, do you know its in time? Link to comment Share on other sites More sharing options...
abertooth Posted December 5, 2014 Author Share Posted December 5, 2014 Hi guys, thanks for the replies. To answer your questions: No it doesn't die when braking or slowing to turn, no black smoke. It will keep running but get very low power and some sputter and it gradually gets worse. I am not sure its in time. It had a timing belt service not too long ago. I guess it could have gone out of time but it started very suddenly. What could cause it to go out of time suddenly like that? Are you talking about the O2 sensor before the Cat? What gets me is that it runs great until it reaches temp. I feel like if it were the plugs and/or wires or the timing, it would show signs all of the time and when starting. Link to comment Share on other sites More sharing options...
adamzan Posted December 6, 2014 Share Posted December 6, 2014 If it runs fine cold then acts up hot, most likely a sensor. I'm betting o2 or the coolant temperature sensor. There is only one o2 sensor on these. Link to comment Share on other sites More sharing options...
abertooth Posted December 6, 2014 Author Share Posted December 6, 2014 If it runs fine cold then acts up hot, most likely a sensor. I'm betting o2 or the coolant temperature sensor. There is only one o2 sensor on these. Hi adamzan, I've read a lot of your posts on my journey through the EF and EC systems of this thing. Thanks for your thoughts. I have a coolant temp sensor coming in the morning. Fingers crossed that I get out of this with a $15 part. Today I checked some of the plugs to look for information that way. I also checked that the MAF was working. All good there. Verified that all vacuum hoses are in good condition. Cleared any codes from the ECU and took it out for a ride to get it to run rough and see if it threw a new code. It ran rough, didn't like high RPMs when I stepped on it and it gradually deteriorated to just sputtering enough to get home. Some observations from the test ride: It started and ran great cold as usual, as it got warmer, it liked high RPMs less and less until I had almost no power. As the performance got worse I got some small backfires and then legitimate sputtering (just enough power to get it parked). The Tach was also jumping around once it got real bad. It definitely felt like it was misfiring. From some of the things that I read it sounds like the Camshaft Position Sensor could have a part in this. What's your take on this? Link to comment Share on other sites More sharing options...
gv280z Posted December 6, 2014 Share Posted December 6, 2014 Abertooth, for some reason, call it instinct or whatever, after reading your last post something new occured to me, have you considered that you may have 1 or 2 clogged catalytic converters? If you were to go to a muffler shop like a meineke or somewhere like that, I bet they wouldn't charge much just to cut out the cats to inspect them and see how bad they are, if they're not in bad condition, they'll just weld 'em back in, probably cost 20 or 30 bucks in labor. They shouldn't balk at that, it's not illegal to take a cat out and look inside it, it's not like you asking them to delete it or anything. Link to comment Share on other sites More sharing options...
ebayfish Posted December 6, 2014 Share Posted December 6, 2014 Both cats can be unbolted to inspect, no need to go to a shop & have them cut & welded. You can annoy your neighbors & unbolt them, drive around tour neighborhood & see if it corrects the problem. You can also get a pipe from Nissan or a junkyard to delete your first cat if you'd like. As mentioned before, try unplugging your o2 sensor & driving. That instantly told me mine was faulty, I got a new NGK on eBay for $15. The harness is located on the passenger fender. 1 Link to comment Share on other sites More sharing options...
Slartibartfast Posted December 6, 2014 Share Posted December 6, 2014 This doesn't sound like a cat to me--a clogged cat wouldn't be temperature related, right? Not liking higher revs would make sense, but only if it did it constantly--the fact that it's alright when it's cold says you're on the right track looking at bad sensors. Link to comment Share on other sites More sharing options...
abertooth Posted December 6, 2014 Author Share Posted December 6, 2014 So, today I swapped out the coolant temp sensor because it was a cheap part not really worth my time to test the old one. Checked continuity in the harness. Seemed fine. Took it for a spin and it did the same old dance. Limped it home. No new codes. Went for a ski while it cooled down, went back to start it again and it ran like crap. Started rough, low idle, jumpy tach. It seems like it may be getting progressively worse all around. Next I'm going to test the O2 sensor. Up here at 10,000 feet we only get a couple good hours per day to work outside before the temp drops, so I basically get one thing tested per day. Kind of frustrating. Can anybody tell me which harness on the passenger fender is the one for the O2 sensor? Also, digging out my infrared thermometer to test the cat tomorrow. I would agree with slartibartfast that it didn't seem like a cat problem but its a pretty quick test so i'll check it anyway. Thanks for your comments everybody! Link to comment Share on other sites More sharing options...
ebayfish Posted December 7, 2014 Share Posted December 7, 2014 There are two or three grey harnesses on a tree on the pass fender. Its the lowest one if I remember, leading with 3 wires. O2 sensors measure the ratio between exhaust & atmospheric oxygen. Where you are, the oxygen is already low, which could screw with it even more. Link to comment Share on other sites More sharing options...
adamzan Posted December 7, 2014 Share Posted December 7, 2014 Its the one with two white wires and one black. Or vice versa. I can't remember. Link to comment Share on other sites More sharing options...
ebayfish Posted December 7, 2014 Share Posted December 7, 2014 One is your o2 the other is speedometer, unplug one & see if your speedometer still works, if not, unplug the other. Link to comment Share on other sites More sharing options...
ethanrobinson1203242 Posted January 31, 2015 Share Posted January 31, 2015 At low idle it's running rough then after a few minutes it will eventionally die... but at about 1800rpm and running dow the road it runs fine. New fuel filter, air filter, plugs,wire, distributors cap rotor clean the mass air flow sensor clean the screen out check for vacuum leaks can't find any that I'm aware of. Thinkin o2 sensor next but thought I'd see if any advise Link to comment Share on other sites More sharing options...
ethanrobinson1203242 Posted January 31, 2015 Share Posted January 31, 2015 At low idle it's running rough then after a few minutes it will eventionally die... but at about 1800rpm and running dow the road it runs fine. New fuel filter, air filter, plugs,wire, distributors cap rotor clean the mass air flow sensor clean the screen out check for vacuum leaks can't find any that I'm aware of. Thinkin o2 sensor next but thought I'd see if any advise Link to comment Share on other sites More sharing options...
SpecialWarr Posted January 31, 2015 Share Posted January 31, 2015 Just a thought: (and I don't even know that this might be able to fix anything) did you change the vacuum hose from the top of the Fuel Pressure Regulator to the air plenum? If it's got 175 000 miles it may be cracked and tired. The FPR is located on the back of the intake plenum right next to the firewall and has about 4" of 3/32" vac hose on it which goes from the FPR to the plenum.... and its the thing that gets in the way of changing / finding / removing / installing the plug and ignition wire on cylinder #6...... Just a thought. Link to comment Share on other sites More sharing options...
ethanrobinson1203242 Posted February 1, 2015 Share Posted February 1, 2015 I'll c heck it out off the top of my head I do remember it being weather checked Link to comment Share on other sites More sharing options...
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