TBI computer help.. 454ss truck

[sasquatch094]

When i bought the truck, the original owner threw a cam and a few other goodies on the motor. He passed away and the motor was slightly torn apart. I put it all back together got it running and it would never run "good" even at idle. The SES light was blinking rapidly and it had some ****ty Jet chip in it. Decided to take it to the local speed shop to have it tuned on the Dyno and get a custom chip made up (towed it there dec 8th). Its still there as of today and no good news. They told me the computer was shot, so they went out and got a refurbished computer and new prom. They said as soon as they put in the prom, it shorted out or blew up. Making the ses light come back on.

Im pretty fed up with this company by now and will shortly pick it up whether its done or not. The truck has an aftermarket cd player and security system on it. Can anyone help me out faster then the shop can?
1990 chevy 454ss 7.4liter..
Mods include:
k&n open element
TB spacer/injector spacer
march underdrives
edel shorties,3" y, 3"dual exhaust from there back
edel TBI intake
Edel 2162 cam
taylor 8mm wires, cap and rotor

I set the timing at stock base which was 4degrees i think? Any help would be GREATLY appreciated.. i have a few videos of it running if that helps anyone..

[sasquatch094]

More updates.

set the truck timing at 6 degrees, runs good, then jumps to 12 degrees by itself runs like crap then jumps back to 6degress..

Anyhelp??

[randeez]

base timing should be set at 0*, all the advance/retard comes from the ecm...if there really is something "shorting out" the ecm i would look into correcting that before anything. i dont know to much about the 454s but i imagine with, for the most part, just a cam it should still run decent on the stock tune