Faulty ECU caused No Start Help!
 

Hi guys, I had a problem the other day when my 944 didnt start. I worked through the basics of air, fuel and spark and found there was no spark. I tested all the components, which are good and then tried a spare ECU which worked first time.

Something has shortend out my ECU and before I buy and install a new one I need to find whats shorting it out. This is my 2nd ECU thats burnt out, the first was due to the wrong injectors which were running 16ohms instead of 2ohms. I installed a new one, along with the correct injectors, which solved the problem, now this one has burnt out. The first burnt ECU was the spare one i used to test to see if it would start as I knew it would do at least that.

My question is any ideas as to whats causing it or whats the first step to rectify this nightmare? Ive spent more on ECUs than fuel :-( Appriciate any suggestions please

RE: Faulty ECU caused No Start Help!
 

I would pop the ecu open and check the solder joints. Usually the solder joints crack and cause the ECU to not work. Anyone who is good with a soldering iron (like a tv repair man) can go through the boards and fix all the joints. There aren't any signs of rust anywhere on the ecu/dme case are there? If so, I would look at your battery box for rust. Water will leak through there when it rains and right onto the dme.

RE: Faulty ECU caused No Start Help!
 

Ive got a UK spec 944 so its the fuse box that is under the battery box and it was rusted through, but has since been sealed and dried. The ECU side is dry as a bone. It looks like the wiring harness caused the ECU fault due to rain or cracks somewhere along the harness. Luckly I traced the loom from the ECU and most of it goes into the engine bay and not to the fuse box, so I guess its a matter of resistance/earthtesting every wire and maybe replace the fusebox.

Is this what you would do Doc?

Ill take a look inside the ECU for damage, but it would be brilliant if it was just a joint that needed resoldering. I hate electrics on old cars, dont you agree? :-) Cheers Doc