IgorT.455/406

Hey guys,

I am considering getting a '97 LT1 auto car, it has low miles (35k), but some mods. It has a cam, headers, suspention, fipk and who knows what else. Car runs good.

My questions are regarding the obdII system. I am used to my '94, and, have tuned it with tunercat before. But its been a couple of years since I had my '94, so I've been "out of the loop" so to say. Is there anything new for obdII cars to make them easily tunable? And if not, to convert the thing to OBDI, what parts would i need (I have a complete '94 parts car).

My question is, with the obdII cars, what software can be used (if any now), to tune the cars? What about using O2 syms to get rid of the cats, etc. I am just looking at the main differences between the '94 and '97 that could come up with trying to swap parts, etc. I still have ALL the aftermarket parts in my sig from the '94, as well as the '94 itself as a parts car. It was in a collision where it got written off, and now sits in my shed as a parts car.

Thanks guys.

truedualws6

If you are already familiar with OBDI then just get a conversion PCM
tuned for your car. Find out what cam is in it so you can tell the tuner.
A little cheaper way to go is to buy PCM off the board and then change
the knock sensor to the 94-95 style.

IgorT.455/406

Thanks.

I already have a pcm myself, I was not aware of the conversion pcm. I thought it would involve changing the wiring harness to the obd1 as well.

Thanks.

truedualws6

Since you already have an OBDI PCM then all you need is to have it tuned
so that it works with a 97. The knock sensor is the only physical change
necessary, all the rest is programming. I am running OBDI in my 97 with the
94-95 knock sensor and it runs great. It should run better than OBDII.

Dave '97 Z28 M6

Tunercat now has an OBDII version... but it's something like $400, and still not listed on their website, to my knowledge.

Both http://www.pcmforless.com/ and http://www.madz28.com/ sell OBDI conversion PCMs (custom programmed) for reasonable $$. They are totally plug-and-play, set up for the car, and require no modifications to the wiring harness or anything else whatsoever - I have one in my car. You could send them your spare OBDI PCM and get a few bucks off the regular price.

With an OBDI conversion, all your existing software would work, but you'd need a new cable, since your car would be essentially similar to a '95 (OBDI PCM with an OBDII-style connector). I'd suggest http://www.akmcables.com/

An OBDI conversion PCM would just ignore the rear O2 sensors (so you could delete the cats without getting an SES). Obviously you don't have to deal with a sniffer test like we do here in SW Ontario.

A couple of advantages to staying with OBDII: 1) Some guys have problems with the OBDI PCM working well with a high-stall torque converter - being an M6 guy I don't know much about that. 2) The OBDI PCM cannot run an engine over 7000RPM, whereas the OBDII limit is much higher.