k jetronic

[gofa]

hi all,i own a d plate runing k-jetronic fuel syst and have sufferd with bouncy revs,and sometimes stalling for a while now.I recently fitted new fuel pump,warm up valve and a good second hand air flow meter and fuel distributor.the only prob i have with the car now is this revs problem anyone got any ideas,or suffered the same.many thanks to anyone who can help.

[richandhazel]

How about checking all hoses and vacuum pipes etc., could be perished?

[mo3000]

This might seem far too obvious but is does happen.
If the car does it all the time eg from cold start and when its warm, The tickover speed could be set  too slow meaning that when the engine goes below 750 rpm an air valve will open in order to increase engine speed, however this valve closes again as soon as the revs go above 750. in this case you will get your bouncy revs. Try adjusting your tickover.

 Another thing it can be, if it only does this when its cold, is the auxilary air valve mounted on the back of the inlet manifold, this is a differnt valve than the one mentioned above, this gives an increased tickover from coldstart, and gradually reduces it back to the normal 950 rpm as the engine warms up. If this auxilary air valve is screwed, the engine will tickover too slow when cold thus relying on the other valve i mentioned before, giving, you guessed it, bouncy revs.

I hope this helps  

[danthevan]

Try cleaning out the idle stabiliser, quite a common fault on 8v!
Its the little box above the oil filter with 2 fuel lines going into it. Just carefully strip it and clean it. A new one is over ?100 so dont break it !!!!!!!

[mo3000]

Thats the warm up regulator 'danthevan'.

It regulates the control pressure to the metering head, which in layman terms means it richens the mixture when cold and slowly weakens it to normal, as the engine warms up. its is relativly common for these to go, and the normal symptom is crap cold running.

The 'idle stabilization valve' or auxilary air valve (same thing, on K-Jet anyway.) is the one on the back of the inlet manifold. if Either of these are f**ked you can use one off any K-jet car. GTI, A80, etc. You can even use the one off an early XR3I. Although you would probably get some bad Karma from using something that was once bolted to a bag of sh!te.

If you use the warm up regulator off a 16V, you get an extra vacuum attachment, which when conneted to the inlet manifold correctly gives you extra fuel enrichment at full throttle. This only really works best when using an Audi Throttle body though.