My 306 revving really high when starting cold

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pugnz
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Joined: 17 Jun 2009, 11:22
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My 306 revving really high when starting cold

Post by pugnz »

Hi all,

I have just purchased a 1998 Peugeot 306 1.8L manual on Sunday and I totally love the car. Stylish, zippy and easy to drive , I cannot ask for anything more!

However........... the car has a little flaw, where the previous owner failed to tell me about.

When I start the car up on a coldish morning (approx 5-9 degrees) I was pretty shocked to see the engine revving up and then idle at 3000 rpm for 20-30 seconds before dropping down to 2500 rpm and then up to 3000 rpm again for a couple of times before it finally idles at around 1500 rpm.

Once its at 1500 rpm it idles and drives fine without any problems at all.

It is only at the initial cold start up phase where the idle is worryingly high as if the car is going to explode on me while I am in the car..

I didn't get any engine stop lights coming on either.

Did anyone have a similar issue?
Can someone please shed some light on the matter, I am not very clued up about Peugeots therefore any help would be great.

Thanks in advance
citronut
Posts: 10937
Joined: 29 Apr 2005, 00:46
Location: United Kingdom east sussex
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x 92

Post by citronut »

the first thing to look at is the idle speed stepper motor, just to prove it is at fault remove it and clean with carb cleaner and re/fit,

if this seems to fix it you will be best to buy a new one, as they are very delicate and they usualy die not long after blasting them out with carb cleaner,

regards malcolm
pugnz
Posts: 4
Joined: 17 Jun 2009, 11:22
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Post by pugnz »

hi critonut thanks for the tip, i will get onto it this weekend.

i've located the idle stepper motor today and i have read some other posts on removing it from the throttle body, but how do i clean the inside? must i first strip it apart and then clean it with a tooth brush or cloth?

any pitfalls i should be aware of before i strip it apart?

Thanks :)
citronut
Posts: 10937
Joined: 29 Apr 2005, 00:46
Location: United Kingdom east sussex
My Cars:
x 92

Post by citronut »

ok but no you cant steip it down as its a sealed unit, it is a very sensative/fragile device

carb cleaner is an airasol of a solvent used for cleanning dirt and carbon from in and around carburettors, please dont get high on it TEA HE,

all you do is blast it up inside the stepper motor tip (a good blastting)

then bung it back in place and try the car,

it will almost certainly evetually kill the S/M,

this will almost certainly kill the S/M within a week or two, but it will prove if its that at fault if the car runs fine between times

regaeds malcolm
pugnz
Posts: 4
Joined: 17 Jun 2009, 11:22
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Post by pugnz »

well i got my can of carb cleaner today and proceeded to locate the stepper motor without and problems...

however i had some troubles getting to the screws of the stepper motor, so i must detach the hoses connecting to the stepper motor, but how do I do that? do i just yank them out?

also i found something really weird on of the stepper motor. i noticed on the stepper motor plug there were 4 additional pieces of wire soldered onto each of the 4 wires and ends up nowhere? what the hell is that? that is surely not normal??

any advice is appreciated :(
citronut
Posts: 10937
Joined: 29 Apr 2005, 00:46
Location: United Kingdom east sussex
My Cars:
x 92

Post by citronut »

err not sure what they are unless someone has attatched them for test purposes,
i would just make sure they are not touching anything or each other then ignore them for now

and yes i think you can just wiggle and pull out the pipes

regards malcolm
pugnz
Posts: 4
Joined: 17 Jun 2009, 11:22
Location:
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Post by pugnz »

thank for all your help.

a friend of a friend is wrecking a GTI-6, is the coolant temp sensor and stepper motor inter-changable with my 1.8L 16v engine?

Thanks :)
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