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Fmic + Idle

moobaque

By moobaque,
in Engines & Forced Induction

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moobaque Rising Star

moobaque

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Hey all,

As many of you prolly know from my other current thread i've just installed a fmic on my r33.

My problem is to with my cars idling. I have done some searching through the forum about the whole need to retune thing and i would have to say the overwhelming majority say that there is no point in a retune if its simply just the fmic upgraded and nothing else (eg. no increase of boost)

So having said that why would my car run rough when it idles straight after start up?

Then if I go for a drive the car performs perfectly fine until u let the revs drop completely (like when u come to stop). The revs just continue to drop beyond the idle point and the car stalls!?

My car would randomly do this maybe once every couple weeks before the install so i just figured my aac valve failed occasionally. but now its non stop the car wont idle after being on higher revs.

So at the end of all this what do people think is wrong.

could it be that during the many days my cars been off the road the aac valve has become stuck closed.

could it be an air leak in the new piping for the fmic (but i would have thought this would cause problems all the way through the rev range like not hitting previous boost levels due to pressure loss)

or potentially does my power fc need some tlc at the tuners?

any help would be much appreciated as i want to be able to drive my car asap. (currently i'm getting around in a early 90's volvo and every time people see me in it a die a little inside ;))

Cheers

Camden

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RBWPN.6 Collaborator

RBWPN.6

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Test it by getting another AFM and seein if it still happens, i replaced mine recently and did the trick, if the change over aFM doesnt do ur car any just , there is a good AAC valve cleaning thread some where on here really handy...

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moobaque Rising Star

moobaque

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Test it by getting another AFM and seein if it still happens, i replaced mine recently and did the trick, if the change over aFM doesnt do ur car any just , there is a good AAC valve cleaning thread some where on here really handy...

Yeah mate i did see that thread about the aac. Thinking i might give that a burl tonight as well as just giving my afm a clean out with some contact cleaner.

Only thing im a bit unsure about is doing the whole idle point reset as im not using the stock ecu anymore (power fc)

Cheers

Camden

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eddieeeee-ro Proficient

eddieeeee-ro

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as in its just dirty or u recon it might need replacing?

is there a method of testing the afm? i don't really want to go out and buy one to find its not the problem.

know anyone that you can borrow from?

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BAMR33 Mentor

BAMR33

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Test each of these one at a time so you know what the culprit is.

1. tighten all clamps again

2. adjust the screw on the IAC valve while the car is idling, see if you can find a smooth idle point.

3. Clean afm

4. Check that no vacuum hoses have removed and not put back on during installation i.e. to charcoal canister.

5. Pressurize the intercooler piping, look for any leaks.

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moobaque Rising Star

moobaque

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Well i attacked the AFM and its connector with some contact cleaner yesterday and it seems to have made a difference. car doesn't stall anymore and in general drives fine but sometimes when coming down in revs it still drops a little low to then bounce back up to where it should idle at.

I've also noticed the car seems to be running quite rich as there is a lot of black splatter all over the arse of my car.

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cheez Mentor

cheez

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on start up does the car still run rough or has this stopped completely? doesnt stall anymore? thats good if its problem fixed.

as for running rich, stick the car on a dyno and get it tuned again. imo a power fc doesnt learn like a standard computer, so a tune will be needed (correct me if im wrong). since it was tuned for a small side mount it only expects so much and now your cooling alot more air in a larger space.

my 2cents

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moobaque Rising Star

moobaque

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on start up does the car still run rough or has this stopped completely? doesnt stall anymore? thats good if its problem fixed.

as for running rich, stick the car on a dyno and get it tuned again. imo a power fc doesnt learn like a standard computer, so a tune will be needed (correct me if im wrong). since it was tuned for a small side mount it only expects so much and now your cooling alot more air in a larger space.

my 2cents

It starts up fine now.. and doesn't stall anymore, sorta. On letting the revs drop back towards idle it still goes to far, the car then kinda stuggles for second and then kick back to the correct idle position.

And yes the Power fc isnt going to protect its self etc like the stock computer. But something is causing the maps to be wrong and its running really friggin rich.. the whole back of my car is getting covered in black shite. Will def be back for a tune when i get free second (DAMN YOU WORK!)

Cheers

Camden

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