Ok Guys I have been looking for someone who can tell me about the ecm/pcm in my silverado (5.7L). I have suspected that the ecm was replaced so I checked the ecm numbers and prom numbers to make sure I have the right parts. (yes correct) The truck never ran right when I got it, but it does run good with the timing wire disconnected (smooth idle) because I had to set the timing. I turn off motor and reconnect the timing wire and it doesn't idle and it runs like crap. Is there a way I can verify that the ecm is good or bad or the prom. Because if Im correct as soon as the timing wire is connected that runs the ignition through the ecm??? Im stuck on this one, so I thought I would ask here and I hope someone can point me in the right direction. No engine codes present

What exactly is the truck? In 93 you could have 3 different PCM's IIRC, one for each trans option. Also what did you set your base timing too? Does the timing advance when you reconnect the wire? There are several variables involved with timing on that engine depending on when it was built in 93. Some have a seperate timing module and some don't. You need to narrow down what you have first and go from there.

I belive the timing does advance when the wire is connected. Because it shows to be at the top of the ballancer although it runs very rough, like it misses firing on some pistons, as it pops and struggles to stay running. I've tried two other ignition modules and checked the vin # to the correct PCM and is ok. I don't want to shell out for a new chip if that's not what the problem is. The top of the sticker on the ecm/pcm reads 16168625 BDJW and the lower sticker starts with 16186695 BDJW The Prom # is 6029 BDJW

I would be interested in knowing what the seperate timing module is

I would be interested in knowing what the seperate timing module is

Some had a seperate module that the knock sensor went to and that retarded the timing for spark knock.

Is the anti knock sensor on the side of the Block? Wondering if a code would or would not show if this was defective. Thankyou for giving me something else to check