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Model specific boards => Golf mk2 => Topic started by: snake16valve on 23 August 2006, 20:28

Title: Rough idle.
Post by: snake16valve on 23 August 2006, 20:28

Hi all.
My latest problem with my car is that when it is ticking over the revs are going up and down like mad.
It will idle at 1100rpm fine then it will drop to as low as 300rpm then up then back down all the time.
Some times the damn thing even cuts out when i come to a junction.
I have checked all the hoses and my inlet manifold to see if it might be drawing in some air.But they all look ok.Also cleaned my idle control valve.
Please help what else can i try ?
My car is a 1991 mk2 golf gti 1.8 16v kr engine code.

Thank's for any help i get ! Also thank's for the use of the forum !

Title: Re: Rough idle.
Post by: Ktuludays on 24 August 2006, 06:23

Check isv. if it buzzes then it is working ok. give it a good clean with carb cleaner or soak in petrol.

also check electrical connections on throttle over run switch. top of throttle body

Title: Re: Rough idle.
Post by: Judderi on 24 August 2006, 08:38

Double check all your hoses. I had this and it was the little pipe under the ISV had come off. Also check the throttle position switch. Make sure its clicking when the throttle is closed.

Title: Re: Rough idle.
Post by: Brads MK2 GTI on 24 August 2006, 09:19

Check the idle switch.

Title: Re: Rough idle.
Post by: snake16valve on 24 August 2006, 13:35

Thank's guys for the help.
I think that my throttle switch is goosed ! It's not even touching anything and also the little micro switch is not clicking...Does this sound like the thing that you are speaking about ?

Thank's again..

Title: Re: Rough idle.
Post by: Gambit on 24 August 2006, 13:40

aye that really needs to be working

you can test it my holding the throttle above 2k rpm & pressing in the micro switch. the revs will drop if its working

Title: Re: Rough idle.
Post by: snake16valve on 24 August 2006, 13:58

Hi again gambit, thank's for that info.
I tried the switch i pressed in the little red button and nothing happened no clicking sound ! I think that the small spring inside the switch has gone.
Where could i get a new one of these from ?
Can anyone help me with a part number for such a thing ?

Cheer's again....

Title: Re: Rough idle.
Post by: Judderi on 25 August 2006, 09:41

I will warn you now, there not cheap! I needed one a few weeks back and there something like 50 or 60 smackers new. I managed to get one from a scrappy for £20.

Part no.

027 133 061 A

Title: Re: Rough idle.
Post by: Veedubgt18v on 25 August 2006, 17:27

mate they have well gone up in price then! i got one a couple years back and they were like 25 quid!!  scrappy job the tbh or a micro switch from maplin or something if your handy and electrics lol

Title: Re: Rough idle.
Post by: snake16valve on 25 August 2006, 17:31

Thank's for the info and the part number.
I think i will be going to the scrapys in the morning....

Cheer's guys !

Title: Re: Rough idle.
Post by: ScottMk2Gti16v on 27 August 2006, 11:39

I've got a similar problem with my 1991 mk2 gti 16v.   Bear with me as I'm not technical with cars.....

But mine does the same thing - it's not really a problem with it revving up and down - it's just when you come up to a junction and put the clutch in the revs drop down to about 300 and it stalls unless you give the accelelator a little flick.   Not sure the name of it - but there's a screw beside the throttle cable under the bonnet - turning it increases/decreases the air flow I believe?   Every other day I have to unscrew it some more as the idle speed keeps dropping - seems the screw is tigheting by itself therefore making the idle speed drop - am I making sense?   Is it just a faulty screw or a faulty part?

Sorry for the vague descriptions....I'm a bit of a newbie to parts and technical knowledge...but learning quick...

Title: Re: Rough idle.
Post by: snake16valve on 27 August 2006, 18:07

Hi Scott, there should be a locking nut on the screw that you are talking about.
Once you have set the screw to a position that it is ticking over fine then all you do is lock it in position with the nut.
It sounds to me that you haven't got the nut on the screw thats why you have to alter it every other day.
It is coming loose with the vibration of the engine.

I hope this helps you a little Scott.

Title: Re: Rough idle.
Post by: ScottMk2Gti16v on 27 August 2006, 21:08

Thanks for that - I'll have a look at it in the morning. I'm pretty sure there isn't a locking nut on it - the screw just goes directly into the hole.

I mentioned in my original post that it's to do with the air flow (I think). Any chance you can confirm to a non-techie the proper name for this part and what it's job is.  i.e. turning it increases air flow into the engine...which does what?   If I had to get a new locking nut what part would I ask for?

Am I right in saying the idle speed should be about 1000rpm?

Cheers for your help,
Scott

Title: Re: Rough idle.
Post by: snake16valve on 27 August 2006, 21:34

Hi again Scott.
I am not much of a brain box either so i cant say what it does. To be honest i think it is summit to do with the engine idle (tick over).As for the nut that you need just get one from any scrap yard.
As for engine idle anything around 900rpm - 1100rpm is OK.

cheers again and good luck m8.

Title: Re: Rough idle.
Post by: Gambit on 28 August 2006, 09:37

the idle screw doenst need a locking nut. you just need to replace the wee rubber O-Ring on the screw - this is what gives it a tight seal

you can get replacement O-Rings at any local motor factors shop for about 50p

also, the reason its stalling approaching junctions etc is because the CO% is not set correctly - there is a guide in the maintenace section.

Title: Re: Rough idle.
Post by: rowlers on 28 August 2006, 10:15

I've also had this prob when i first got my valver about 2 years ago. got the CO set  get 40MG!)spot on, cleaned the isv etc... still done it more so when engine really hot.

I cured the prob with a new hall sender from eurocarparts (about £30) and a new ISV control module off ebay for about a £1! It still does it but only about once a month.

Mine is also running very lean at the moment - about 0.8% CO at last MOT (must be why I 40 MPG :grin: :grin:). but will be set up very shortly when my new head is fitted anyway.

Title: Re: Rough idle.
Post by: ScottMk2Gti16v on 28 August 2006, 10:50

Quote from: Gambit on 28 August 2006, 09:37

the idle screw doenst need a locking nut. you just need to replace the wee rubber O-Ring on the screw - this is what gives it a tight seal

you can get replacement O-Rings at any local motor factors shop for about 50p

also, the reason its stalling approaching junctions etc is because the CO% is not set correctly - there is a guide in the maintenace section.

Thanks for that I've have a look into it.   CO% guide - is this what you're talking about? http://www.golfgtiforum.co.uk/index.php?topic=31611.0

PS - what does CO% mean?

Title: Re: Rough idle.
Post by: Gambit on 28 August 2006, 13:14

its just simply setting the fuel mixture - its how its measured

this is the link you need
http://www.golfgtiforum.co.uk/index.php?topic=22031.0

Title: Re: Rough idle.
Post by: snake16valve on 29 August 2006, 17:31

Hi Gambit.
Can you tell me what breather hose to pull off ?
thank's.


 (after the engine is at temp), pull off the breather hose and block the airbox hole.

Title: Re: Rough idle.
Post by: Gambit on 30 August 2006, 09:47

the black one that is going into the top of the airbox lid - u can see it on your pic running from the airbox underneath the alternator bracket to the front of the engine block

Title: Re: Rough idle.
Post by: snake16valve on 30 August 2006, 18:22

Thanks Gambit. Thats made it easy to find.
It will be getting sorted at the weekend.

Cheers for the help !