ok so my freind got a 1990 corvette and the guys said the computer was fried so we put a new ecu in it but it wont fire. we tryed to reset the security with this key method we found. any ideas

 

How did they decide the ECM was bad.
Does it crank?
Did you use noid lights to check for injector pulse?
Does it run a few seconds and stop?
Did you measure the pellet resistance and put an resister in to replace it in the harness?

 

the guy he got the car from said it was bad and had a new one just never put it in

 

Central timer modules (BCM) go bad in those too. Have to do some testing & see.
Those will get the security light going too.

 

90 vette should not have a BCM, they were TPI motors, that used a VATS module to operate the the anti-theft on the starter and the ECM

 

ok we started messing with it and it will it will turn over but wont start when u roll the windows down will turning the key. its not firing and the fuel pump wont turn on

 

is the correct prom chip in the computer?

 

yes it. but if it goes bad will it cuase it to do that

 

Did you check for pulses with noid lights on the injector plugs?

 

how do u do that. srry still trying to learn this crap.

 

Noid lights are little plastic plugs with an LED in them, that tells you if the injector is getting a fire pulse, when you plug them in to the injector plug. If you have a Harbour Freight near you, you should be able to buy a set for $20, if its a VATS issue there will be no injection pulse. Did you check the fuel pressure? We all have to learn sometime

 

yes it would but I can tell you I have NEVER seen one go bad just missing when ecms get swaped out.

 

"but wont start when u roll the windows down will turning the key."
Huh??????

 

ok it will only turn over when u hit the window button while u turn the key. but it still wont start.

we still cant figure it out

 

you condem the ECM, I'd be looking at some wiring diagrams, and see how there may be a connection to the power window circuit.
There's likely some interface that powers the window circuit only when the key is in the on position??
Windows work w/ key in run position?
Windows work w/ key off?
A trip to the Vette forum may be in order....