ecu smoking.. help!

[1BADBIRD]

About a week ago while driving i noticed a burning electrical smell, abd then a lil smoke. I then stopped the car pulled pulles the radio. noticing nothing, i started the car and drove on. yesterday , the same thing! pulled the radio and noticed nothing! well..... today i pulled the ecu. all i can say is.. I GOT PROBLEMS! take a look for yourself! does anyone know why it did this? what do i need to fix? I have had the ecu caps replaced about a year ago. I have had a safc hooked up for about a year and a half. i just rebuilt the motor about a month ago. someone please help!

 

[steve]

Classic case of a shorted ISC or the wires to the ISC shorted to 12v. It's clear that IC105 and IC107 are toasted. I can't tell if the others are fried from something else or from the heat when those two went up in smoke.

Steve

 

[1BADBIRD]

thanks man. what do i do? just replace the isc motor? and how do i find out where it is grounded?

 

[1BADBIRD]

and man this things stinks! how do i tell what else is damaged?

 

[steve]

thanks man. what do i do? just replace the isc motor? and how do i find out where it is grounded?

It's not grounded. If it was the ECU wouldn't have burned up since the ECU uses these drivers to pull the signal lines low, something is shorted to battery voltage. That can be the ISC coils, that should have about 30 ohms resistance, or the wiring harness. The first thing you do is disconnect the ISC and measure the coils resistance (search, I'm not going to repeat the procedure here), then with the ECU and the ISC unplugged you start measuring the resistance between the wires to make sure none are shorted together in the wiring harness, last you check each to make sure it didn't short to a power feed somewhere else in the wiring harnesses.

The odds are that your ISC coils are shorted, but you should check the wires too even if the ISC is bad just to avoid buring up another ECU if you missed something.

Steve

 

[1BADBIRD]

where can i go to find a GOOD example of how to measure the ohn resistance of the isc?and to check the harness from isc to ecu?

 

[goran]

all you have to do is look at the vfaq. Good luck!

http://dmtalon.v8eaters.com/ISC.html

 

[1BADBIRD]

is the computer any good? considering the heat danage and etc...it looks fried..

 

[steve]

is the computer any good? considering the heat danage and etc...it looks fried..

It is fried but it's hard to say from these pictures how much is smoke damage and how much is actual burned circuit board. Also no view of the bottom of the board to see how much heat made it through and how many traces vaporized.
If the board isn't actually burnt and there hasn't been a power surge that took out the CPU then cleaning and replacing the drivers may be all it needs. If the fiberglass of the circuit board is burned you might want to look for a better ECU and donate that one to the salvage for spare parts pile.

Steve