Car keeps blowing ECU's... why?

[shelbyz]

About a year and a half ago my 6bolt swapped 93 TSi AWD wouldn't start. It wasn't getting spark. Everything was in good shape, so I attributed it to the ECU. I got a known working ECU from a friend, and when I tried to use this one in my car, the car wasn't getting fuel but had spark. The car would start and die on starting fluid and when I threw on the old ECU it was getting fuel again but had no spark.

I ended up having one of the ECU's rebuilt and the car fired right up and was fine when I parked it for winter. Last summer, the car needed some work before it came out of storage, but wouldn't start again. This time a new battery was all it needed before it fired right up and was good for the rest of the summer. My alternator started going bad, so I parked it and figured I would change it out this summer.

Well we've had some nice weather here in MI, so I decided to get the car out of storage. When I first went to start it up, the battery was dead. I hooked it up to a good battery and everything works. It turns over great, but wont start. It won't start on starting fluid either. My guess is that it's not getting spark again. Also when I put the key in the on position, I get no CEL.

Why does this keep happening?

 

[bryanwheat]

It's hard to tell without seeing what is wrong with the actual ecu. Pull it out and pull the cover and check it out. If there is no spark i would suspect that the caps have leaked out on the board. There could of been corrosion on the board that wasn't neutralized that caused a trace to be damaged. If there were a wiring problem than the ecu would likely get fried with the car running and not when it is sitting.

 

[Mach1TaloN]

After storing my car in a barn for a winter, i found mice got into the car. After trapping them some of my stereo wires were chewed up. I couldent leave it to risk so i pulled the dash to search for damaged wires. Good thing i did! There was 3 or 4 wires on the main harness chewed. Good thing there was no battery on the car to begin with. But id say it wouldent hurt to check your harness at the exposed points (untaped/unloomed). Given your car sees a lot of storage time. Just a suggestion. Good luck.

 

[afterburn]

have your alternator checked i had a friend who kept blowing ecu's had his alternator checked and it was putting out 18V. Turns out the voltage regulator had gone out but it kept charging and blew the ECU about 4 times before we found the problem.

 

[bryanwheat]

have your alternator checked i had a friend who kept blowing ecu's had his alternator checked and it was putting out 18V. Turns out the voltage regulator had gone out but it kept charging and blew the ECU about 4 times before we found the problem.

That would make sense if they were going bad with the car running. His are going bad with the car sitting.

 

[92AWDHX40]

gotta start the car from time to time, keep everything functioning.

 

[miguelmcv]

Is it your ECU?.
Or it could be you CAS.

 

[habitatguy187]

I popped mine twice before I realized I had screwed up my 2g mas (in a 1g) wiring. The ecu was salvageable though thankfully. Bad grounds (I've heard), MPI relay, who knows?

 

[DSM1G90]

Yep, ususally bad ground will blow the drivers in the ECU.

Why it's a good practice if you work on sensors, disconnect the ground connection from the battery.

Been there and done that - learned the hard way.

DSM