80q 1.8 poor running

5-E · 04-11-09, 12:22 PM

Hello everyone.

I have recently bought a pearl white 1989 80q which has been pampered all it's life

It is great to drive apart from a small problem with it's starting and running.

Symptoms: Sometimes (but not always) it is reluctant to start and needs a wide open throttle to get it to splutter into life. It sometimes idles at 800rpm, sometimes at 1200 and it hesitates to respond to the throttle on the first choke (once the second choke is open it seems fine).

I've had it looked at by a very well-respected mobile tuning expert who went through everything very thoroughly, said "there are too many right answers here", relieved me of £60 and made no difference whatsoever. It has also had attention from two other local garages but it's still the same.

It has had new air filter, spark plugs, leads, caps and distributor cap.

Any ideas?

PS - it's the 1781cc K-Jetronic model.

BW2309 · 04-11-09, 01:46 PM

Few things to check - first is have the K-Jet system checked to make sure no one's been messing with the mixture.
Make sure the Idle Stabilisation Valve is not jammed, fouled up or just plain knackered!
One more thing is if all these are correct there is a non retrun valve in the fuel pump that if it fails can give starting issues but not likely to cause inconsistant idle.

It won't be much, bound to just need setting up!

BIGGYIN · 04-11-09, 08:40 PM

How would you clean out a control valve for idling stabilization?(or check?}
Just checked on Vag.com,282 Euro,s new.

(KV engine)
Sometimes mine,won,t idle from start.Intermitent fault?Idle somestimes fluctulates between 850 and 1100.
I,ll check the rest that you advised.
How much would it cost,to be checked over and set up?
Thanks,Karl.

vag80 · 04-11-09, 08:53 PM

also check the cold start injector by the throttle body make sure you get a good spray and check the wiring also check the micro switch on the throttle body again wiring and it clicks when throttle is closed

msh · 05-11-09, 01:23 AM

Quote:

Originally Posted by BIGGYIN

How would you clean out a control valve for idling stabilization?(or check?}
Just checked on Vag.com,282 Euro,s new.

(KV engine)
Sometimes mine,won,t idle from start.Intermitent fault?Idle somestimes fluctulates between 850 and 1100.
I,ll check the rest that you advised.
How much would it cost,to be checked over and set up?
Thanks,Karl.

Take it out, apply voltage and watch how sharply moves moving part which restricts air flow. At least it can be done with ISV's used with B3's KE-jet engines, I haven't seen KV ISV yet, maybe it has different principle and movement can't be seen with eye

ISV is controlled by control unit which itself can be faulty, also temp sender, which is used by that control unit can be faulty as well. Or just weak connection somewhere.

BIGGYIN · 05-11-09, 07:19 AM

Thanks mate,i,ll look into it.

5-E · 05-11-09, 12:34 PM

Idle speed stabiliser is one of the chief suspects but disconnecting it doesn't seem to make much difference

The cold start injector was checked as part of the tune up and seemed to be fine.

I forgot to mention that the exhaust doesn't smell right somehow (the tuning man agreed but the emissions checked out fine).

I've been monitoring fuel consumption as well - it does 30-33mpg on short trips to work but did 40mpg on a recent 400 mile round trip to Stansted, cruising at around 70mph. These figures don't seem far from what I'd expect so there cant be that much wrong wi it!

04-11-09, 08:40 PM	#3
BIGGYIN 4 ring whore! Classic Audi Club Member Join Date: Mar 2009 Location: Merseyside Posts: 7,976	How would you clean out a control valve for idling stabilization?(or check?} Just checked on Vag.com,282 Euro,s new.(KV engine) Sometimes mine,won,t idle from start.Intermitent fault?Idle somestimes fluctulates between 850 and 1100. I,ll check the rest that you advised. How much would it cost,to be checked over and set up? Thanks,Karl.

04-11-09, 08:53 PM	#4
vag80 Senior Member Classic Audi Club Member Join Date: Oct 2008 Location: Bracknell Posts: 1,967	also check the cold start injector by the throttle body make sure you get a good spray and check the wiring also check the micro switch on the throttle body again wiring and it clicks when throttle is closed __________________ nothing like a bit of deep dish 200k club member 87-b3 80 83-4000 2 door

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04-11-09, 01:46 PM	#2
BW2309 Banned Join Date: Sep 2008 Location: Derby Posts: 1,245	Few things to check - first is have the K-Jet system checked to make sure no one's been messing with the mixture. Make sure the Idle Stabilisation Valve is not jammed, fouled up or just plain knackered! One more thing is if all these are correct there is a non retrun valve in the fuel pump that if it fails can give starting issues but not likely to cause inconsistant idle. It won't be much, bound to just need setting up!

05-11-09, 07:19 AM	#6
BIGGYIN 4 ring whore! Classic Audi Club Member Join Date: Mar 2009 Location: Merseyside Posts: 7,976	Thanks mate,i,ll look into it.

05-11-09, 12:34 PM	#7
5-E Grown up member Join Date: Oct 2009 Location: Lancashire Posts: 50	Idle speed stabiliser is one of the chief suspects but disconnecting it doesn't seem to make much difference The cold start injector was checked as part of the tune up and seemed to be fine. I forgot to mention that the exhaust doesn't smell right somehow (the tuning man agreed but the emissions checked out fine). I've been monitoring fuel consumption as well - it does 30-33mpg on short trips to work but did 40mpg on a recent 400 mile round trip to Stansted, cruising at around 70mph. These figures don't seem far from what I'd expect so there cant be that much wrong wi it!