ABF lumpy, VW mechanic stumped!

[Classic16v]

Update on my situation:

I took my car to another garage where I have received a lot of help previously, and asked them to look into it for me as I currently don't have the time/space/tools to be diagnosing it myself. I gave him the back story about what has already been tried and left it with him. Diagnostics this time showed up the crank sensor and temp sensor (having been cleared of fault codes at the first garage, therefore these are new codes). I'm sure the temp sensor fault is due to me having tried running it with this connected, but he mentioned hes seen some trouble with aftermarket sensors recently. 

Anyway, he changed the crank sensor, which helped but didn't cure the problem. He then traced the problem back to corroded terminals on the ECU.  He disconnected these and cleaned them as best he could, but after plugging them back in the engine isn't wanting to do much at all.  Has anyone experienced this situation? My handy engine-swapper (Simeon) says the ECU plugs are in a water-tight holder (although this may have been leaking), and so the ECU could have just been damaged by removal and cleaning. Whatever the problem, it seems I now need an ECU, and I do trust this mechanic so I don't expect he would have just screwed it up.

Any thoughts/comments?  And can anyone point me in the best direction for a new ECU? There are a couple on eBay (http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2047675.m570.l2736&_nkw=abf+ecu) but do I just need that unit, or the immobiliser too? I understand they can be re-coded to my immobiliser, but how involved is that? And is it something he's likely to be able to do easily?

Cheers

*EDIT - there's quite a difference in price with those ECUs on eBay - do you reckon that's just the 'eBay shop' seller vs a private seller?

[Diamond Hell]

Make sure you get the same code at the end of the ECU.  If yours has immobiliser then you need the new ECU coded to the key, or get it de-coded by someone for £50-60ish.

IIRC AB code ECUs are non-immobiliser.  They are worth more.

[weazgti]

just scanned your first post and it says that your running the mk2 coil set up and the ignition modules been changed. Is this definaty the case? No expert but when I had the 8v engine in mine it run exactly as you described. I took off the ecu plug, checked terminals and put it back on which resulted in a non runner.
Next day it would fire once but not run until I started wiggling the ecu bracket. Took the 2 screws out of ignition amp and bingo. Run spot on, no huge flat spot. Changed it for a working one, drove it for 2 years and then threw it all away when I abf d it. I figured I'd rather just keep a spare coil for the mk3 set up in the car than bodge mk2 electrics on a mk3 engine.

[Classic16v]

So we've managed to get hold of another ECU, but the mechanic struggled to code the immobiliser using Vagcom. He used to be able to do it with his old Bosch system, but has never done it with Vagcom - does anyone have any pointers to a guide on how to do it?

Or, better yet, does anyone fancy giving him a call and explaining it.....? 

[CriticalPoint]

I had the same symptoms on my Cordy (6K2/C2) 2.0i ABF. A crank sensor sender, set of HT leads and a new ICV swap out cured it instantly.

All the best!

/ Crit

[tshirt2k]

So we've managed to get hold of another ECU, but the mechanic struggled to code the immobiliser using Vagcom. He used to be able to do it with his old Bosch system, but has never done it with Vagcom - does anyone have any pointers to a guide on how to do it?

Or, better yet, does anyone fancy giving him a call and explaining it.....? 

 Very easy. Do this

[Len]

So have you actually checked the ECU and Fuel Relays?

[Classic16v]

Very easy. Do this

Thanks tshirt2k. I've let them know and they're going to give it a try.

So have you actually checked the ECU and Fuel Relays?

Not sure Len, as it's been out of my hands for a while, and I'm finding it hard to keep up with my limited knowledge and the long list of things that have been tried! I can certainly try and find out though. Simeon has spoken to them as he has supplied the second ECU, so maybe he knows...

I had the same symptoms on my Cordy (6K2/C2) 2.0i ABF. A crank sensor sender, set of HT leads and a new ICV swap out cured it instantly.

All the best!

/ Crit

I wondered if the ICV might have something to do with it, but it seems like we're now in a situation where the 1st ECU is not working, so we'll see what happens once the new one is in. Supposedly it fired up ok with the new ECU fitted, but the immobiliser cuts it off as it hasn't been re-coded yet.

Cheers for all the comments

[Simeon]

So have you actually checked the ECU and Fuel Relays?

The garage has checked power to the ecu and pump apparently, both fine.

[danj3000]

I had similar issues with running in an old mk3 ABF of mine a couple years ago. Tried all the obvious and it ended up being the ECU relay. £11 or so from VW and all solved. These relays along with the fuel one were not particularly well made hence the high number of them failing. The difference in weight and quality from the replacement one I bought was like night and day compared to the faulty one it replaced.

Either way, best of luck!