oneohtwo

Just to update this, I finally managed to switch the PCV valve for the new one and that appears to have fixed the problem. Idles OK and fault codes gone from VCDS (well apart from an ABS fault that has now appeared... it never stops! 😂)

Ah that's really helpful thanks. I ran the test and the throttle angle was reading 14.1∠° And when I revved and came off the throttle it went back to 14.1 and stayed there so I guess it means that's all fine from the pot side of things? Haven't had a chance to switch the PCV out yet to rule that out.

Ta, will have to get VCDS out again and have a look. I take it by TB pot, you are referring to potentiometer? The new development, is that the issue seems to have become slightly intermittent. Drove it twice over the weekend and the problem didn't seem to be there. But then it returned this morning, after it had idled fine for a minute or two.

Cheers all for the advice. First port of call is the PCV as that needs replacing anyway. I have sourced a replacement for an eye watering amount... to be honest I didn't really want to pay the money as it's basically profiteering, but I also didn't really find another solution and don't have too much time to devise an alternative. If that doesn't fix it then will start to cycle through the options above, general leaks (Although I don't have a gas torch and not sure the neighbours would be keen!) MAF, FPR, etc... Apologies, what's MVB?

Did a scan with VDCS and returned error code: 00533 - Idle Speed Regulation (10-10 Adaption Limit Not Reached - Intermittent) Now the only detail for code 00533 on Ross tech is 00533 - Idle Speed Regulation (Adaption Limit (Add) Exceeded) I am not sure what the difference is, but the possible symptoms on Ross Tech are air: Air Leak between Mass Air Flow (MAF) Sensor and Engine Injector(s) faulty Fuel Pressure Regulator faulty Throttle Body faulty Intake Air Filter dirty So could well be the busted PCV as we though. Only other one there that could be at fault is the FPR, as the others should all be pretty new/cleaned/refurbished.

Update to this, I have a suspicion it might be the PCV. I noticed mine seems to have gone as oil is leaking out the bottom of it, and could be letting in unmetered air which has messed up the idle settings. I also stumbled on this old thread which seems to have had a similar problem. Replaced PCV and FPR on VR6. What a difference. - Engine Bay - The Corrado Forum (the-corrado.net) Naturally it's a NLA part of course... so will need to investigate alternatives.

Just tested and I've got 12.78 volts, so all seems good there. It had some good use yesterday so the battery should be fully charged, but starting it up the same thing is happening. Unfortunately my VCDS cable is at my parents house so I can't check that either. Don't know if the replacement ICV isn't quite right, although I don't see what would be different about it and the fact it worked perfectly for almost a month with regular drives suggests it should be fine.

It was no more than a week so I'd hope the battery was still OK. Its a good strong Varta battery that's never been an issue before, so I don't know. I too used to have problems with the battery going flat when I used to use Halfords batteries, but since upgrading years ago it's never been a problem. Engine turns over strongly as well. Presumably the maintenance pack you have has to be connected to the mains?

The poor idle has returned for some reason. It's exactly like it was when I was having issues after swapping the ICV. It's been fine for weeks, but the last couple of times I have started the car after not using it for a couple of days the revs have been hunting, and even stalling. But as soon as I start driving it sorts itself out. I'm a bit stumped. It's almost like the ECU has forgotten all the settings in between uses. Haven't disconnected the battery, or changed anything with the engine. It just spontaneously started again. I used to have the Ross-tech/Vag-com on an old laptop so I might see if I can find that and see if there are any fault codes outstanding. Anyone else got any ideas?

Ah it's gone chap! Oh I certainly don't doubt that's how yours came from the factory, my working hypothesis is they swapped over the pump design at some point in the production run for the bigger style, or just used both interchangeably. Not a biggy either way. Anyway, had a good weekend on the car. Picked it up from Longlife on Sat morning with a new exhaust. Looks pretty good and the early indication is that the drone/boom is much improved! They put a bigger mid section and back box on it, but as a bonus they cleaned up and kept the old tailpipe I had from Infinity, which saved some pennies and more importantly had some sentimental value. Couldn't fault the service either. Not much to see as it looks pretty well the same as before, but that's what I wanted. And then I got to work sorting some plastic trim. The steering wheel surrounds has been rattling about for ages, and no wonder when I got it off all the screw housings were snapped off, as well as some tabs so it was just loosely sitting there. I've found this plastic repair product called Plastex, which seems to work quite well. It's not the neatest to use, but it holds strongly: Repaired the screw housing on the left, but the one on the right was unfortunately beyond repair as it was much flimsier. Also repaired all the prongs, which the product works well on. Seems as strong as new. Then put in some foam and neoprene tape on all the surfaces it contacts something else and put it all back together and no nice and solid with no rattles! Gradually getting them all... think it's just the C-pillars that need doing now. Also used the Plastex to repair the rear seatbelt cover that a garage broke. It's hard to tell after the repair, but basically all that was surrounded in red was broken out. All of that is new material. Then gave it a spray black and it's come out pretty well, despite me drilling the hole off centre! I am pretty pleased with the results considering it couldn't go back on the car before.

Ah nice. I was really surprised the BBS are 15" - I thought from a distance they were 16s until I got close. Look good. They definitely look better than the Speedlines which look a bit puny at 15". Looks good anyway. What do you have it lowered on, it's got a good stance? The other Corrado in the main car park you saw was more than likely mine. Didn't see any others and I left quite late. I'd definitely go back, was a good day out.

Popped along to the Scramble! on Saturday and saw quite a nice clean 16v in the pre-90s car park. Anyone on here's? Not sure what that colour is, but don't think it's that common. Good event overall, anyone else make it along?

