engine dies when off throttle

[hursleyemc]

hi hope a guru can advise me here, 1990 8V GTI. when idling engine is fine, when driving along and then throttling or or slowing down, engine dies in 2 secs. Has any one experienced this. I am in southampton area if anyone can recommend a specialist.

I have changed the oil, and fuel filters and also removed and cleaned the Idle Stabiliztion Valve (ISV), I am reluctant to try another ISV as the cost is nearly ?200 !

I would appreciate any feedback as this is spoiling an otherwise excellent car !

thanks

  JJ

[Veedubgt18v]

yeah there is a specialist near you

www.wagenwheels.co.uk


and have you checked you throttle switches on the throttle body?

if your idling is to low and the throttle switch isnt working then this could happen. do your revs bounce? or seem erratic?

[hursleyemc]

hi no I havent checked the switches, Idle is very stable now, when I got it it was a pain idle all over the place, but found some wires loose re-soldered these and it idles with great stability now !

what do I do with these switches is it a DIY or specialist area to start adjusting, cna you tell me which checks I can make, I have multimeters and things

thanks

 JJ

[helliosjon]

My 89 16V is in the garage at the moment for exactly the same problem.
I'll let you know what they say later on.

Do these cars not like hot weather or something ?

[Veedubgt18v]

the switch is a special order part from vag. is your car digifant injection or kjet?

[Veedubgt18v]

dont worry i answered my own question.

The switch is on the throttle body one tells the ecu the throttle is shut and the other tells the ecu the throttle is wide open. when the throttle is shut there must be infintie resistance across the terminals so the ecu know whether it closed or not.

rich or vr6?

im not entirely sure on this one its a bit of a mission to explain. has anyone got anything already written?

[Veedubgt18v]

i knew i would find it!


http://www.richandhazel.servebeer.com/gti/mk2/fuel/main.htm#ISV

[hursleyemc]

hi, I've taken a pic but don;t know how to post it here ? there is one switch like a microswotch but it seems a long way from the throttle pats ?

I've read your URL link recommendation and then if you can tell me how to attach, I'll upload, I guess its digi, as I had a camper which looked very similar

[hursleyemc]

Hi, this is great live diagnosis ! I've just been out to the car and checked the following

1) ISV buzzes when on and there is continuity when off across terminals
2) tried to measure across the throttle loom connnectors for 5V when ignition on, but had no joy, no volts, but I am not quite sure how there would be anyway if it just goes to two microswitches
3) checked the microswithes and they seem ok, I have a short across the throttle terminals at idle and also at full throttle, so that looks ok !!

any one else any ideas, that URL was excellent ! but I don;t seem to have highlighted an area at fault unless there should be 5V there and I have nothing, but I am sure that is a mistake.

thanks

 JJ

[Veedubgt18v]

if you want email me that pic and i will take a look

john.combes2@ntlworld.com