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Discussion Starter · #1 ·
Hey guys,

My car is driving me nuts! R32 GTR. Ignition is cutting out/misfiring (more cutting out) randomly. The car is modified a fair bit (not super crazy though) and has an FCON V PRO fitted.

Things I have done to attempt to resolve the issue:

Changed plugs
Swapped Ignitors (tried 3 different ones)
Re did the ground/earth on the Ignitor
New Coils (Splitfires)
Checked for Vacuum leaks

WHat the hell else can I do? Its driving me nuts! My car has been out of commission for 3 months now. It went from being a 550hp beast putting a smile on my face to me wanting to dismantle it and break it!
 

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hi mate, has to be related to the air measurement that the Fcon is getting its signals from. have you tried a new map sensor/ the connections to the map sensor? sounds very much like a loose connection (therefore something simple). did it gradually get worse, or all of a sudden arise?
 

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Is the ignition cut due to a voltage drop/loss I wonder? If so it could be a loom or general earthing problem. Japanese cars tend not to have great wiring.

Have you tied switching off various aftermarket parts and seeing if that fixes it? What else is happening at the same time? Check all the instruments etc. Bypass the ignition switch for a while and see if that cures it. If not, just keep trying.......
 

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oops.. nm
 

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Discussion Starter · #7 ·
Is the ignition cut due to a voltage drop/loss I wonder? If so it could be a loom or general earthing problem. Japanese cars tend not to have great wiring.

Have you tied switching off various aftermarket parts and seeing if that fixes it? What else is happening at the same time? Check all the instruments etc. Bypass the ignition switch for a while and see if that cures it. If not, just keep trying.......
How would I go about bypassing the ignition switch? You mean the ignitor?
 

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Check the connections to the injectors aswell. Wouldn't cause "cutting out", but often when injectors are swapped the metal clips break or go missing, leading to a not so secure injector plug.
 

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does it only happen when hot? I've found the ignition system does not like hot underhood temps.
 

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Have you tried replacing the ignition module? I also had a very similar problem and what happened to me was i got water on the battery and didn't know. It then shorted out and melted one of the wires ( not greatly visiable ). I would follow the wires back from the ignition module and make sure there all good.
 

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Have you tried turning of or disconnecting things like turbo timers or boost controllers? It could be they're causing a problem.
 

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Discussion Starter · #13 ·
Well swapped the CAS wasn't that. Tried regrounding and swapping ignitors again, not that. Have disconnected turbo timer & boost control with no difference. I'm not quite sure as to what else I can do now.
 

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I'll bet there's some kind of wiring problem - maybe replacing the injector loom? Or, you've done the splitfires and ignitor so you're good up to that point, but then maybe the issue is in the wire loom that plugs into the other side of the ignitor (the six prong one), and where that goes (dunno - does that go to the ECU directly?)....anyways, could be a bad wire there.
 

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Discussion Starter · #17 ·
I'll bet there's some kind of wiring problem - maybe replacing the injector loom? Or, you've done the splitfires and ignitor so you're good up to that point, but then maybe the issue is in the wire loom that plugs into the other side of the ignitor (the six prong one), and where that goes (dunno - does that go to the ECU directly?)....anyways, could be a bad wire there.
Looked over it briefly but havent seen anything, just dont know how the wire could just go bad in the middle of a drive though when Idling (thats when the problem started). Im gonna take another look at it
 

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you can try to see if it's a particular cylinder that's not firing, by pulling the injector wires one at a time, and see which one doesn't do anything (pulling the other good ones will make the rough idle worse). So at that point, you can look at either the wiring going to that injector, the injector itself, or even if the coilpacks are fresh and new, maybe the wire going to the coilback has gone bad - things get hot under the hood!

You might also try looking at your O2 sensors - apparently, unplugging one at idle should make things much worse, but if it doesn't change a thing plugging and unplugging the sensor in, then the O2 sensor is definitely bad. I'm going to try that on my GTS-T tonight after work, same sort of misfire problem and I'm guessing it's the O2 sensor on the downpipe. If not....then more of a wild goose hunt :p
 

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me too - misfiring issues seem to be common, and I think I can add one more cause from my recent experience - misrouted vacuum hoses to and from the charcoal canister.
 
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