Had mycar a couple.months now and loving it, but noticed something. When I start it from cold, itll idle at normal revs for about 10 or 20 secs, then climb to hover about 1k. It idles around this for the first couple of minutesof driving, then returns to normal idle revs.

Is this normal, or a sign of a bigger problem to come.

Will get a video later if it decides to do it.

Exactly the same as me, as i said in my other thread 5 minutes ago im also goin to make a video of it and post it later.

Had a look at your thread and seems exact same, however not had any issues with it not starting. Also doubt mine is throttle sensor as , same as you, blipping throttle makes no difference. Returns to normal after a few mins driving.

Mine also does this. Normally though it will only start to idle higher if I turn loads of stuff on (rear window heater, heated mirrors and headlights etc). If I then tickle the throttle the revs drop back down to normal and it doesn't carry on idling at 1k as you decsribe above.

Phil

Possibly coolant temperature sensor

Funny you should say that as I've suspected the same for a while due to having a little hot-start issue aswell.

Phil

Changed mine for a genuine one and its still the same.

Mine also does this. Normally though it will only start to idle higher if I turn loads of stuff on (rear window heater, heated mirrors and headlights etc). If I then tickle the throttle the revs drop back down to normal and it doesn't carry on idling at 1k as you decsribe above.

Phil

Revs jump up even with everything bar the engine switched on. Revving it doesn't make it stop idling higher.

If it was the coolant sensor, how would I check/know if it was that?

I know for a fact the ECU is programmed to raise idle if below a certain temperature that's why I suggested it, but as already pointed out, it may not be that, just a suggestion. You may be able to prove it by disconnecting the sensor and starting the car, but you'll probably trigger an EML. Alternatively, you could monitor temperatures using VCDS and check for and errors logged.

Edited 26 October, 201213 yr by bondi

I think im going to have to start unplugging sensors and keep re-starting the car each time and seing what affect it has on the car, after spending around £80 on sensors and spending time changing them im no further farward so want to stop playing a guessing game! I had hoped by making this thread people would say "ohh yeah mine did this, it was....." But seems quite rare and not many peoples car's seem to do it....

im out of guesses now! ...apart from maf but not buying a new one!

I bet you have heated Wing mirrors on that is causing this. Lots of owners don't realize putting the setting in the middle activates heated mirrors - In turn raising the idle.

Heated mirrors are off but good guess though! im going to try starting the car and switching fans on full, air-con, heated screen etc all on and see if the idle rises more. Im also going to start the car with a jumper pack on the car with everything switched off and see what affect that has... got to be worth a try?

I will record my startup in the morning.

I will play with the power too

How did you get on with this? My car does exactly the same...

I've gave up trying to fix mine, cant find a solution tbh. No fault codes or anything either..

My Octy does this from cold. Isn't it a cold start device that injects more diesel like a choke on a petrol car?

It's done it since new so I'm not bothered. It never does it when warm.

Thats what i think it is on mine, but... It will do it every turn of the key, making me think the cold start choke is faulty.

Have you checked your battery and alternator output?

Like I say mine seems to do it if I load up the electrical systems.

Phil

Well the weathers been bad recenty so might be worth checking the battery. Will do a drop test tuesday and will check the alternator at the same time.

Yeh I think we will need a new battery at some point.

PAS light on first thing on morning, lights go very dim when turning the wheel and the rising revs when turning electrics on (which I have only known happen recently and not before).

Phil

I've drove about 20 mile or so then parked up for about 2 - 3 hours. When i started the car to my suprise it didnt happen! For the first time in about a month it didnt happen!

I then drove about another 20 mile to a resturant, had my dinner so was away for another hour or so and once again when i started the car the high idle didnt creep in!

I drove about 5 mile or so home, parked on the driveway... Turned it off, waited a minute, started it again and the high idle started again :(

Might help me narrow down the problem more now though!

Not solved, or really looked into this on mine much, and forgot to the video, uni taking over my life.

Only ever seems to do it from a cold start of about overnight. Once it's been ran that day, doesn't do it again, even with a couple hours standing. Pretty sure a new battery was put in by the garage when they were prepping it for sale, but I know this doesn't guarantee it's problem free.

funny how this question has been raised as outside temps have fallen, and all concerned have diesels, including me :think: . Diesels aren't too keen on the cold. The missus' Golf V 140 acts the same when cold. She even gets a coolant warning sometimes on cold days. Had it scanned, told there was no problem. Not replaced the coolant sensor since getting it new in 03 and no other issues. Bar one, but that's a different subject. you, Audi Wichert, Hamburg