Still chasing idle issues. In short... is my ISV control unit (VDO box behind centre console) buggered? Having read what I can I have tested voltage with ignition on at the black lead (ignition live feed in afaik), all good with 12v. But nothing at the white/black lead which I THINK is live out to the ISV (which has stopped buzzing, no voltage at either lead on plug). Can someone confirm that the white/black lead from the ISV controller should give 12v? Thank you EDIT. Just read on another thread that black/yellow is live to throttle switch. Mine gets 12v so ok.
check the brown/white has a good earth too. also look at the condition of the green/red to the sensor on the side of the head, and make sure the sensor is ok (swap the dash temp yellow/red on see if it reads ok)
Thanks for the reply... I see you are answering identical problems on another thread so I'll watch that too. I also have everything working fine apart from 12v at the ISV white/black like geof914. Knackered? At 10 degrees resistance on temp senders was as follows: Green/red sensor 1256 ohm red yellow 1577 ohm blue white 1312 ohm Is this difference ok or would I need to check throughout heat range? Would it stop ISV working or just its efficiency? Thanks again.
check for 12v at the controller end of the white/black next for the sensors easiest way is swap the red/yellow between the others and drive it, see how the gauge behaves. and when hot make a note where the gauge sits, switch engien off and swap between the others see if its about the same. I dont have a decent chart for the gauge, but haynes has this: At 20C - approximately 1000 ohms At 60C - approximately 250 ohms At 100C - approximately 75 ohms
After reading your reply to the other thread I have connected the ISV to check voltage... was disconnected last time... I have also got a low 3.4 v at white and 0.57v on black/white. Also just noticed that it buzzes gently then goes off. If I whack it it works for a few more seconds. Used to buzz much stronger from what I remember. BUT, I also have 0.38v at black/white and 3.64 at white on the relay controller. 11.72 at the black (battery terminals shows 12.06 a bit low due to repeated starts and stops. Does it sound like the relay controller at fault?
does swppign the green/red to o0ne of the others make a difference? maybe get it charged up and see how it is
I swapped green/red with red/yellow. Same 'buzz for 10 seconds or so' but the car does idle and drive for the 10 mins I tried it up to temp like it did before... maybe intermittent issue. Not used it since as I'm also doing bodywork and it's on ramps at mo. I need to try again a few times to see if better again. It did seem smoother from cold, no hesitation which is the issue I had. I bought 1 new sensor during all the rough idling, might buy 2 more and see. (Cheap ones though not VW). I also removed an old alarm that was draining the battery which had choc blocks and loads of spliced wires. That was last thing I did but it didn't effect the 10 second only buzz, but looks a whole load neater. I haven't tried cleaning the ISV. Could this be why it works after hitting it? Thanks
possibly, its probably best to stop messing with it now until you get the car on the road to give it a proper drive. I helped a guy out a long while back out with his abf swap and he found it wouldnt idle well at all once he got all the issues fixed, told him to rag it up and down the industrial estate and it was perfect after that
Italian tune up! It has been sat a lot this year, I'll have to give it a rinsing on a B road once I've got it off the ramps.
