8v K-Jet Idle problems

[1985sport]

Hi I'm about to embark this weekend on trying to track down why my mate's 8valve KJet golf is "idle hunting", quite badly actually.  Dosen't appear to have any starting problems though.

First off - what is the most likely cause? I remember a thread a while back with some reasons, but cant find it now.  I'll eliminate each possible cause as I ask him whats recently been done to the car in an attempt to sort it.

Thanks,

1985sport

[mix]

probably a split vacuum hose somewhere....

[rubjonny]

If it has an idle switch, make sure it clicks when the throttle is closed, & check the rubbber inlet boot for cracks, especially in the folds. Also get the CO & idle checked

[1985sport]

ive taken all the vac hoses and the rubber/plastic inlet manifold off to be cleaned. 
the throttle bodies are coming off today (with some persuasion - tiger seal!) as they need a clean and the idle switch dosen't click (thanks rubjonny) so its probably easier to replace the bodies rather than fanny around with the switch. (got some audi ones lying about with good switches).

Ive noticed a t-piece somewhere in the breather hoses, however one of the hoses from the T-piece is simply blocked off - i'll take a photo if i can but any ideas why this is?

Wasnt someone somewhere saying something about one of the replacement GSF parts (thermo-switch?!?) gave dodgy resistance and was causing problems?

Thanks for your help,
1985sport

[rubjonny]

I think that may have been a GSF ECU temp sender for a digifant, apparently they are pants.  Obviously not relavant to K-Jet anyway.
I assume same can be said for other senders they sell, if you can I'd go for VW senders.

As for the vacuum pipes, check this out:
http://www.moddin.net/images/temp/golf/8vk-jet.jpg

[1985sport]

vac hoses clean, a cleaned aux slide valve put on instead of the dirty one, and the idle switch changed as it appeared that the little button on the exisiting one had dropped out!
the butterfly valve adjustment screw was wound back in until the switch just clicked. it was so far out that had the switch been on there then it would not have been contacted anyway.

anyway, did all that, better but not perfect and now he's decided to change the engine for one he had around the back anyway! honestly, sometimes why do I bother?!?

cheers anyway everyone.

1985sport

[rubjonny]

Oh well eh 

[1985sport]

tell me about it!

and just to let you know the blanked off t-piece was apparently a valve that was in use for the cabin heating system, it was just blanked off as it works far better with out it now. apparently.

1985sport