sorry . im still new to engine repair. what exactly is PROM?

 

PROM - Programmable Read Only Memory. Most people call this the "chip". For your car (89), the "chip" is soldered onto a Memcal that contains circuitry for the ESC (Electronic Spark Control).

Most people don't actually use "PROMs", but eproms or Flash Proms. The main difference is that eproms and Flash Proms can be reprogrammed while a Prom cannot. The "chip" on the stock GM Memcal is an eprom where you erase it by UV light and then reprogram it with a programmer (or "burner").

Check out Tim Sifford's (aka Traxion) article on Prom Burning. This is what this board is primarily about - burning proms for your own usage. You cannot "buy" an eprom that is better than you can burn yourself - something many of us have learnt the hard way.

For more info, go here

https://www.thirdgen.org/newdesign/tech/promintro.shtml

 

but what exactly does it do for your car?

 

Do you mean "What does a chip do for the car"? Simple, it makes it perform better. Even on a bone-stock engine, you can see increased performance, better driveability, lower emissions and better gas mileage.

Your car is Speed Density and more sensitive to engine modifications. To get the engine to perform optimally, you almost always need to get a new eprom.

But don't waste your time on those "over-the-counter" eproms because they are complete junk. And, many of the "custom eproms" from "custom tuners" are often not much better.

The BEST WAY to obtain an optimal eprom is to do it "hands on and yourself". It can take a lot of "tweaking", but it is not hard work. Unfortunately, if you had to pay someone to "tweak" each chip to see which performed better, you will quickly rack up one hell of a bill.

That is why most guys who want the most from their engine burn their own eproms - because most of us have been "burned" by these "custom tuners" ourselves, and realize that the only way to do it, is yourself.

 

The only thing I have to add is that the EPROM contains all the information that is necessary to allow the engine to operate. The EPROM is like the brain. The only reason I added this is because you said you are new to this and maybe you didn't already know it.

Definately, learn to tune your own chips. Just for comparison, you can get most of the equipment necessary to tune EPROMs for less than or equal to what ONE aftermarket "performance" chip would cost. Then you can tune as many chips as you want, once you get the hang of it, you will be making changes often. The only part that may get expensive is if you decide to use a laptop to run a scanner program to data from the ECM. You don't have to use a laptop based scanner so there are other methods. Good luck.

 

Not to mention that once you understand how the engine works on such a highly technical level, you'll be able to diagnose problems a heck of a lot easier. With a scanner in hand, you'll be more able to determine whether an off-idle stumble is ignition related or fuel-delivery related (though many of us still have those super-mysterious problems occuring which forces us to write the hysterical HELLLLLLLLLP-type posts ) )