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TaylorS

Help! R34 gtt manual converted running rough

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Hey everyone. I just got a manual conversion done on my 1998 r34 gtt and now it is running funny. It revs very slow and goes slower then my na r34 now. It is still running the auto ecu. Im thinking that might be the problem? Or maybe the coils? Please anyone that has had this kind of problem let me know.

Ps. Sorry if this is in the wrong part of the forums 

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Auto ECU will not be the problem.  The only difference between auto and manual ECUs (apart from slight differences in mapping) are that the auto ECU also contains the TCU.  Oh, and the idle ignition timing is 20° in autos, not 15° like in manuals.

There could be the usual million explanations.  From coils, to dirty AFM or faulty wiring.  Perhaps you need to do a diagnostic on the ECU and looks for codes.

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1 hour ago, GTSBoy said:

Auto ECU will not be the problem.  The only difference between auto and manual ECUs (apart from slight differences in mapping) are that the auto ECU also contains the TCU.  Oh, and the idle ignition timing is 20° in autos, not 15° like in manuals.

There could be the usual million explanations.  From coils, to dirty AFM or faulty wiring.  Perhaps you need to do a diagnostic on the ECU and looks for codes.

Ok thanks mate i will give the diagnostic tool ago and see what it finds when i get home. The car seemed to run fine before it was converted. If the car was running fine before could it still be the coils? 

Also the car has no aftermarket mods except a hks catback

Edited by TaylorS

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The logical source of problems would be wiring that was f**ked up during the conversion.  The driver's side engine bay loom that services the plugs on the transmission is an example of a place that you need to make changes.

Coils much less likely to die except by pure coincidence.  AFM wiring, oxy sensor, knock sensors are all more likely to be abused during work in the engine bay.

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10 minutes ago, GTSBoy said:

The logical source of problems would be wiring that was f**ked up during the conversion.  The driver's side engine bay loom that services the plugs on the transmission is an example of a place that you need to make changes.

Coils much less likely to die except by pure coincidence.  AFM wiring, oxy sensor, knock sensors are all more likely to be abused during work in the engine bay.

Ok thanks for the tip mate. It wasn't me who did the conversion, i got it done from a shop so i really hope its not the wiring because i wouldn't know what to do then because the shop isnt sure why its like that either.

I will charge the coils anyway and will put some spitfires in. 

I should also add that at random points in the higher rpm it seems to kick in and then drops back out again.

Sorry for all the questions and stuff

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11 minutes ago, Robocop2310 said:

Did you do any other mods with the conversation? If so you may need a retune.

No mate, everything is stock except the catback. Everything else is standard 

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That’s strange. Check your turbo casket, bov and intercooler piping might have fallen out during conversation.

Good luck mate.

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3 minutes ago, Robocop2310 said:

That’s strange. Check your turbo casket, bov and intercooler piping might have fallen out during conversation.

Good luck mate.

Thanks for the tips mate, i will check that out too 

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3 minutes ago, TaylorS said:

Thanks for the tips mate, i will check that out too 

All good mate.

Also as some have suggested plug in a cable and run some diagnostics if possible.

Could also be the exhaust too check piping.

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4 hours ago, TaylorS said:

Ok definitely will try that tomorrow. Do you think it could be a boost leak causing all this?

Yes definitely a possibility but jack the car up and check exhaust piping ang turbo gasket first followed by hoses and blow off valve leakage.

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Couple of times I've had the circlip on the turbo actuator arm fall off and the actuator disconnect. First time it was on a CA18DET and ran absolutely gutless. It's also happened on my RB25DE (with turbo conversion) but wasn't as bad cos the compression is higher so just felt like it was running non-turbo again.

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12 minutes ago, DatsunBanana said:

Couple of times I've had the circlip on the turbo actuator arm fall off and the actuator disconnect. First time it was on a CA18DET and ran absolutely gutless. It's also happened on my RB25DE (with turbo conversion) but wasn't as bad cos the compression is higher so just felt like it was running non-turbo again.

Thank you for that, i will check that out as well. It could be anything at thid point haha. It does run guttless so it could be that

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Update: hey everyone i was playing around with the car and i think i have narrowed the problem down to a turbo issue. it seems like i am getting no boost. the boost gauge reads all the way up the top of the gauge at max and i can hear the turbo spalling  but it feels like im getting none of it?
does anyone know what could be wrong from that kind of an issue? is the bov broken?

thank you

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