Idling?

[BlackGTI-RMatt]

Does anybody have any idea why my car is idling up and down from 1000 to 2500 for the first 20 mins wen you start it up From cold but wen it's warm and you rev it? It does it again then levels itself again?? Weird wonder if anybody can help?

 

[red reading]

It's going into idle over run on the ecu,your base idle is too high go thru the "search function " on the site and look for high idle cures

 

[BlackGTI-RMatt]

But it's Only got a standard ECU?

 

[red reading]

That's what i thought, it is doing as i have said, basically the car is idle is so high it thinks the car is going down a hill and on over run, you need to get the idle down to stop it

 

[BlackGTI-RMatt]

So how do you turn it down then mate cus I did that search you said and it didn't come up with much? Sorry I don't no alot bout these cars yet? Only had few weeks.

 

[PobodY]

I'd start by playing with the idle adjustment screw... I've read that can reduce your idle speed.

Seriously though, this is one of the most common questions... and there's no easy answer.
Do a fault code check.
Check vacuum lines.
Check the BOV.
Check the PCV.
Check the TPS.
Check the throttle stops.
Check the lambda sensor.
Check the engine temperature sensor.
Clean/replace the IAC valve... and so on.

Sometimes the act of fiddling with all the bits fixes the problem, and you never really know what it was.

 

[BlackGTI-RMatt]

Where bouts is the temperature switch located on the engine and why would my temperature gauge not work??

 

[splmum]

Me thinks you better start reading this, all your answers are in there, you just have to find them.

http://www.gtirworkshopmanual.com/default.aspx?v=1

 

[PobodY]

Where bouts is the temperature switch located on the engine and why would my temperature gauge not work??

That's the kicker; the gauge and the ECU sensor are two different parts next to each other in the elbow on the back of the block (just near the oil filter). - The gauges can be reading fine, but the ECU thinks the engine is cold so keeps opening the IAC valve.

I can't remember if it's a diagnostic item or not (i.e. the ECU will tell you when the signal from the sensor is wrong), but it's worth doing a fault code check first to see if it points-out anything; then at least you've got somewhere to start.