Hey guys,
I bought a new ecm- read up on service manual haynes..my 88 vette was diagnosed I needed a new ecm. Okay-I did everything right (uppp til the end) When completed I reconnected neg terminal and went to start the car.lights in console on, everything looked ok. Then when I turned the key, bam! The car was shot. no power, as if ...well...I think the worst. How can I find out or can I find out if I put the PROM in backwards? I thought (famous last words) I had it correct. But My guess is I blew up the Prom. If so would the car have zero everything? like a dead car? can you tell by looking at it if I blew it.

My biggest fear is did I blow or cause a major problem..I recconnected all the plugs properly I am sure of that. If its the prom is it expensive?

I'm starting to let my frustration get the better of me with my car. suddenly its not so fun anynore. I'm no mechanic but I can follow directions. until i know what damage i did I am so angry for trying myself. But i guess if you dont fall down at the beginning you can't learn. Please nobody crack on me...todays been hard enough

Thanks,
Ronnie

 

You would have to use obvious excessive force to reverse or cross plug in your ECM. You could provide us with a better description of, "no power". Do any dash lights come on, courtesy lights, starter motor crank the engine, headlights turn on? Measure the voltage across the battery posts and post the reading. Measure the voltage across the cigarette lighter plug. Almost all power to the car goes through the ignition switch and the ignition switch gets power through a fusible link connected to the jump start bolt behind the battery. Measure the voltage at the jump start bolt and post it. Check the 10 amp gages fuse with an ohmeter, the ECM gets power through that fuse and also through a fusible link likewise connected to the jump start bolt behind the battery. Remove the battery cables (neg first) and clean the cable lugs, bolts, and battery posts and replace the cables (neg last). A poor cable connection to the battery can cause your symptoms. The ECM costs about $120 to replace (bought one a long time ago, so price is approximate).

 

I'm willing to bet it's just a loose/dirty battery cable like jfb said. Check them first of all.

 

I didn't attack the battery tight enough, but bad new is, (my diagnosis, what do you think- my alternator i replaced before the ecm- when i kept gettting the battery surges, i believe i blew the new alternator. basicly the car is not keeping the charge. battery brand new optima 1. What are signs of the distributor is on its last leg? There is a loud clicking noise!

If the ecm is good, and the Prom is bad or wrong one for the car, would it make the data reading from the obd1 "Not available"

I read that 1991 and up have the prom with the 2 buttons on the side that ypu push to get the prom out. on 91 and below, you need a special tool. the prom in my 88 is the same as 1 found in 91.

the previous owner really did me wrong, but worse- he couldn't or wouldn't replace parts on the car with the correct ones-

thanks

Ronnie

HOPE THE HOLIDAY WAS GREAT- awesome weekend for a corvette road trip-

 

Just replaced the computer in my 90. 2 buttons that you push up to remove the prom.