Poor running KV

audicoupeparts · 03-11-15, 04:23 PM

KV in a b3 90 quattro
Bought as a project.
Had poor idle.
Changed ISV rubber pipe for a hole free one.
Idles fine now.
New dizzy cap and rotor arm
New plugs
Small vac pipes replaced.
Starts and revs fine for about a minute
Then gradually starts to spit its dummy and starts missing when revved
Won't then Rev over 4k, then gradually gets worse and won't Rev at all and cuts out.
Any ideas folks?
Been a long time since I've messed with a KV so running out of ideas.

Jake Blight · 03-11-15, 04:39 PM

Have you read this thread? It may be of use. Good luck sorting it out.

http://www.classic-audi.co.uk/forum/...ad.php?t=24516

slacky · 03-11-15, 04:39 PM

some pointers here Dave
http://www.classic-audi.co.uk/forum/...t=24419&page=2

audicoupeparts · 03-11-15, 06:00 PM

Thanks for the links guys
I did think fuel related as ok at idle
Will do the tank WUR and metering head filters
Any where available where I can buy new filter for WUR ?

audicoupeparts · 04-11-15, 08:57 PM

Bump
Any ideas?
Also been told about ignition module
On type 85 anyway was under driver side dash on Ali plate
Is there one on b3? Behind kick panel maybe
Need to get this running right for the MOT

Kenquattro · 04-11-15, 09:05 PM

Quote:

Originally Posted by audicoupeparts

KV in a b3 90 quattro
Bought as a project.
Had poor idle.
Changed ISV rubber pipe for a hole free one.
Idles fine now.
New dizzy cap and rotor arm
New plugs
Small vac pipes replaced.
Starts and revs fine for about a minute
Then gradually starts to spit its dummy and starts missing when revved
Won't then Rev over 4k, then gradually gets worse and won't Rev at all and cuts out.
Any ideas folks?
Been a long time since I've messed with a KV so running out of ideas.

Sounds very similar to how my B3 KV 90q was when I bought it. Also, mine wouldn't start when hot, although fine when cold. Mine turned out to have a goosed dizzy. A replacement dizzy cured it.

audicoupeparts · 04-11-15, 09:41 PM

Starts fine
Issues develop once been run for a few minutes
Gradually refusing to rev until cuts
But restarts and idles fine
Really want it MOT d for autumn Sunday morning blasts before it has to be sold on

sam · 05-11-15, 08:11 PM

fuel pump/filter?

quattrostyle · 05-11-15, 08:28 PM

It's your K-Jet, most likely the 'piston' that moves up and down and is operated by the round flap.
Remove the metering head from the top of the airbox, turn it upside down, then you see 2 bend pieces of metal, open them up and take the piston out, don't loose the spring that's behind it! Clean it up and polish it and put it back in.

However now I come to think of it, try to adjust the CO first though the small pipe on the metering head. This helped on my 90q the last time I had this issue. The screw can be turned with a small hex key?
Anyway, start the car and keep it running by operating the throttle, give the CO screw a half turn or less left or right and see if it helps.

dgacampbell · 05-11-15, 08:31 PM

Check if yours has an o2 sensor?

Do the exhaust fumes smell very rich when it starts to die off?

I had a problem with my car at the start of the year, same sort of symtoms, turned out to be a faulty o2 sensor, for whatever reason it was telling the car it was running lean and richened the mixture until it wouldn't run.

just a thought.

03-11-15, 04:39 PM	#3
slacky 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: wirral Posts: 4,452	some pointers here Dave http://www.classic-audi.co.uk/forum/...t=24419&page=2 __________________ *90q-Cab.2.3E-Ur-S6-b2-80 Sport* Member 111

03-11-15, 06:00 PM	#4
audicoupeparts Senior Member Classic Audi Club Member Join Date: Mar 2008 Posts: 1,161	Thanks Thanks for the links guys I did think fuel related as ok at idle Will do the tank WUR and metering head filters Any where available where I can buy new filter for WUR ?

03-11-15, 04:39 PM	#2
Jake Blight Grown up member Classic Audi Club Member Join Date: Sep 2015 Location: Cornwall, near England Posts: 881	Have you read this thread? It may be of use. Good luck sorting it out. http://www.classic-audi.co.uk/forum/...ad.php?t=24516

04-11-15, 08:57 PM	#5
audicoupeparts Senior Member Classic Audi Club Member Join Date: Mar 2008 Posts: 1,161	Bump Any ideas? Also been told about ignition module On type 85 anyway was under driver side dash on Ali plate Is there one on b3? Behind kick panel maybe Need to get this running right for the MOT

04-11-15, 09:41 PM	#7
audicoupeparts Senior Member Classic Audi Club Member Join Date: Mar 2008 Posts: 1,161	Starts fine Issues develop once been run for a few minutes Gradually refusing to rev until cuts But restarts and idles fine Really want it MOT d for autumn Sunday morning blasts before it has to be sold on

05-11-15, 08:11 PM	#8
sam Grown up member Classic Audi Club Member Join Date: May 2008 Location: North east Posts: 778	fuel pump/filter?

05-11-15, 08:28 PM	#9
quattrostyle 4 ring whore! Classic Audi Club Member Join Date: Feb 2010 Posts: 2,188	It's your K-Jet, most likely the 'piston' that moves up and down and is operated by the round flap. Remove the metering head from the top of the airbox, turn it upside down, then you see 2 bend pieces of metal, open them up and take the piston out, don't loose the spring that's behind it! Clean it up and polish it and put it back in. However now I come to think of it, try to adjust the CO first though the small pipe on the metering head. This helped on my 90q the last time I had this issue. The screw can be turned with a small hex key? Anyway, start the car and keep it running by operating the throttle, give the CO screw a half turn or less left or right and see if it helps.

05-11-15, 08:31 PM	#10
dgacampbell Senior Member Classic Audi Club Member Join Date: May 2011 Location: Co.Armagh, N.Ireland Posts: 1,442	Check if yours has an o2 sensor? Do the exhaust fumes smell very rich when it starts to die off? I had a problem with my car at the start of the year, same sort of symtoms, turned out to be a faulty o2 sensor, for whatever reason it was telling the car it was running lean and richened the mixture until it wouldn't run. just a thought.