please point out if im talking crap here,its been a while since i enjoyed a valver vac pipe? from the ecu? is it ok? no obvious holes anywhere?
Yeah, that's all good...even went as far as connecting the ECU pipe directly to the vacuum source, putting a y-piece just ahead to the ECU and then taping a boost gauge to my windscreen, just to see if there were any fluctuations when the problem strated to occur.
Holy sh*t, I think I've cracked it!!! Drove to work this morning not letting the car idle and she ran great, so I thought sod it, I'll disconnect the ISV and see what happens. I wound the idle up a bit with the brass screw and popped the plug off the ISV and bingo....she's running lovely. Just done about 25 miles and she didn't miss a beat. Don't want to get too excited cos I don't want to tempt fate. Anyways, it looks like either the ISV itself or the control module has gone bad, but I had no idea the idle control system was connected to the main ECU in any way.
At least you`ve found a start! only reall way to test now isd to replace the isv bits with known good ones really. You can run without the isv plluhgged in but winter cold starts/ cold idle will be a but of a swine..
You're not wrong! Car fires up on 2 cylinders when its cold, a good rev clears it but she still idles like cack until she's warmed through. ECU acted up twice yesterday (but only when cold), but the rest of the time its been perfect. Gonna overhaul the ISV system component by component, hopefully one of them will be at fault.
ISV control modules are quite often at fault for these problems arent they? Or so ive read since ive been researching 16v's.
I really hope it's just going to be a case of swapping a particular component. Thankfully my mate's got a spare Corrado I can borrow bits off. I actually unplugged the ISV control unit today and it didn't make a blind bit of difference! Edited by: MillSpeed
"I actually unplugged the ISV control unit today and it didn't make a blind bit of difference!" I think that's the problem then! Same thing happen on my 16V, swapped them and bingo! I have a good working spare if you need to lend it and test it, just cover postage
Mate, you are the don! I'll PM you my address now. EDIT: You're inbox is full, PM me how much you'll need for postage etc. and I'll send you a cheque or paypal you or summit. Edited by: MillSpeed
Just tried swapping the ISV control unit and closed throttle switch (thanks again kev!), still no joy. Car is steadily reverting back to its old ways, even with the ISV disconnected. I'm properly running out of ideas now, got the ISV itself left to try and a couple of other bits but after that I'm officially stumped. I'm actually tempted to see if the polo distributor I've got (with vacuum advance and mechanical points!!) will fit on the KR head.
No luck disconnecting those connectors then? bugger! One thing i forgot to mention, did you take the throttle body off and really clean it out, especially the idle holes?
Actually, it was fine on the way back so maybe disconnecting them has done something. We shall see, I'm not going to get my hopes up tho! Tried to get my throttle body off, but the b*stard allen bolt things have rounded out, they ain't goin nowhere!
have you tried cleaning the isv m8? you can just pop it into some petrol or similar and give it a good shake about,even wd40 can help. does it buzz with the ignition on?
Yeah, washed it in parafin...might be worth doing again tho. It buzzes too. Do they buzz continuously, or only at idle?
The saga continues.....I've practically disconnected everything not essential to the engine running (ISV sytem, WUR + 5th injector, overrun cut-off valve) and although the problem has gotten much better it still occurs from time to time. Tried another ISV, as soon as you plug either one in the engine goes nuts, I mean it really doesn't want to run. I've also noticed the rev counter going crazy, especially on the motorway, jumping all over the place. Does anyone know if the rev counter feeds back any information to the ECU? I've fitted a brand new hall sender so it's not that, was thinking either the signal coming from the hall sender is being interrupted or the rev counter itself has gone dodge. Edited by: MillSpeed
Not read all the thread.. have you checked the earths that are on the corner of the head? When the rev counter goes nuts does the engine stutter/misfire? Have a look at the main ECU plug, they can corrode (terminals go all green and manky) especially if the scuttle drains are blocked and the scuttle gets flooded [:^(] edit - read you've looked at ecu wiring. Edited by: GVK
Earths are good, even ran an extra earth from the head to the -ve terminal on the battery. It'll have a cough every now and again, but the rev counter wiggin out doesn't have any effect on the way the engine runs. Although the other day when I pulled off the motorway (after the rev counter had been having a particularly energetic session) the problem immediately re-appeared when I pulled onto the roundabout, but flicking the ignition off sorts everything out.
