Mk 3 Golf fast idle...

Mk 3 Golf fast idle...

Author
Discussion

flooritforever

Original Poster:

861 posts

248 months

Tuesday 20th June 2006
quotequote all
Hi all, a little advice if you please!

I have a 1992 VW Golf Mk3 1.8 8v (90bhp). Just lately, I have noticed it seems to be idling fast. Generally between 1000 - 1200 rpm, even when the engine is fully warmed up. I'm not entirely sure how fast this engine should idle, but it can't be much more than 800 - 900 rpm.

Could somebody tell me what the idle speed actually should be? And how I might go about finding whats wrong? It's a pretty simple engine, so i'm hoping it'll be simple to fix!

flooritforever

Original Poster:

861 posts

248 months

Thursday 22nd June 2006
quotequote all
Bump.

Is there nobody that can help????

Fatboy

8,055 posts

277 months

Thursday 22nd June 2006
quotequote all
It could be the waxstat that controls the cold start idle - if that's got rooted ISTR it'll cause a fast regular idle...

flooritforever

Original Poster:

861 posts

248 months

Thursday 22nd June 2006
quotequote all
Fatboy said:
It could be the waxstat that controls the cold start idle - if that's got rooted ISTR it'll cause a fast regular idle...


If "some kinda thermostat for the cold start"'s got rooted what?


Fatboy

8,055 posts

277 months

Thursday 22nd June 2006
quotequote all
The waxstat is a wax filled device that, as it warms up and the wax melts, turns on and off the autochoke - can't remember exactly how it works, but see here for some more information:

FAQ on club GTI

ISTR = I Seem to Recall

If the waxstat is rooted, it'll cause the autochoke to stay on, hence fast idle.

flooritforever

Original Poster:

861 posts

248 months

Thursday 22nd June 2006
quotequote all
Ahhhhhh now I understand! Thank you!

Although, on reading that link that seems to apply to carbed engines. My engine AFAIK has single point injection. Would this make any difference?




Edited by flooritforever on Thursday 22 June 17:14

Fatboy

8,055 posts

277 months

Friday 23rd June 2006
quotequote all
I thought the 90 bhp 1.8 was carbed? It was in the 1992 MK2 I used to have...

flooritforever

Original Poster:

861 posts

248 months

Friday 23rd June 2006
quotequote all
Nope, it's definitely SPI.

They probably switched it from carbs to SPI when they bought it out in the mk3.

quoman

18 posts

219 months

Monday 26th June 2006
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if its ecu related i can help!
www.ecuclinic.com

flooritforever

Original Poster:

861 posts

248 months

Monday 26th June 2006
quotequote all
quoman said:
if its ecu related i can help!
www.ecuclinic.com


Thats the problem, i'm trying to find out what might actually be causing it! With very little success so far it must be said.

I doubt it is ECU related though, given the primitive nature of the injection system.

Edited by flooritforever on Monday 26th June 22:13

quoman

18 posts

219 months

Tuesday 27th June 2006
quotequote all
has the gearbox been out recently? the main trouble with those is mechanics cant be arsed to put the earth strap back on the engine so the ecu got spiked worth checking all earthing points
www.ecuclinic.com

flooritforever

Original Poster:

861 posts

248 months

Tuesday 27th June 2006
quotequote all
No, the gearbox has not been out since I got the car, and it was idling normally then.

lotisi

219 posts

220 months

Thursday 29th June 2006
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Check the rubber mount under the fuel injection body, these crack and cause an airleak which can cause this.

flooritforever

Original Poster:

861 posts

248 months

Friday 30th June 2006
quotequote all
lotisi said:
Check the rubber mount under the fuel injection body, these crack and cause an airleak which can cause this.


Ta! Now we're getting somewhere!

countdedown

1 posts

218 months

Monday 3rd July 2006
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I've a similar problem - feels like dirty jets, if it were on old-fashioned carburettor.
I'm told it's the throttle positioning control - it's a wee black box on the side of the throttle body. Looks like a complete replacement £116.00 + vat from my local VAG dealer.
ANYONE HAVE ANY OTHER IDEAS ON REPLACEMENT/REPAIR

lotisi

219 posts

220 months

Monday 3rd July 2006
quotequote all
countdedown said:
I've a similar problem - feels like dirty jets, if it were on old-fashioned carburettor.
I'm told it's the throttle positioning control - it's a wee black box on the side of the throttle body. Looks like a complete replacement £116.00 + vat from my local VAG dealer.
ANYONE HAVE ANY OTHER IDEAS ON REPLACEMENT/REPAIR


What year is it? Engine code would help too. If you have a connection (behind one of the swith blanks on the centre console or under the gearelver boot) get the fault code memory read by someone with either VAG com or VAG 1552 should cost £40ish and they probably will reset it too.

flooritforever

Original Poster:

861 posts

248 months

Thursday 20th July 2006
quotequote all
Bump!

Update: Local VW and Audi specialist has had a look at the car today. They reckon it's the temperature sender at fault. It appears to be reporting the engine temperature about 20 degrees C lower than it actually is. The net effect of this is that the engine is always being fueled like it is cold, hence the fast idle and the disgustingly low fuel economy I have also noticed.

They can't be 100% sure just yet because the ECU is too primitive to give them a full fault report, so keep your fingers crossed for me guys! I'll find out whether they are right tommorow!

flooritforever

Original Poster:

861 posts

248 months

Friday 21st July 2006
quotequote all
It's fixed!!!!

Now maybe I can stop driving around with half an eye on the fuel gauge. Bloody good job too, as I'm off to London tommorow for the Motorshow. I shudder to think how much that would have cost me in fuel if the car had still be running badly!

jonnydiscopants

125 posts

240 months

Tuesday 25th July 2006
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doh didnt see this!!! I was going to say sounds like temp sensor or simlar... to little to late