Bobby 0 Posted February 3, 2006 Does anyone know if the isv on the kr engines are supposed to continue buzzing when engine is idling, as my car idles really bad. I've tried sqeezing the pipe that comes of the isv and the idle stays the same even unplugged the isv and the idle stays the same? How can i check that there is power going to the isv? The valve makes a short clunk when the ignition is switched on then stops and nothing. Tried another isv, dizzy and metering unit but no difference. Is the isv activated by the microswitch on the inlet manifold?I was going to try change the control module under the dash any suggestions would be great :D , i hate electrical probs :( p.s ive tried the search but cant find the answer to this Quote Share this post Link to post Share on other sites
bcstudent 0 Posted February 3, 2006 From the VW workshop manual covering the Corrado KR-engine... CHECKING IDLE SPEED STABILISATION Checking operation Switch ignition on. Control valve must buzz or vibrate. If no buzzing or vibrating can be detected: - Disconnect control valve wiring and check resistance of control valve, Specified: 3.5 - 4.5 Ohms - Disconnect green/red wire from temperature sender located on flywheel-end of the cylinder head and check resistance between the contact and housing, Specified (degrees C/approx. resistance): 0/2500, 10/1500, 20/1000, 30/700, 40/480, 50/350, 60/250, 70/180, 80/130. - Check wiring and connections and, if necessary, renew control unit (located behind dashboard above the relay plate). Is it just an idle problem your car has? Does it drive ok? The fact that the idle doesn't change when the ISV is unplugged is a good indicator I guess. Have you tried cleaning the ISV or tw@tting it with a blunt object? - these are both recognised repair techniques! I have no wiring diagrams for the ISV system but I expect measuring the voltage between the two pins of the disconnected ISV wiring will surfice as a simple power check. There's a bit in the workshop manual about checking regulation and control current if you want that info too. It's more or less what the Mk2 Golf Haynes manual says. Quote Share this post Link to post Share on other sites
Bobby 0 Posted February 4, 2006 thanks for the info mate, i'll do a power check on the wiring. From what i've been advised the isv is meant to constantly buzz, the weird thing is sometimes when the car gets up to temp the isv kicks it and sends the idle up to 2500rpm so i'm thinking its could be a duff temp sender, but the mfa reads oil temp ok and so does the water temp on th clocks? The car drives fine but just wont idle right at the moment i've adjusted the idle screw to get a half decent idle speed, the isv must be not doing it job as when the revs are dropped sharply the idle dips real low then bounces around 1000rpm before is stabilises(ish). will do the checks and bring back the findings... Quote Share this post Link to post Share on other sites
bcstudent 0 Posted February 4, 2006 The temperature sender mentioned above is probably seperate from the MFA oil temp and water temp gauge senders. It is on the 9A engine but I'd have to check on the KR to be sure. Quote Share this post Link to post Share on other sites
Bobby 0 Posted February 5, 2006 cheers you it the nail on the head with the sensor suggestion, i changed the isv control module it made no difference so moved onto checking the sensor and wiring, pulled the wirng off and the spade on the sensor came aswell. One new sensor later and the idle valve has come alive again, thank you for the information Quote Share this post Link to post Share on other sites
baff 10 Posted March 9, 2019 Hi guy's! Having the same issues. I tired 3 isv control modules, Including a brand new one. I don't understand what sensor you are mentioning in the post above? I am so tired of buying isv's. Quote Share this post Link to post Share on other sites
