Hey,

I'm looking for any knowledge or information anybody is willing to share on these PCM's (or ECMS whatever). I have a 1991 GMC rally wagon van that I believe needs an engine computer. It has an error code for "ECM Prom error". My van has the ECM with the brown connectors below. Here are a few questions I have;

Is that black thing in the picture considered the prom chip?

What years / vehicles used this ECM with the brown connectors?

Does anybody know a part number or technical identifier for the ECM with brown connectors?

Some "throttle body injection" wizard I met at the junkyard told me that guys swap the red/blue computers into vans because the van will perform better. Does anybody have a thread they can point me to / any information on swapping the red/blue computer into my van?

Is that white box in the picture with the red/blue computer considered a prom chip too?

Thanks everybody!


If you're interested in the back story I think that I fried the computer jump starting the van. I had a battery charger and a car jumping a totally shot battery, my bad. It cranks but won't start, it has a new battery now and an active error code for PCM prom error.

 

PROM stands for programmable read-only memory . It's where the various engine parameters are stored (fuel mixture etc.). It consists of a chip (or several chips) and they're on a circuit board inside that box you're holding. The whole box is the PCM/ECM and contains various control circuitry and processors.

ECM stands for Engine Control Module. When the transmission controller and engine controller are together in one unit they call it a Powertrain Control Module (PCM).

Anyway bottom line is grab a brain box from a same year junkyard van. It might have to be programmed to your VIN first.
Part numbers can be obtained from rockauto.com