dingle 0 Posted September 8, 2016 (edited) Hi guys after some advice if possible please Have a slight rough start for split second when starting car from cold.mentioned it to someone who deals in repairs on Corrados and they mentioned the isv so I bought a replacement slapped it on and car would not idle at all. So put old one back and idled ok again. Contacted company they said could be faulty so they replaced it. Put new one on and car today it started but idled very low for a second or so then used normal i left it for a few hours. Took car out at 8 started at low idle again went less than half a mile stopped the car did an errand and got back in and car wouldnt idle at all any ideas as I see the adjustment screw is covered in glue or something to stop adjustment just like the old one. Cheers for any help Edited September 9, 2016 by dingle Correction Quote Share this post Link to post Share on other sites
easypops 8 Posted September 8, 2016 It'll help if you say which engine you have and you might want to put up a picture of the ISV as I can't think of a glue covered screw on mine? Quote Share this post Link to post Share on other sites
seanl82 23 Posted September 9, 2016 If it's a cheap ebay replacement just bin it mate. I had 2 faulty ones so just bit the bullet and bought a new bosch one in the end. Not cheap but sorted my problem instantly. There is a small nut covered in wax/glue, but not sure if it's for adjustment. I'm sure if it was someone would have done it before. If you want to try though, knock yourself out! Oh, and if your original is playing up, clean it all out with carb cleaner. Sometimes helps! Quote Share this post Link to post Share on other sites
fendervg 30 Posted September 9, 2016 (edited) Normally (if it's a VR) the car will idle slightly high on cold start and then settle down to in or around 650rpm after a minute or so. I would say you need to clean your ISV and throttle body housing and check for any vacuum leaks, especially look at the intake boot from the airbox to the manifold for hidden cracks. It's quite easy to measure the inlet manifold pressure with a cheap pressure gauge and some vac hose and a plastic t-piece connector. Also get the car scanned with VCDS and see if there are any error codes returned. You most likely have a dodgy sensor, leak or intermittent wiring fault somewhere rather than a faulty ISV. The ISV is really just there to bring the idle up a little when there is no throttle applied and to stop the engine from cutting out at low RPMs. I've never seen a faulty one cause a low idle and have owned three similar vintage cars with the same ISV design over the years, although I guess it is possible - low idle would suggest not enough air getting in I would think. Edited September 9, 2016 by fendervg Quote Share this post Link to post Share on other sites
dingle 0 Posted September 10, 2016 All can really say is put 2 isv's on and neither would run the car unless u throttle it and on putting the old one back on it starts and is fine just has an occasional lumpy start first thing or it cuts out sometimes Quote Share this post Link to post Share on other sites
sixohfour 10 Posted November 6, 2016 one problem i cant figure out for the life of me (to do with isv) had the black filter capsol blow up on me when i start the car, no idea what that part is called but i have had 2 do the same thing how this could happen but its a real bitch to replace Quote Share this post Link to post Share on other sites
