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Idle issue, misfires on boost, operating temps?

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  • Idle issue, misfires on boost, operating temps?

    Hey guys, 2 more things that have gone wrong my other R32 that I'm sure have been discussed but I just want to see what you all have to say.

    Since day one, this car has had an issue where when the car has the clutch pushed in as its coming to a stop it stalls out. If the car is revved high at a stand still the revs will just drop down and stall out. This does make the car extremely annoying to drive but I've just put up with it since I just make sure the car is near 1.5K RPM before I clutch in. From what I've been reading this is a Idle Air Control valve issue? or TPS?

    Another issue I have recently is that while your on the move, if you hit the gas and wait for the turbo lag, once the turbo spools it feels like the car hesitates then begins misfiring. I've changed plugs and tightened the gap, cleaned up the coils and applied the dielectric silicone to them and still nothing. Just a few days ago after lagging it would spool and pull very very hard so it was almost like this happened over night. Also worth mentioning the car felt like it misfired/rough in the morning when I would pull out of my driveway, but would go away once warmed up/

    Oil Temps! What should they be? My car stays at 70c, even the Greddy gauge says 70c. I pulled the sensor out and put it in boiling water and its definitely working. Car has a Trust Oil Cooler fitted to it so could that be why the temps are barely registering over 70c? My water temp is right in the middle of the gauge while all this goes on and it doesn't move unless I run it harder than normal.

    The car does have twin TD06's and theres been alot done to it back in Japan so I'm kinda stuck uncovering things as I go along...
    Had a few GTR's here and there..

  • #2
    First issue is the TPS is most likely not on the idle contact, thus the ECU is not kicking up the rpm to prevent engine from stalling. Adjusting TPS requires Nissan's Consult (diagnostic tool) or Consult software, Consult cable if that is not available. The software has a virtual button which should light up when on idle contact while adjusting TPS. If have an aftermarket ECU it should have it's own way to set TPS in the tuning software.

    Second issue sounds like one coilpack is leaking (had the same issue not long ago) which can cause a slight lag at lower rpm. Grey tracking marks near mounting bracket give away that the coilpack is leaking. Sometimes it can be the ignition module that fails to fire one cylinder (common). Replacing ignition module with a good working ignition module eliminates that. Coilpack loom, injector loom are the other causes of missfiring (old, brittle, goes hard which means it needs to be replaced).

    Another could be one of the MAF's could be getting 2x airsources and is similar to a coilpack missfiring. Tighten intake hose clamp just behind MAF's and look for cracks in intake piping.

    Sometimes it's as simple as a intake airleak in intake piping near FMIC.

    Oil temps should be ideally around 80-90 degrees C which is normal for a stock engine. With a modified engine you would see over 100 degrees C on a racetrack. Fitting a high temp thermostat in sandwich plate on engine can raise the point where it should be at for street use, but it's probably set for racetrack use, so I would leave it alone if do sport driving or long trips.

    Stock coolant temp gauge only raises to the top when overheating. Middle (or just above) is normal with stock thermostat. Just under middle at idle is normal with a low temp thermostat (Nismo or similar), which would indicate it's setup for racetrack use or high hp.

    I would fit an aftermarket coolant temp gauge, as the factory coolant temp gauge doesn't give accurate readings (in degrees C).
    Last edited by Skym; 01-10-2015, 05:10 AM.
    RESPONSE MONSTER

    The most epic signature ever "epic".

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    • #3
      Wow this is such a huge start, thank you

      So much on this car has been altered its hard to trace anything, the TPS wiring looks like its been cut and moved around so I'll have to see what the issue is.

      The coils look really rough along with all the wiring so I'm going to have to order some new ones and get to installing those and see what it does.

      long long road ahead of me...
      Had a few GTR's here and there..

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      • #4
        You're welcome. There's 2x plugs on TPS, I think it was one for idle, WOT (Wide Open Throttle) contacts, one for variable voltage (0-5V).

        The coilpacks, sparkplugs are meant to be replaced every 100,000kms on stock engines (same with coilpack loom, ignition module). With modified engines the dwell settings for coilpacks tend to be modified, so the coilpacks don't last 100,000kms.

        Also clean the earths which helps.
        RESPONSE MONSTER

        The most epic signature ever "epic".

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        • #5
          Skym! I'm not sure why I never inquired but who are you and what country are you from? You're like a Sean Morris or something?
          No build thread.
          1991 nissan
          El terror

          "Built not bought" sooner or later = "broken not running"

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          • #6
            Ill try contact cleaner on the TPS and hopefully that will fix it, I understand the contact points bend and it gives the ECU the wrong voltage.

            Car has a new ignition module in it, but coils look ancient so will replace those and see what happens. Didn't order the harnesses but I have a feeling that might be a good idea...
            Had a few GTR's here and there..

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