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High Idle help please

Posted: Mon Sep 24, 2012 2:12 pm
by bas
I recently cleaned the throttle body but now the engine is idling too high.

It currently idles around 1100-1200RPM whereas it used to sit closer to 700RPM

I have adjusted the idle via the screw on the TB but its at it lowest limit, I have also re-set the ECU.

Re: High Idle help please

Posted: Mon Sep 24, 2012 2:20 pm
by Taz
Did you clean out the stepper motor when you did the throttle body?
If that is screwed I have 2 spare to sell.

Re: High Idle help please

Posted: Mon Sep 24, 2012 3:20 pm
by silverGPX
make sure the accelerator cable isnt adjusted too tight and pulling the butterfly open a tad

Re: High Idle help please

Posted: Mon Sep 24, 2012 3:30 pm
by Taz
silverGPX wrote:make sure the accelerator cable isnt adjusted too tight and pulling the butterfly open a tad
That too, although i assumed he did this when he adjusted his idle - might be jumping the gun though! :cyclopsani:

Re: High Idle help please

Posted: Mon Sep 24, 2012 4:25 pm
by silverGPX
also you could have a vacuum leak

Re: High Idle help please

Posted: Mon Sep 24, 2012 5:04 pm
by bas
silverGPX wrote:make sure the accelerator cable isnt adjusted too tight and pulling the butterfly open a tad
Yes I have made sure the throttle cable was not too tight to open the butterfly valve so not that.
silverGPX wrote:also you could have a vacuum leak
How can you check for a vacuum leak?

I didn't replace TB gasket with brand new one when re-assembling, however the idle seems significantly higher to me than what a leak might cause.

Re: High Idle help please

Posted: Mon Sep 24, 2012 5:11 pm
by bas
TAZ could you elaborate on cleaning the stepper motor.

When I cleaned the TB i removed the stepper motor and wiped it down abit with a cloth but not much else. I cleaned the butterfly bypass air passage though.

Also is it important to clean the area where the coolant flows into the stepper? I did not clean that pasage.

Re: High Idle help please

Posted: Mon Sep 24, 2012 5:20 pm
by Taz
Unless your stepper is pretty much on its way out, what you have done should be enough. It could also be a case of the plunger having too much friction and having trouble opening and closing to let the air flow through.
How long ago since you reset the ecu? leave the car running for 30min or so, you possibly just havent given the ECU enough time to reset yet.

Re: High Idle help please

Posted: Mon Sep 24, 2012 5:38 pm
by bas
I reset it then let it idle for a bit(not 30min though) and have been driving it around since.

My stepper is the old brown backing cover one too btw.

When I was checking it out the plunger was difficult to press in wards and the plastic looked very rough and old.

Re: High Idle help please

Posted: Mon Sep 24, 2012 5:39 pm
by silverGPX
do you have the aircon running considering you reset the battery itll default to 24 deg max fan and ac on

Re: High Idle help please

Posted: Mon Sep 24, 2012 5:40 pm
by silverGPX
do you have the aircon running considering you reset the battery itll default to 24 deg max fan and ac on

Re: High Idle help please

Posted: Mon Sep 24, 2012 5:48 pm
by bas
silverGPX wrote:do you have the aircon running considering you reset the battery itll default to 24 deg max fan and ac on
Nah its still that high with aircon off.

Re: High Idle help please

Posted: Tue Sep 25, 2012 9:55 am
by PHIL069
Did you re-connect the vaccum line on the side of the throttle body, under the Throttle Position Sensor?

Re: High Idle help please

Posted: Tue Sep 25, 2012 10:03 am
by bas
PHIL069 wrote:Did you re-connect the vaccum line on the side of the throttle body, under the Throttle Position Sensor?
I'll have to double check but i was pretty confident i reconneced everything.

Re: High Idle help please

Posted: Tue Sep 25, 2012 6:48 pm
by kiz
bas wrote:
PHIL069 wrote:Did you re-connect the vaccum line on the side of the throttle body, under the Throttle Position Sensor?
I'll have to double check but i was pretty confident i reconneced everything.
:lol: :lol: Yea check vacuum lines :D. Apparantly they can be the cause of idling at 4k revs, who woulda thought

Re: High Idle help please

Posted: Mon Oct 01, 2012 11:11 am
by bas
Ok after having a work car for a couple of days I was back in the FTO over the weekend.

The Revs still seem high but have dropped to around 1000Rpm at idle instead of 1100-1200Rpm.

I checked all the vacuum lines and everything was connected.