Getting ready to swap out to a OBD1 PCM on my 96 motor, should I worry about cylinder balances being different in the two pcms? I don't have anything to read the OBD2 programming to see what it's set to, besides the heads have been changed out from iron to aluminum. Short of getting an EGT setup, what options do I have?

Thanks,

Jeff

 

ttt, anyone?

 

If the 2 PCMs were for the same engine, the cylinder balance needs would be the same regardless of whether the PCM was OBDI or II. Unless your OBDII PCM has modified balance #'s, you should be OK.

Now, would the head swap require different balancing? I don't know. I would think that it's more to do with the intake manifold than anything else, and that is unchanged, right?

Just tryin' to help, since you weren't getting any responses.

 

Thanks I do appreciate it. I have a number of downloaded tunes I need to look through to see if there was a general # gm stuck w/ for the balance #s or they custom programmed each pcm for each motor. (Also curious if the mail order guys are paying attention to that area)

I know those #s are pretty much used as fudge factors to keep each cylinder... lol, balanced as far as fuel delivery goes, just wondering what i can do to get them back into spec. this motor is a mish mosh of parts, it's a 96 caddy block w/ 97 camaro ss aluminum heads, heads were rebuilt, think they might have been mildly ported, stock intake, stock injectors, stock manifolds (maybe switching out to shorties), etc etc.

saw where one guy was taking a laser temp gun and measuring his primaries, which is in a way useable data. I might just set all the balances to 1 if i don't figure anything else out and let it ride.

Thanks again for the reply, I appreciate it.

 

Well, I read here that GM didn't program anything other than 1's in the off-idle cylinder balance tables until '95.

Since you've been a customer of pcmforless, I'd suggest e-mailing Bryan and Alvin about this. They could probably give you a quick answer. Or PM Alvin - I've seen him on this board quite a bit.

Like I said, I think the balance has more to do with the intake manifold's peculiarities than anything else (although, obviously, there's a lot of other factors i.e. headers, heads, etc.).