Burnt ECU and need help finding what burnt it

[Reese300]

Hey there guys, new to DSMTuners and glad to finally have made an account. I just recently bought a 1997 2G GST for $1200. the guy i bought it from said it wasnt running because of the coilpack. once i got home i tried to crank the car but nothing happened. i know i was pressing the clutch all the way in, so i figured it might have a dead battery. i connected the jump starter box to it and tried to crank it. again nothing happened. none of the dashboard lights turned on either. the next day i connected the scanner to try and see if the ecu would give me any codes, but it wasnt linking. i decided to check the ecu to see if it was plugged right. while i was there i opened up the cover and i saw that there was a burnt spot on the ecu. i figured this was the cause of why the car wasnt starting. i have already ordered a new ecu but i know i have to find what caused it to burn out. any ideas?

 

[steve]

Without some idea of where it burnt we would be guessing. Pictures help.

The typical places for a 2G ECU to be burnt are the ISC drivers, the drivers for the other solenoid drivers, and the sensor ground.

http://www.ecmtuning.com/wiki/driver01

http://www.ecmtuning.com/wiki/blownsensorground

 

[Dsmkauai]

Take it out send it to ecmtuning and they will fix and tell you the problem. Or I actually have a good 97 ecu I'm never going to use. if you want to buy pm me, I'll hook it up bro. But you still would need to identify what caused the issue in the first place. You def don't want to fry another ecu. Welcome to tuners bro

 

[Reese300]

Thanks for the reply guys, I took the ecu out again and here are some pics.

 

[steve]

Sensor Ground is toast and the other is a transistor driver for something I no longer remember off-hand.
Tom and Dave at ECMtuning should be able to take care of you.

Either someone reversed the battery or you had/have a wiring short. Many of the failures of the sensor ground I saw were due to trying to use a universal O2 sensor and miswiring it. The other transistor being blown would suggest a larger wiring problem or people trying to diagnose the no-start and connecting jumpers where they shouldn't be connected.

 

[Reese300]

Ok so my replacement ecu comes tomorrow, do you think I should replace the o2 sensor and wire it correctly or is it something bigger that blew the ecu?

 

[steve]

I can't say.

If this were my car I'd break out the multimeter and the wiring diagram to check the ECU circuits before installing a new ECU and risking burning it up.