Hi everyone.

Can anyone tell me what controls the cold start tickover on my 1999 Impreza Turbo wagon?
When I first start it goes as high as 2500rpm for about the first mile then slowly settles down.
Even when warm it always ticks over at about 1200 for about 15secs before settling down to 700-800ish.
The only control I can find is the throttle sensor but that seems to affect pickup when accelerating if I mess with it too much.
Any clues?

Cheers,

Russ.

 

I have a my99 uk turbo and cold idle is 1500rpm...... warm start idle goes to 1200 rpm then drops to 900 ish rpm normal idle after 2-3 seconds. Your idle does sound a little high.


dip the clutch for a junction and it hangs around 1050 1100 rpm for a second i assume to prevent stall etc but it bugs the hell out of me.



Dean.

 

Tick-over does seem high, my old my00 was about 1600 then 7-800 when warm. No more help to offer you unfortunately, but might be worth asking about at next service as a minimum.
dnc

 

YOu've got the coolant temperature sensor that tells the ECU what temp range you're in and thus the ECU adjusts fuelling and idle to keep the engine running, which results in a high idle from a cold start. It controls the idle directly via the idle air control valve which bypasses air round the throttle plate. There are two screws which can be loosened on top of it so you can twist the IACV one way or the other to alter idle speed, worth a try if nothing else works. Also worth checking that your coolant temp sensor is OK.

 

Cheers for that, any chance of a picture or a link to a one, just not sure where the IACV you are talking about is located?

Cheers,

Russ.

 

If you look down at your throttle body, it's to the right (nearside) of that. It'll have an electrical plug in the top and an air hose in the side, probably around an inch diameter. That should track back eventually to the inlet pipe. It will also have a couple of small bore water pipes in the bottom.

 

Thanks again. I can't see this on my car. It is the later engine, a 99 with the offset coil pack. Would this model be different?

Cheers,

Russ.