# Uneven/high idle AFTER cleaning throttle body



## Jory (Apr 29, 2005)

*DISCLAIMER:* I have been putzing with the jetta for the past while and should've been in bed a long time ago. I am therefore not responsible for any grammatical errors or nonsensical babble in the following post.

I just finished a very thorough cleaning on the throttle body and MAF of my '96 (OBDII) 2.0. 
I did not, however, port or physically alter the throttle body itself.
When I started the car, it idled high (around 2500 rpm) and then changed to a dipping/inconsistent idle. 
I took the car for a good 5 minute drive and the idle didn't seem to change. 
I shut the car off for 5 minutes, but it still idled abnormally when I started it again.

Now, when I come to an idle, it dips for a second or two, then idles around 1400 rpm.
Does the ECU just need more time to adjust to the newly cleaned throttle body (it was quite dirty before cleaning), or is it necessary to re-calibrate the throttle body with VAG-COM? I didn't think that was necessary/possible on OBDII Mk3s, but I could be wrong.
On the bright side, the car definitely seems to run smoother








Thanks for any help


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## x3n0x (Aug 31, 2009)

*Re: Uneven/high idle AFTER cleaning throttle body (Jory)*

You probably need to have a TB adaptation done. Even if it is DBC, some have a little electronic idle control valve that has to be adapted.


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## cwcabrio (Dec 16, 2009)

*Re: Uneven/high idle AFTER cleaning throttle body (Jory)*

Try adjusting the idle screw on the tb (If it has one), if that don't work you'll need to set the timing again, probably adjusted with a dirty tb last time.
Good luck. Keep posting.


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## Jory (Apr 29, 2005)

*Re: Uneven/high idle AFTER cleaning throttle body (x3n0x)*


_Quote, originally posted by *x3n0x* »_You probably need to have a TB adaptation done. Even if it is DBC, some have a little electronic idle control valve that has to be adapted.

Interesting. I'll have to look into that.
There's no idle adjustment screw.
I've never heard of anyone else having a similar problem. It seems like there must be something obvious I'm missing


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## Jay-Bee (Sep 22, 2007)

*FV-QR*

You could try leaving the battery unhooked for 15 mins and reconnect and then turn the key forward for 2-3 minutes, you should hear the TB cycle, it is not a real throttle body alignment, but it's a mini calibration.
Vag-com is gonna be the best route.


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## Jory (Apr 29, 2005)

*Re: FV-QR (Jay-Bee)*


_Quote, originally posted by *Jay-Bee* »_You could try leaving the battery unhooked for 15 mins and reconnect and then turn the key forward for 2-3 minutes, you should hear the TB cycle, it is not a real throttle body alignment, but it's a mini calibration.
Vag-com is gonna be the best route.

I'll give it a go. Thanks http://****************.com/smile/emthup.gif


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## Jory (Apr 29, 2005)

*Re: FV-QR (Jory)*

Well, tried the manual reset this evening and it didn't change. I'm gonna give vag com a go this saturday, but I suspect it may not fix it.
I'm kinda wondering if perhaps the throttle body gasket isn't sealing completely...


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## effdbmx1 (Dec 27, 2007)

*Re: FV-QR (Jory)*

I had the same exact problem. Not with a VW but it might help you. My idle was also very messed up after cleaning and people said just disconnect the battery and touch the clamps together(not attached to the battery) and then get in and drive for a couple miles and the computer should reset and act normally. I did it and it worked but not after a couple but more like 20 miles. Try it out maybe it will help


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## cwcabrio (Dec 16, 2009)

*Re: FV-QR (effdbmx1)*

Vacuum leak?


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## Jory (Apr 29, 2005)

*Re: FV-QR (cwcabrio)*

Just tried to reset it with Vag-Com and it didn't do a thing. I've got a new throttle body gasket to throw in there, but it doesn't seem to be leaking (sprayed it with gum cutter).
I'm out of ideas








Might try another t-body


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## Jory (Apr 29, 2005)

*Re: FV-QR (Jory)*

Any other ideas before I fork up the cash for another throttle body?


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## ognjen28 (Jul 8, 2009)

*Re: Uneven/high idle AFTER cleaning throttle body (Jory)*

maybe a MAF? What did you use to clean it? I had a same issue and it turned out it was a MAF. Just a food for a thought


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## Jory (Apr 29, 2005)

*Re: Uneven/high idle AFTER cleaning throttle body (ognjen28)*


_Quote, originally posted by *ognjen28* »_maybe a MAF? What did you use to clean it? I had a same issue and it turned out it was a MAF. Just a food for a thought

I used CRC MAF cleaner. I came across a spare maf in my parts stockpile so I threw it in to see if anything changed. 
No difference


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## cwcabrio (Dec 16, 2009)

*Re: Uneven/high idle AFTER cleaning throttle body (Jory)*

Have you checked that the throttle cable allow the tb valve to reach the rest position and the fully open position?
Have you checked the vacuum hose that conects to the tb for cracks or other leaks?
Does the tb valve moves freely?
Is the timing correct at the crank, cam and distributor?


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## Letizio (Nov 2, 2009)

*Re: Uneven/high idle AFTER cleaning throttle body (cwcabrio)*

i have 98 passat aeb same problem. new o2 sensor on front, cleaned maf -- is pushing about 120 grams on redline 3rd gear . brand new siemens vdo throttle body new plugs new timing belt new valve cover gasket new coolant temp sensor.. wont idle right. have vag com will adapt over and over again with no results. am also getting an p1136 lean add but i cant find a leak anywhere. car has had code for over a year idle has only been messed up since july. even though i can align tb myself do i need to have the ecu matched by any chance?


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## Robert Roberts (Jan 30, 2009)

*Re: Uneven/high idle AFTER cleaning throttle body (Letizio)*

OBD1 MK3 TB have a separate Throttle position indicator do they not?


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## Jory (Apr 29, 2005)

*Re: Uneven/high idle AFTER cleaning throttle body (Robert Roberts)*


_Quote, originally posted by *cwcabrio* »_Have you checked that the throttle cable allow the tb valve to reach the rest position and the fully open position?
Have you checked the vacuum hose that conects to the tb for cracks or other leaks?
Does the tb valve moves freely?
Is the timing correct at the crank, cam and distributor?

Timing is good, butterfly valve is free, I'll check on the opening/closing today.
I'm looking around for another TB to swap in.

_Quote, originally posted by *Robert Roberts* »_OBD1 MK3 TB have a separate Throttle position indicator do they not?

OBDI doesn't have a tps. They use an idle air control valve.


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## Robert Roberts (Jan 30, 2009)

*Re: Uneven/high idle AFTER cleaning throttle body (Jory)*


_Quote, originally posted by *Jory* »_
OBDI doesn't have a tps. They use an idle air control valve.

You sure about that?!
Page 24a- 16 of my MK3 Bentley clearly show a TPS bolted to the side of the TB. This is in the Fuel injection section for OBD1 2.0 cars. NOT OBD2.


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## PBWB (Sep 12, 2004)

*Re: Uneven/high idle AFTER cleaning throttle body (Robert Roberts)*

If it's obd2, you don't need a vag to align the TB....Just turn the key on without pushing any pedals. Wait for the TB noise to go away (~30 seconds) and then fire it up.


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