I am in need of a new PROM for my 350 swap into my Jeep. I had a couple of questions:

1) Why cant I just use the PROM that came in my ECM?

2) What do I need to know to tell the person I choose to do my PROM?

3) Who burns good PROMs?

4) Does someone on here have a good burn from someone that I could have copied?

J. J.

J.J.

Its me again!

You can't use the PROM that was in your ECM because it is set up for the car it was in and the cam specs of the car it was in. Also when doing a custom swap you need to have the VATS disabled (thats the anti theft system) the EGR system, the the speed sensor. Without a PROM with these things disabled your ECM will keep thowing codes.

You need to tell the person that burns your PROM everything about the engine as possible.

Cubic inch
injector size
Cam specs
compression ratio (if your over 9.8:1 expect a little trial and error)
exhaust type
fuel pump pressure
estimated HP
type of distributor
gear ratio (if you have a speed sensor)
temp you want your electric fans to come on and off
If you have your EGR hooked up
where you want the rev limiter set at
idle speed

One thing I did was had them hook up the A/C circuit so when I flipped the switch the engine would rev up from 700 to 950 and sorta had a cruise for the trail.

It is very hard to copy a burn because there are so may variables to work with, basically the PROM will be tailored to your engine. If you decide to change your cam in 2 months plan on a reburn.

I had www.jimsperformance.com do mine.

I have heard good things about these two guys also, bounce your setup off of them and see which one sound most willing to work with you.

http://www.eidnet.org/local/westers_garage/ His name is Lyndon
http://www.customefis.com/ this guy is John Wilson.

Hope this helps and good luck....

Mark

What if I don't know about my cam?

J. J.

Perect, thanks for the links, just what i was looking for on my 4.3 swap..

Originally posted by patooyee
What if I don't know about my cam?

J. J.

Ummm.... that is just about the most important bit of information they work off of.... I would get in contact with some of these guys and tell them what you "think" you have. If you are able to get it to start and hold an idle you could pull vaccum and that MAY help them get going in the right direction.

http://www.thirdgen.org/newdesign/tech/promintro.shtml here is a good article if you wanna do it yourself

I can't remember what ECM you'll be running (.....TBI or TPI, or whatever). But with my 350 TBI, running the 1227747 ECM I used a stock chip. No VATS on these early computers.

Works fine for me.

I'm also running a Comp cam (206/212, 425/440).