Tricked-Out-Toy

iTrader: (1)

Im currently running a stock 97 lt1 and would like to try my hand a modifiing the PCM. Back when I had the TPI I did all the prom burning and wasnt very good at it. but I would like to try again on this setup seeing how its mostly stock and running great, the TPI was messed up too big of a cam not enough vacuum but thats another story. my question is what else if anything is out there?? and cheap! I looked in the LT1 edit software and it looked great but it was way to much and could only use it on one car. thanks for the help - TOT

Dave_Jones

No easy answer for OBDII, that I know of.

There is an OBDII version of TunerCat available now, but it's not what I consider cheap. I'd still pick it over LT1 Edit though, since it's not locked to a single VIN. And, if you don't already have an OBDII scantool of some sort, you'll need to spend another $150-250 so as to be able to see the results of your tuning. (OBDII requires a much more complicated cable than OBDI, so it's not so easy to make your own)

So, I'd suggest you consider running the '94-'95 OBDI PCM instead. It's GM P/N 16188051, and will plug right into the harness in place of your OBDII box. Used '8051s can be had from salvage yards for about $50-75 if you hunt around. About the only change needed, is to make sure the knock sensor circuit resistance matches what the PCM is expecting, either by installing the appropriate OBDI knock sensor(s), or soldering the correct resistor in parallel so the PCM sees what it expects. (I didn't mention specific values, since it's different between the F-body and B/D/Y-body applications due to them having one vs. two knock sensors)

If you do the OBDI conversion, you can reprogram it with the regular version of TunerCat, and scan it with a normal MAX232 cable using either FreeScan, or TTS DataMaster. Mangus has promised that it won't be much longer before he has the scan engine of TunerPro RT updated to work with the '8051 as well.

One other thing, you might also consider making a bench harness for reprogramming the PCM. That's by far the safest way; if you rebop them "in car" like most people do, sooner or later you're likely to have a PCM lock up on you, which isn't much fun if you don't have a spare.

You should be able to find the details on everything I've mentioned via a google search or three. I apologize for not posting some links but I've got to leave for work right now!

Tricked-Out-Toy

iTrader: (1)

thanks for the info, I didnt know that you could use the OBD1 PCM. what are the advantages/disadvantages of switching from OBD2 to OBD1 other than cheaper editing software. Also will I still be able to read everything through the ALDL port with the OBD1 PCM? Thanks for the help - TOT