An update on the mysterious no start on the 89 240. I tried getting fault codes from the OBD port on the driver side strut tower. There is absolutely no response from the computer. Not even 1-1-1 for no fault in test port 2. In test port 6 there is also no response from AC or TPS. So I guess the 556 ECU is completely fried? Does the ECU ground itself through its mouting to the car? I have it plugged in but it is no screwed into the frame at its mouting point. I checked all the ground points in the engine bay.
Thanks again for the help.
Justin

So the 566 ECU was busted after all. The closest thing I could find at the JY was a 91 740 NA with 160k miles and a 933 ECU. Out of desperation I bought it and hoped for the best. When I first tried the new ECU the engine still wouldn't fire. Then I found a blown fuse in the engine bay. I thought DAMN I'm an idiot for not checking this fuse before I spent $30 on a new ECU. I reinstalled the old 566 ECU and replaced the FUSE. Engine fired for a split second then died again. DOH! The new fuse was blown yet again. As a last ditch effort, I installed the new 933 ECU and replaced the fuse for the second time. Engine fired on the first try and idle was smooth as butter. After driving the car for a nice 10 mile trip with the 933 ECU I wanted to double check the diagnosis. In went the old 566 ECU yet again. For the third time the fuse blew and no start! So I guess that's it then. The 566 ECU kills the fuse. I don't know why, I don't know how but the 566 likes to murder this fuse. On the bright side, my friend was right: Any LH 2.4 ECU will work on the 89 240. Maybe even a turbo ECU. Plus the engine is soo much smoother. I can't believe it. It really feels like a new car. Thanks to everyone for all your help.
Also a special thank to rhaire for making THIS very helpful ECU list.
Justin

Old 566 aftermarket ECU the previous owner installed.


The fuse in question


My new used 933 ECU from 91 740 in my 89 240. Who knew it would work?

I've had 2 consecutive faulty rebuilt AMMs from Programa. Their 3 year warranty is a great selling point, except that they don't work right out of the box! Well in fairness it ran at idle for a few minutes... FWIW I've also heard nothing good about Python's rebuilt AMMs, though I think their ECUs are okay.
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Chris, Dartmouth NS Canada 70 M-B 280SE, 83 245DL, 84 244 turbo, 90 780 turbo, 92 VW Golf

I had a rebuilt Programma ECU that only lasted a short while as well.

i think also it can be used for 2.4 with egr. does your car have the e.g.r. setup? if not is your check engine light staying on? thanks

You are testing with the ignition "on", correct? If so and no codes, you have a major ECU fault.

Hi,

Not necessarily any ECU failure. Had same no-response situation in 940 with LH2.4. Engine had suddenly started to run very poorly. Turned out to be one of the injector connects that was half-loose. Either a response here on the board, or in the FAQs, mentioned that you can have a no-response due to oxidized leads, for example at the main board connector leads. I never dug into that, since my problem was easily fixed. Checked again 1.5 years later, still no OBD signals, car ran like a beauty.

IMHO I would check the main board connector for oxidation, maybe my problem was just one oxidised lead, maybe you have also a, for function, critical lead oxidised. Let´s hope for a simple explanation first, before fearing the worst.

GustafKalle

Interesting: do you mean at the main ECU connector in the right hand footwell?

Yes, behind the plastic side panel under dash just in front of the lower part of the right side front door