BlackBeautyPathy Posted September 12, 2007 Share Posted September 12, 2007 Got a tough one here, looking for whatever help I can find. My 3.5 litre R50 has engine mood swings. It has been in and out of various shops and dealers with no luck other than its "probably a bad computer". There is no engine codes and it has been diagnosed a lot. What happens is this, I call it "Bad Mode" and "Good Mode". Bad Mode -> with a cold engine (minimum of 4 hours of engine cooling time / overnight ), upon starting the engine there is minimal power, it can survive on the road but shes weak (possibly running rich? or / due to the computer thinking its idling causing it to run rich?? i dunno). It will stay like this if you continue to drive it, starting and stopping the engine throughout the day. Good Mode -> full 240 horses, lots of power, engine runs great this mode will only show up if the correct "strange warming up procedure" is carried out: start engine completely cold (bad mode), drive minimum 2 minutes to whatever time in bad mode (as long as the engine is significantly warmed up) THEN it MUST cool for approx. 1 hour - 2 hours. Then start engine and Good Mode will show up for your driving day as long as it doesn't get cooled for more than approx. 3 hours. if so back to bad mode. sorry......that was a lot to take in........anyways, I'm looking into any ideas from anyone, I'm trying to track down someone to repair / flash my computer. Or buy a used or new one..... possibly a 350 z one if thats even possible or a good idea, cause I know they have the same engine guts (VQ35DE). Appreciate any tips !!! Link to comment Share on other sites More sharing options...
csutke Posted September 12, 2007 Share Posted September 12, 2007 (edited) thats the weirdest thing i have ever heard of but thats me. The best place to start your search for a new ECM would be a junk yard or NOW, as to the putting an ECM from a 350Z couldnt tell ya if that is a good idea or not. Edited September 12, 2007 by csutke Link to comment Share on other sites More sharing options...
Jarsiff Posted September 12, 2007 Share Posted September 12, 2007 I doubt the wiring harness would be the same in the z as the pathy besides if there is a difference im sure its tuned differently...as far as the other before you drop coin on the ecm have you done some of the preventitive stuff like tune up and clean the maf maybe? i've never heard that complaint before either but I like to start with the cheaper fixes and work my way up, lol Link to comment Share on other sites More sharing options...
BlackBeautyPathy Posted September 13, 2007 Author Share Posted September 13, 2007 I've done everything. When in Good Mode the engine is mint. The Plugs aren't that old, fuel filter is new, cam sensor, full exhaust and o2 sensors are new, no engine codes. The maf sensor is less than a year old, I'm told its good. I have a weapon R intake, anybody ever run into any issues with that, i doubt its that though. As for the ECM, I can't use one from the 350. I'm gonna start looking at the junkyards, I've heard that I might run into issues with a used computer, because supposedly theres like a few different ones for the pathy 3.5. If anyone knows any ECM repair pros, let me know? Thanks !!!! Link to comment Share on other sites More sharing options...
nissandoms47 Posted September 13, 2007 Share Posted September 13, 2007 (edited) Well maybe its the engine temp sensor or something. If you're computer thinks the engine is overheating. It'll have no power at all and wont rev past a certain limit. On the VG R50s when its at the H it wont rev past 2000 rpms. So just a thought Edited September 13, 2007 by nissandoms47 Link to comment Share on other sites More sharing options...
88pathoffroad Posted September 15, 2007 Share Posted September 15, 2007 Could also be faulty wiring somewhere. One bent pin, or a slightly not-plugged-in-all-the-way connector may intermittently do such a thing. I couldn't say where or which it might be, but a solid go-over of all the underhood engine wiring might be a good project to check into. Link to comment Share on other sites More sharing options...
alkatheeri Posted October 23, 2007 Share Posted October 23, 2007 VQ35DE I had the same problem ,,, The STORY : I fixed a race air filter and every thing was OK, then I washed under the car's hood, then the problem starts .. Bad mode in the morning, good mode in the evening ... I took the car to many places to chek it, and they said that the computer did not show any problem ... one day I removed the switch of the air sensore when the engine was on, then the engine starts vibrating then become off, When I start the engine, the "CHEK ENGINE" lights ... Now I went to the tech. to chek the engine with computer, then he saw the error code and he reset it after I return the original air filter... now my car is in the good mode ... I hope that you get an idea from my story Link to comment Share on other sites More sharing options...
BlackBeautyPathy Posted October 28, 2007 Author Share Posted October 28, 2007 hmmmmm........ I have a weapon R air intake, you think that might be a problem? Link to comment Share on other sites More sharing options...
DucatiDom Posted October 31, 2007 Share Posted October 31, 2007 Been runnin' a WR intake for like 2 years, no problems. Gotten it wet, mud covered, not real careful beyond not swamping the thing. Try unplugging your MAF, and AIT sensors, replug see in problem or a code pops up. GL Link to comment Share on other sites More sharing options...
BlackBeautyPathy Posted November 2, 2007 Author Share Posted November 2, 2007 wheres the Air Intake Temperature Sensor? Link to comment Share on other sites More sharing options...
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