For the last 2 months I had been experiencing hard hot starting/stumbling and some other weird engine behavior broblems. My car finally stalled last monday. I towed it to my trustworthy mechanic since I was quite busy with a friends wedding. I had checked almost every single sensor before that stall and I couldn't figure out what was causing the problem. I also gave him the old 511 ECM which I had replaced about 6-7 months ago with a used 544 just in case. And it seems it solved the problem.

The story behind my old ecu is that for almost 2 years before now it started giving me some weird problem. The engine will momentarily cut-out for a brief half second and on the same time I could hear the fuel pump relay clicking. Sometimes when the weather was wet it would do it more often. Some people on the swedishbricks list told me that the ECU was going bad....the relay and the 2 spared I had were fine. I found a used 544 ECM for $20 (with shipping) and I replaced it right away. The car had started working fine after that replacement.

Some time ago I decided to open up my old 511 and take a look. To my surprise I found 2!!! cocoons inside the box. One was under the injector drivers heat sink and the other close to the connector.
I seems that some kind of small worms found their way into the ECM and decided to make their nest and they died. Anyways..the bottom line is that I cleaded the old ECU and thank god I kept it as a spare. I assumed that the cocoons were conducting electricity when the weather was humid and warm

I am planning to get another ECM as a spare also.

Does anybody have any experiences with the 544 ECM swap? I beleive I read somewhere that some 544 and later 240 ECMs were failing at a noticable rate due
to overheating problems.

Any ideas, stories

Thanks