So I took it into Longlife for the guy to have a look and his assessment is the Cat is fine. The smell was attributed to oil burning off, and the system was covered in it. I assumed before I did the engine build that the smell was oil burning from the various leaks everywhere, so I think it is still all over the exhaust from that. Plus I do still have a small leak from somewhere around the sump. He reckoned you'd really know if the cat was broken as it'd be running horribly, plus it has just flown through the MOT on emissions. So on the one hand good to know, I can keep the OE cat and it's one less expense. However, I am still not sure why I am getting so much heat coming through into the cabin. The heat shield is all intact under there and I am pretty sure the trim around the gear level shouldn't be getting hot from it. I certainly don't remember it happening when I first had the car, I only started noticing it when the engine was really worn and tired before the rebuild. It's noticeable as well, like holing a freshly brewed mug of tea. Anyone else get this?

The Loctite fix seems to have done the job for now, so that's something.

Yes indeed, thanks both! I think it was certainly a case of when you're in that despondent mood immediately after something going wrong, you need a clear impartial view from someone else, and a sit down with a brew. I agree about the Canada forum, used to use that quite a bit for many jobs. I don't think I came across RW1, apart from finding the odd historic post when I am searching for something, but always sad to hear of the passing of an old stalwart.

Yes that's done it. I thought it needed a drive to learn the values, and if I hadn't bashed the car in front trying to pull away, which was my own stupid fault, I may have been OK. Managed a short drive with a variety of speeds - difficult to follow the procedure in the wiki exactly around London, so had to do the throttle in 2nd and 3rd instead of 3rd or 4th, what with 40mph being the maximum around here, but I think it's all worked. Runs well, idle is absolutely fine. Drops straight to about 600 rpm and sits there solidly like a rock. Felt a bit better driving slowly in 1st. Sometimes used to bounce around a bit on the revs and feel jerky, but feels smoother. So success for the part! Just a shame I had to add a scrape to my bumper in the process, and now have deal with the neighbour...

Ah, thanks didn't know that was there. I thought it needed a bit of driving to sort but could barely get going and left it. Will see how that works.

Hmmm, disconnected the battery to reset the ECU and that's made it worse. Doesn't idle properly at all, sits there hunting stalling, hunting. It may settle down but then as soon as you give it some throttle to move off it starts again. Managed to knock the car in front as I was trying to give it a drive to see if that would help as it was uncontrollable so rounded off a great start to the day! I think it may be a no-go for this part unfortunately, and I'll have to put the old one back on.

I may have spoken too soon on this - moved the car a short distance the other day and noticed it had started hunting on lifting off the throttle. I haven't adjusted the dashpot yet as I prefer to try one thing at a time so I know what fixes what, so will look into that. However, as it wasn't hunting quite as badly on the old part not sure this would be the issue. I will also just disconnect the battery to reset the ECU - it might have been used to dealing with the old part not functioning perfectly.

Yes indeed. We're not all lucky enough to have a VSR though! How does the VSR get around the problem - I assume it uses the same throttle body? Anyway, fitted the part today, all works fine with a nice strong idle. Can't say if it is any better than before for certain but it felt like it settled down to the correct idle instantly rather than hunting around for a bit. Should be more reliable anyway! Really good find this, thanks fella. For confirmation, the two parts side by side:

It's arrived from the US! Hopefully will get a chance to fit it this weekend. Not expecting it to make any huge difference, as the stalling issue is pretty infrequent, but we'll see! Will be nice to know it is a brand new part as well.

I've convinced myself that the one on my car originally when I bought it back was the long thinner one. Interestingly if you search for that part number (starting 034) you will the replacement parts from other manufacturers look more like the new Bosch ones we both have. Only place I could find one not second hand that looked like it is here: (40) 111016 Electric Water Pump T4 91> – VWS Car Parts (vwsonline.co.uk) So it seems that particular design was stopped at some point. Almost tempted to buy that one just to see! I may have another go at stretching the rubber over the black plastic, although it seems to hold in place well enough for now - it just doesn't seem right to have to stretch it out of shape like that. Long term I like the look of the billet ones although that is quite pricey for a bracket!

Additional water pump vr6 VW Golf 3 PASSAT CORRADO AAA ABS Water Pump 251965561b | eBay Here's the 251 965561B which looks identical to yours.

Oh look at this. I did some digging around and found these: Genuine Volkswagen Audi - 034965561C - Auxiliary Water Pump (034 965 561 C) (ecstuning.com) Additional water pump VR6 VW Golf 3 PASSAT CORRADO AAA ABS Water Pump 034965561C | eBay Part number 034 965 561C not 251 965 561B. The ebay listing says it's for a Corrado, the ECS doesn't, just the Passat, but still the VR6. But you can see the plastic lower bit is much smaller, and there are no screws, so the rubber rings would slide all the way down the metal shaft, further than both the Bosch and old GSF one. That would make it fit as I remembered, so I wonder if that was what was on my car originally. Also makes sense about why the plastic GSF didn't fit properly either, because the screw housings were in the way. Maybe they sent out both parts on different cars depending on what they had available? Could your lower ring be bigger in the first place not just stretched. (Sounds even worse now! 🤣)

Hmm, yeah I see what you mean. Looks like you're right, and it's the same part number. But now I am confused in several ways! Looking again at my old GSF part, the all black plastic one, you can see that the rubber ring would slide all the way down to the where the screws sit, so the same place where it would sit on the new Bosch one if you got it over the black plastic. But the old one didn't fit properly either! And I am certain when I originally fitted the old black one I compared it to the one I took off the car and it was different, the one I took off the car being longer. Unfortunately it was about 10 years ago, and I don't have any photos of it, so I could be mis-remembering. I distinctly remember trying to force the rubber ring over the screw holders on the GSF one though... I did try to get the rubber ring over the black plastic on the Bosch when I fitted it, but it just would not go. I'll have to have another go!