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Author Topic: high idle on mk2gti 8v  (Read 1446 times)

Offline lordbigsack

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high idle on mk2gti 8v
« on: 22 February 2011, 16:16 »
since changing the head gasket i have had a few issue with the idle on the car.  first was hunting, fixed with a new ISV.  Now it's idleing higher than it should be 1500rpm after it has warmed up.  From cold the idle is spot on, only after it warms up does it idle higher.  If you disconnect the temp sensor it drops back down to a sensible idle(1k).  Garage is suspecting its a faulty ECU but that sounds a bit mad to me.

any thoughts?

cheers,

Scott
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Offline Benrevs

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Re: high idle on mk2gti 8v
« Reply #1 on: 22 February 2011, 17:11 »
Sounds daft, but have you changed the temp sensor?!
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Offline rob.043

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Re: high idle on mk2gti 8v
« Reply #2 on: 23 February 2011, 09:26 »
its a digifant engine ya?

RJ's tuning guide may be a good place to start, sounds like it may not be set up correctly after its rebuild.

http://www.golfgtiforum.co.uk/index.php?topic=33253.0

I would'nt think its the ECU. Checking for split breather pipes etc would be an idea too
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Offline Wayne

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Re: high idle on mk2gti 8v
« Reply #3 on: 23 February 2011, 09:34 »
Might be worth replacing the temp sender as a 1st step.
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Offline rubjonny

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Re: high idle on mk2gti 8v
« Reply #4 on: 23 February 2011, 10:10 »
check the idle switch is clicking when the throttle is closed, and the wiring to it behind the throttle body hasnt snapped
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Offline lordbigsack

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Re: high idle on mk2gti 8v
« Reply #5 on: 23 February 2011, 11:07 »
collected car last night and they have checked the following, timing, dizzy, fueling, breather pipes, vacuum pipes, wiring, 2xtemp sensor, knock sensor, tested with a sensor simulator, setup the engine and hydrocarbons are down to 60 (he said that was good for engine of this age).  He has had a meter across all the sensors to ensure they are doing what they are supposed to.  He was scratching his head a bit and came up with ECU or possibly a faulty isv.  The ISV was a £50 job from hong kong off ebay, which is setting casting doubt in my mind.  Have already spent a fair whack of cash on this and dont want to jump the wrong way (again)  I am currently in.  Its not hunting at all, the idle just increases as it gets warm until its idling at 1500rpm after about 20 mins of driving.


sensors and wiring have been replaced, so were some of the vacuum pipes.


Which way would you jump - ecu, isv or something else?

ta
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Offline rubjonny

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Re: high idle on mk2gti 8v
« Reply #6 on: 23 February 2011, 11:21 »
did they set it up as per the guide? if not, print the guide out and get them to do it again. trouble is most garages think they can set the digi up like an old carb car, but you cant
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Offline vr6 south

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Re: high idle on mk2gti 8v
« Reply #7 on: 25 February 2011, 10:14 »
Some of the ISV's on Ebay are not all they are supposed to be. I had to return three before I got one which was working correctly! Try testing yours on another car to see if it's working as it should be.
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