New ISC, Now car wont start....

[Coolhawk00]

Hey guys. I had an idle problem with my 97 gst 6 bolt swap and i was thrown a cel code for the isc valve. So i replaced it and after letting it run for a while it seemed to do good. Then i let it sit for an hour and tried to crank it and nothing happened. I did key ON test and the cel comes on then goes off after 5 sec and stock boost gauge moves so i dont think its the ecu. Any ideas?

 

[DSM1G90]

If you shoot some starter fluid in the intake and if it fires up immediately then runs super rich, your ECU took a massive dump - ground traces shorted out.

 

[Coolhawk00]

ok i'll look into that

 

[DSM1G90]

I forgot to mention that when doing sensor changeouts, it's best to disconnect the battery for when a new sensor either gets disconnected or reconnected, it can cause a short to happen in the ECU since you have a constant 5v running through the sensors. And if any of that 5v touches ground or anything, it blows out the ground traces in the ECU.

Why I'm explaning this to you is that I went through the exact same thing, only with a coolant sensor that was giving me a CEL light and one of the wires attached to the sensor touched the block and suddenly, all of the codes associated to my sensors flaired up along with hard starts and running rich when I started the car with starter fluid.

I had to get a replacement ECU to cure my issue. Expensive lesson to learn but know we all know better.

Good luck-DSM