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Strange Boosting Issue - R32 Gt-R

niZmO_Man

By niZmO_Man,
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niZmO_Man Grand Master

niZmO_Man

Posted
Posted

Hey guys, I have a rather weird boosting issue with my car.

Car would run/boost fine, then all of a sudden it would run weird and won't boost past 6psi. I shut the engine off for about 5 seconds, fire it up, runs fine, then after a while (5-30 minutes, no certain interval i.e. random), same weird issue.

During this 'boosting problem' mode, as soon as the car goes above 0psi, it will surge and run rich. On overruns/shifting, it will dump fuel (exhaust makes cool popping noises).

Shut engine off for 5 seconds > fire it up > runs fine.

Sometimes it will run fine for over an hour. Sometimes it will happen after 5 minutes.

This issue occurs when the car is warm.

Perhaps AFM(s) is playing up, unable to afford a new pair of them unfortunately. Still doesn't explain why it won't boost past 6psi (or 350mmHg or 'halfway between 0 and 7' according to standard boost gauge).

Any ideas/experience?

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https://www.sau.com.au/forums/topic/408592-strange-boosting-issue-r32-gt-r/
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niZmO_Man Grand Master

niZmO_Man

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  • Author
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Yeah hesitates. Can't hear anything else though.

With the vac leak, why does the issue always disappear if I shut the engine down and fire it up after 5-10 seconds? That thing stumps me. Friken car, just more problems (HICAS flicker issue still there as well, definitely electrical).

I'll have to pull the crap off to fix exhaust leak anyway (not related as issue was present before the leak... I think).

R34_Wong Mentor

R34_Wong

Posted
Posted

Does sound the the AFM's then unfortunately... there are some tuners who can patch them up... I know the guys at RE Customs down here did for me and haven't had an issue since...

Worth taking a look maybe?

GTR_NUTZ Collaborator

GTR_NUTZ

Posted
Posted

I'd say it's your afm's. Try driving over pot holes and if it happens everytime you hit a pot hole then it's most likely dry solder joints on the pins in your afm's. Easy fix.

My car was doing it for a while. Took it to 3 different places and they couldn't find the fault.

iwanta34gtr Grand Master

iwanta34gtr

Posted
Posted (edited)

Sounds electrical / AFM.

Start by cleaning them, grab some CRC mass air flow cleaner from super cheap. Check and clean your connections as well.

If no luck, then go down the repair / replace path.

Just thinking, depending where you are located, maybe there's someone nice on here that can lend you some AFM's to test before purchasing?

Edited by iwanta34gtr
niZmO_Man Grand Master

niZmO_Man

Posted
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Posted

Ooops forgot to follow this topic. Thanks for the offer BWRGTR, I might have to take it up.

I got a pair of AFMs from Brisbane (apparently they were R33 but has R32 written on them lol). Chucked them in this time last week, car ran awesomely. The frequency of the slight miss on idle was reduced, car ran smoothly and boosted to 12psi without issues.

This morning, the problem reared its ugly head again! WTH!? Although the performance degredation wasn't as bad as before, it wasn't going past the 3/4 boost mark (~350mmHg) and hesitating/being lethargic. Shut the engine down at a set of traffic lights, fired it up and it ran good again.

At least on my R31, I just wiggle the AFM plug a bit and it runs good lol. This car brings much electrical headaches.

I'll have to look into doing a solder fix on possibly this or my old pair of AFMs and seeing how they go... Unless someone has a good pair of known fully working AFMs (BWRGTR?) hahaha.

Cheers guys.

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