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unstable idle

Engine/Gearbox questions and discussion
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quarkhimself
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Re: unstable idle

Post by quarkhimself » Thu May 22, 2014 11:49 am

indigolemon wrote: Sorry man, just re-read this all properly. It seems I completely missed the word "don't" :oops:

Apologies for making you waste your time, teach me to post from my phone :?
That's ok. Thank you guys for your help, i'll try to get this sorted between today and tomorrow.
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Post by quarkhimself » Thu May 22, 2014 7:37 pm

today i tried to bleed the air out of the cooling system. this time i did it with the engine running. i thing i did everything right but the idle keeps acting crazy but only when the engine is hot.assuming i bled the air out properly, evidence sugest that it might be the iacv causing this, right ?
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Post by SPYDOR » Thu May 22, 2014 7:55 pm

Is the coolant expansion bottle up to the max level as well? Did you try the radio fuse removal?

As long as you screwed the plunger almost all the way in on the FITV and you have no vacuum leaks around the intake systems then it is very likely the problem is with the IACV so take it apart and give it a really good clean, the filter might be really blocked.

If this doesn't sort it there are 1 or 2 other things you can check, like the TPS for example.
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Post by ADS1 » Thu May 22, 2014 8:26 pm

Check exhaust Manifold, and especially downpipe. I had these exact same symptoms, and found small leak in downpipe near oxygen sensor. Fixed the leak, and problem solved.

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Post by SPYDOR » Thu May 22, 2014 8:34 pm

+1 I had a similar issue with my old motorbike when an end-can which was not sealed tight enough, causing running problems.

I have heard of many people having this problem when fitting a large diameter exhaust system on their car, thus removing all the back pressure when the engine is not tuned to run that way.
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Post by quarkhimself » Thu May 22, 2014 8:53 pm

SPYDOR wrote:Is the coolant expansion bottle up to the max level as well? Did you try the radio fuse removal?

the expansion bottle is up to max. i haven't remove the radio fuse because i don't know wich one it is. i did remove the negative from the battery for a few minutes, hoping it would do the same.
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Post by quarkhimself » Thu May 22, 2014 9:00 pm

ADS1 wrote:Check exhaust Manifold, and especially downpipe. I had these exact same symptoms, and found small leak in downpipe near oxygen sensor. Fixed the leak, and problem solved.
actually when i took the car to the shop to get the clutch changed the guys told me i had a leak in the exhaust.i think he said something about a screw missing in the downpipe or something. i'm going to try clean the iacv tomorrow, if that doesn't work i guess i'll have to take it to the shop to get it sorted. i was planning on taking it to the shop to get the cam belt changed an the exhaust fixed in the next couple of weeks, guess i'll have to o it sooner rather than later.
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Post by SPYDOR » Thu May 22, 2014 9:12 pm

That's promising to hear. Hopefully the downpipe leak is the source of the problem and you'll be back to normal in no time! 8-)
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Post by derrick1988 » Thu May 22, 2014 9:14 pm

SPYDOR wrote:+1 I had a similar issue with my old motorbike when an end-can which was not sealed tight enough, causing running problems.

I have heard of many people having this problem when fitting a large diameter exhaust system on their car, thus removing all the back pressure when the engine is not tuned to run that way.
I completely agree spydor I fitted a cat back system to my a8 with a 4 1/2 backbox and my idle and low end revs are all over the place! and for the record I have no leaks at all just a malfunctionin cat so I imagine with all included that's the issue!

ps how do I go about getting car to run better on a bigger exhaust set up? sorry for the thread jack!!! :oops:

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Post by quarkhimself » Thu May 22, 2014 9:38 pm

SPYDOR wrote:Did you try the radio fuse removal?
is that fuse in the fusebox under the hood, or in the one inside the car ?
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