Silent Posted December 29, 2005 Share Posted December 29, 2005 not in a z car, but same series, so someone might be able to help my daily driver, a 95 pathfinder se 4x4 jobbie box on wheels thing. is having an issue. when it's cold it runs great, but once it gets up to operating temp or close, it spits, spudders and at thingy below half throttle or 3k rpms throwing no codes. options on what it could be intake manifold gasket leaks o2 sensor mas air injectors. this is my guess, i could be way off, and it could be a bad connection somewhere. dunno. any help would be great Quote Link to comment Share on other sites More sharing options...
mtcookson Posted December 29, 2005 Share Posted December 29, 2005 not likely to be the maf as if that was causing an issue, the ecu is supposed to keep the engine from revving past roughly 2.5k to 3k rpm. another thing that could cause running issues is the coolant temperature sensor. there should be two of them, one for the gauge and one for the ecu. the one for the ecu would be the causing the problems. it should have two contacts whereas the gauge sensor will have one. for it to be acting the way it does, it either must be running too rich, too lean, or a cylinder isn't firing. does black smoke come out at all? if so, its running rich and can be due to too much fuel, not enough air, an ignition misfire, or an injector putting in too much fuel. no black smoke? if its running lean it can be due to not enough fuel, too much air, or an injector isn't putting in enough fuel. when was the last time the distributor cap, rotor, and wires have been replaced? does it sound like the engine is missing (lopy idle, doesn't sound smooth)? since it has issues only when it gets warm the first thing i'd check would probably be the coolant temperature sensor since that is highly affected by engine temp. once that's checked out we can go from there if it doesn't go. hopefully some other guys chime in with their ideas too though so we can try tracing the exact problem. Quote Link to comment Share on other sites More sharing options...
Silent Posted December 30, 2005 Author Share Posted December 30, 2005 im not sure what it's doing exactly. if it's running lean or rich. it does try and bog down, and stuff of thatnature. i may strap it to a dyno this weekend and load test it at the certain rpm range it does it at, and see if it's running lean or rich. my guess was the injectors. but i can check the temp sensor and see if it's being goofy or not, or if it's a loose connection. on the pathy board they were clueless. so i figured id try the z board MT this is Bryan H off maxima.org BTW Quote Link to comment Share on other sites More sharing options...
mtcookson Posted December 30, 2005 Share Posted December 30, 2005 Ahhh, hey man. Small world... wide web eh? If its the injectors you can start by pulling the spark plug wires off. The crappy part is, you need the engine running to tell. Start the engine, then pull one spark plug wire and listen for changes in the way the engine runs. If rpm drops then put the spark plug wire back and check another. If its an injector, or even a plug/wire, when you pull one of the wires and the engine doesn't change at all you've found where the problem is. Have to be careful though. Those things will shock the hell out of you if the wires have any bad spots. Quote Link to comment Share on other sites More sharing options...
RedBeauty84ZX Posted December 30, 2005 Share Posted December 30, 2005 Could be a vacuum leak as well. Quote Link to comment Share on other sites More sharing options...
Silent Posted December 31, 2005 Author Share Posted December 31, 2005 Ahhh' date=' hey man. Small world... wide web eh? If its the injectors you can start by pulling the spark plug wires off. The crappy part is, you need the engine running to tell. Start the engine, then pull one spark plug wire and listen for changes in the way the engine runs. If rpm drops then put the spark plug wire back and check another. If its an injector, or even a plug/wire, when you pull one of the wires and the engine doesn't change at all you've found where the problem is. Have to be careful though. Those things will shock the hell out of you if the wires have any bad spots.[/quote'] yea i know all about being shocked all to hell got shocked by the msd 6al and blaster 2 coil on my 280z. NOT FUN!! i know it has a small manifold leak because i pressure tested the system to 15 psi, and heard a small one{thank god for the DIY dsm boost leak tester} it sounded like it was one one of the front injectors, OR could be the drivers side manifold. dunno i'll check the spark plug injector thingy this weekend and see what i find. but at idle it's fine. other then a slight lope from the after market cams it seems ok. dunno i'll update tomorrow if i find anything. if all else fails i have access to three spare pathys and two motors {complete} for parts yep small world. never knew you had a z. but now i do! Quote Link to comment Share on other sites More sharing options...
mtcookson Posted December 31, 2005 Share Posted December 31, 2005 a vacuum leak could definitely cause some issues but unless it was a pretty big one i wouldn't think it would be causing that big of a problem. although, if it were leaking around an injector those gaskets are big enough that it could cause a pretty big vacuum leak if it was pretty bad. does that VG still have side feed injectors or top feed? Quote Link to comment Share on other sites More sharing options...
Silent Posted January 1, 2006 Author Share Posted January 1, 2006 top feed i think. never pulled em off there, couldn;t tell ya really Quote Link to comment Share on other sites More sharing options...
Silent Posted January 25, 2006 Author Share Posted January 25, 2006 so far, the o2 sensor is brand new {100 some odd dollars later} and the temp sensor works fine {throws code when unplugged} so my last things are injectors, and or manifold leak, again. Quote Link to comment Share on other sites More sharing options...
mtcookson Posted January 26, 2006 Share Posted January 26, 2006 sorry man, i totally missed your last reply. yeah, i did some checking around it looks like the pathy injectors are actually side feed. makes sense being newer. but anyways, the side feed injectors do have a higher chance of leaking compared to top feed. a couple options to check for vacuum leaks (besides my smoking idea... damn i need to quit lol) would be to use either propane or one of those keyboard cleaners. the safer route would be the cleaner stuff. just blow some of it around the intake manifold area and if there is a vacuum leak it will either rev up if using propane or bog if using the cleaner. if its not a vacuum leak then my guess would be an injector(s). now that i think about it, my 91 maxima gxe bogs every once in a while and in an attempt to simulate the bog on my 90 i ran it rich then lean using the s-afc. it did the same thing the 91 did when i ran it lean so that could be the problem. as most of us know, nissan's injectors aren't the greatest so it wouldn't be an odd thing for an injector to be causing the problem. Quote Link to comment Share on other sites More sharing options...
Silent Posted January 26, 2006 Author Share Posted January 26, 2006 ah crap either way i have to pull the upper manifold off demmit! anyways, i guess this gives me an excuse to finisih my port job on the manifolds Quote Link to comment Share on other sites More sharing options...
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