What the heck is a Prom? Is it the computer?


{edit: changed one word, mod}

 

PROM is the acronym for Programmable Read Only Memory, or, the chip that holds the calibration data. Yes, in the computer, sometimes called the ECM.

By changing the values within the PROM a user is able to change the tune of the engine. Items such as spark advance, AFR, TCC lockup points can all be updated (among others).

RBob.

 

So my carburated car doesn't have this. I've got a distributor right? Thanks for the info!

 

If your car is a stock US based model then yes it has an ECM. The carb will be a computer controlled carburetor (CCC) and the distributor will also be under ECM control. Same with the TCC, EGR, and AIR. If it is still factory stock.

At key on, engine off, is there a clicking coming from the carb? If so then a sure sign it is a CCC model.

RBob.

 

Hmm. Well, my car has a different carb and distributor on it. I don't ever recall her clicking when the key is in the "on" position, but maybe it does. I'll check it out next time! Thanks

 

Yes, very possible. Many 3rd gens have had items swapped out on them. Which is why I stated 'stock US based model.' If it doesn't have the factory stuff, and US emissions isn't in the cards, then just keep it in good tune and enjoy it.

RBob.