So, in my 89 GTA that came with a 5.7L originally, I now have an 88 5.7L from another GTA. It was replaced years ago and was there when i bought the car. Trying to get it tuned up and kept struggling with timing. If I set it at 6 or 8 deg, it doesn’t run well at all and pings pretty bad. I timed it by ear and it’s roughly 15 degrees off. Brought #1 up on TDC and it is not 180 degrees off. Runs and drives good and has good power but the timing is way off of the marks. Not running lean or rich and seems fine, just nowhere near the timing marks. Is there a problem with the 88 motor working with the 89 computer? The 9th injector is disconnected but everything else is connected from what I can see. I did unplug the timing control plug back at the firewall when I timed it. I took it to a shop to have them look at it and they also timed it and found the same thing. They guessed maybe the computer? THey also replaced the balancer in case the old balancer slipped. Same thing. Thoughts? It’s running and driving good now but I am confused as to why the timing would be that far off. - Thanks!

 

Its not the ecm as long as chip is same. But i guess ecms can go bad so theres always that chance

I would have guessed slipped balancer

When you bring it to tdc on 1, what timing does the balancer say its at? Might need some balancer tape to get more degrees to read it. But that would give you an idea