....and what does it do?

I'm going to a pull-a-part tomorrow to ****** an ECM. I saw on the "enterchange page" that they are "less prom".

Is this something I need to know, or will any ECM with the correct numbers work?

Thanks

 

Prom, a formal social gathering near the end of Highschool....hehe j/k

P.R.O.M.= Programable Read Only Memory. It contains the info the ECM needs to operate the engine correctly.

As long as you get the correct ECM for your application (ie 870, 165, 730, 749 etc) and get the correct memcal (calpack) for your application ( V8, V6, L4, TPI/TBI etc) you'll be good.

 

prom stands for (programed read only memory).
the prom is a chip set inside the ecm there is a acces door held in to place by two small screws on back of ecm.

 

Here's what you need to do when you have both ECM's sitting side by side on either a workbench or table:
1. Remove PROM cover screws.
2. Remove PROM from the ECM that was pulled from YOUR car.
3. Remove PROM from the J/Y ECM and switch it with YOUR PROM.
4. Set J/Y PROM in a safe place, away from any light and moisture, in an anti-static bag, where you know where it is, so if you need it, you have it.
5. Replace covers on both ECM's.
6. Install your "new" ECM in your car.

Why? Because, unless the original PROM is corrupted in some way, it is necessary to keep the original PROM with your engine. This is because the BLM tables in each PROM are slightly different for each engine from the factory, whether the PROM has been modified or not, due to slight differences between engines.

 

Thanks for the info, all!

They only had one car there with my specific box(1228746)...a 1990 Caprice.

Yep...different PROM. Swapped those out and all has returned to how it was screwing up BEFORE I toasted the ECM!

I suppose I must have a fuel delivery problem. Trouble is, it only shows up once the car is warm and driven.....and no codes(well..except 44 after it decides to act a fool!)

I'm hopeing for injector troubles but mentally preping myself for fuel pump.

Once again, thanks folks!