Unstable idle. Filthy TB now cleaned

Yiannis197

Yiannis197

Paid Member
No errors, no faults, no flashing dash lights, no misfire. Just unstable idle when the car is up to temperature. Sometimes the revs dip really down and then back up again, however it hasn't even stalled (yet). It seems to be temperamental and when it kind of stabilizes itself it's quite low (lower than normal anyway).

Other than that it drives normal, no issues whatsoever, performance wise the same.

It can't be coilpack surely otherwise I'd be getting misfire errors, it can't be K-tec's induction kit because loads of people use it without reporting a similar issue. Lambda sensor on its way out possibly? Crank sensor? I haven't ever cleaned the throttle body (do they need cleaning anyway??).

Thanks guys.

By the way when the engine is warm it operates like that, it always has been so I never thought it to be an issue.

http://www.youtube.com/watch?v=WM700T80o-Y
 
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Is it mate? But mine is stock, do you reckon it went tits up all of a sudden? Is something like that repairable or I'd have to source another one?
 
1. give the throttle body a clean - does make a difference

2. remove and clean the end of the tdc sensor if 1 doesn't make a difference
 
Mine did something similar the other day. I found the air pipe to the throttle body had come off at the bottom.
 
I had a similar thing with mine but when it was cold. I took the TB off and cleaned it, also took the MAP sensor off the manifold and cleaned that. Has been fine ever since.
 
Cheesy said:
Mine did something similar the other day. I found the air pipe to the throttle body had come off at the bottom.
Click to expand...

BenW said:
I had a similar thing with mine but when it was cold. I took the TB off and cleaned it, also took the MAP sensor off the manifold and cleaned that. Has been fine ever since.
Click to expand...

Cheers guys, that's my job tomorrow.

Ben where is the map sensor located?

EDIT. Just found it, an old post from ralphyBMW
''MAP Sensor - 8200719629
This sits on the top left of the inlet manifold, looking at it from the front, and is tricky to remove. New cost circa £100 @ trade, with VAT @ 17.5%.''
 
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ok guys I took the throttle body off today. Dear lord not only it was filthy but there was loads of oil on the inside of the induction/inlets which must be the condensed oil vapors being funneled back to the engine...hm...oil catch tank next purchase me thinks...

10837502915_fb5f7d7abe_b.jpg
Untitled by YiannisR27, on Flickr
10837844073_271b2fc363_b.jpg
Untitled by YiannisR27, on Flickr
10837574286_751462836b_b.jpg
Untitled by YiannisR27, on Flickr


I gave it a good wash and here is the outcome

10837522285_cafca6e8a8_b.jpg
Untitled by YiannisR27, on Flickr

It seems to be all right now but I'd have to go for a drive to make sure the idle is now settled. If not I'll try to disconnect and clean all the sensors!

Thanks for your help!
 
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That looks pretty clean considering ! Glad it's fixed it, I was amazed something so small could cause such major problems when mine was acting up.
 
Cheers Warren, again I guess it's been fixed. I started up the engine, allowed it to reach temperature and it didn't show any unsettling signs. However I'd have to go for a blast to 100% confirm it's been sorted.
 
yes the one next to RS logo is the MAP one indeed, for some reason i thought that the MAP was the one at the back, apparently I was wrong.
 
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