Hi My '78 Westy 2.0 EFI engine has stopped working and, after checking the fuel pump and injectors, my repair garage says it looks like the ECU is faulty. They said this unit is no longer available from VW and they will try to get hold of a used unit, maybe without warranty. It's not clear whether they will be able to do this. In Spain, spares for classic vehicles are always a problem. Also I think in Europe these vans had carbs rather than EFI. My one came from California, maybe this makes things even more difficult for me, I don't really know. The Haynes manual says they all have carbs, including the 2 litre. I'm not sure I'd like to switch to carb because they seem to use even more fuel, also I don't want to spend even more on the conversion. Do you think Ebay is worth trying in this case? Would that be Ebay UK or US? Are spares for Californian vans easy to find in UK? Any aftermarket alternatives to this ECU that an average repair garage can fit? Cheers, Alex
FI was sold in Europe in certain markets like Switzerland and as an option. There are a few places that will repair faulty ECU, like BBA Reman in the UK.
Try @pkrboo he might have a spare to sell. You can also try parts emporium (google it add vw spares to the end) mega bug and our own @davidoft might have one. There’s been a few threads in technical where they are taking the backwards step and going to carbs. See if they are selling.
Hi @alez I’ve still got mine somewhere off a 2 litre Californian bus. It was changed to twin carb before I bought it but the ECU was still in situ. I can look it out for you. I don’t know if it works but am presuming as still in situ it did.
Thanks so much much everybody for the valuable comments. You are amazing. Just now I need to wait until the repair garage has a final say with regards to procurement, but I'm relieved to find out I have options if need be. @davidoft, I don't have an ECU number for now, but I'll obtain it from the repair garage if they end up saying they haven't been able to source the spare. I'm on electronic ignition.
The guy who runs the repair garage says my van is a runner again, but not reliably enough... runs for a while, then stalls, apparently. He said he got the the original ECU repaired. Visual inspection showed that two capacitors were damaged, but I really wonder why (*). I wonder if the root cause is still hiding. He also said he's ordered some different ignition ECU. I guess it must be some aftermarket job. I guess I'll just leave him to it for now. (*) Some thoughts on this from the electronics design engineer in me in case you may be curious I guess that, by "capacitor", he meant an electrolytic type. These fail open both open circuit and low impedance. Open circuit: typically over time (ageing), with no apparent damage, so that's not what happened. Low impedance: typically because of a sustained overvoltage (when subjected to a voltage above their maximum rating), with evident damage, as they explode or burn (and they smell, too!), so that's more likely. These components are normally derated, meaning that they are made to work sensibly below their voltage maximum rating. So it looks like failure propagation to me, that is, whatever internal voltage rail in the ECU went too high due to a failure and these caps failed as a result. Strange as the van showed hesitation (power delivery glitches, sorry for not knowing the English term for that) before coming to a complete stall.
Electrolytic capacitors can fail with going high resistance/ low capacity too. Heat and time. No electrical leakage but strange behaviour , as the equivalent series resistance goes up, so they start adding 'lead' to a filter circuit where they were previously present to provide 'lag'. Makes a control loop go unstable. As a part of this process , they can produce internal gas pressure that blows the seals so they start to dry out. Fortunately with the old ECUs there are no specialist components in them so fixing them is a definite possibility.
Interesting. I wouldn't have thought that these may be used as part of a closed loop. Or maybe you mean as output capacitor of a supply with a feedback loop. Ageing aside, the latter case is probably one of a few cases where a parasitic can make your life easier in electronics design... ESR contributes to total loss, BUT generally helps stability, contributing to gain and phase margins ¿?
Guys, I'm so desperate :-(( The van is still in the repair garage after 2 months. They say they need to replace something but they are struggling to get hold of the spare. I've uploaded two photographs I took yesterday. The top lid has the code "0280200020". Can you please tell me what it is, whether it's difficult to procure in second hand, and how much this bit may cost? Thanks for all your help. Alex
I wouldn’t panic too much. If your bus is in good condition generally and you still want to run it , there are lots of options. Lots of people, including myself, dumped the whole FI system. Some will argue with this idea. Anyway I’m sure an air flow meter will be available or repairable.
This one was for sale in Spain back in May, might be worth contacting them if davidoft doesn’t have one. https://www.bugbus.net/fr/classifieds.html?cmd=detail&id=36065