Computer problem with 95 prizm

[mrpackrat]

Hello all, I have a puzzling problem with a 95 prizm with a 5 speed. Ok, I just bought this car-not running. The story goes that the alternator caught on fire and melted the wiring harness from the alternator to the top of the valve cover. Nothing else. The alternator was replaced with a rebuilt and the wiring harness was spliced fron the middle of the valve cover down to the alternator(real good job too). Well here is the problem. When these parts were replaced the car never ran again, and it will crank over, but when you turn the key to the off position, the temp gauge pegs out-hot and the check engine light glows-this is with the key out of the ignition....The mechanic that did the alternator and wiring guessed that the computer was bad from the fire. Good guess, but not the case. I got another computer from the same year and tranny(exact same numbers on the computer),and it does the exact same thing. I got another computer from one year off with differnet numbers and it does not do the same thing, but it also will not start. Oh yesw another weird thing is that if you disconnect the injectors the check engine light and the temp gauge act normal-but of course it will not start either.... Any ideas???? Thanks