Background:
Running a 94 B-Body Roadmaster LT1 (in a Mazda RX7). As part of the build, I put together a custom CAI to fit around the various obstacles I have, and had to add electrical tape to the MAF to get it to fit 3.5" intake couplers (which I thought was odd at the time...). Drove fine, until the tape got hot, slid and covered about 1/4" around the inside of the MAF, restricting airflow enough to make a noticeable SOTP difference. As part of fixing that, I stumbled across the fact that the B-body MAF is 3.25", but everything else is 3.5". Having felt the noticeable increase in HP from a tape-restricted 3.25 to unrestricted 3.25, I want to go the next step to the 3.5" off the F-body.

So... (Here's where you all start yelling at me) I picked up a ported/descreened f-body MAF on the cheap (yeah, I know, don't do a ported MAF, it messes with fuel tables, etc). My justification, however, is that since I was already going from 3.25" to 3.5" (from roughly 8.3 in2 to 9.6 in2, or about 15% increase in area) I figured a recalibration is in order anyhow.. so might as well do a ported/descreened since the programming involved is likely the same. That's my justification, anyhow, and I'm sticking to it!

So, after initial swap, the car idles fine, but sounds a bit.. lumpier. I can't get moving without it trying to stall, and it's very rough up to mid-rpm range then smooths out. Eventually (10+minutes) it will sort itself out enough to be relatively driveable (and the idle becomes noticeably smoother as well), but I still feel a tip-in stumble and everytime I drive the car the learning process has to start over. So it needs to be reprogrammed (was honestly hoping it was going to learn on it's own.. oh well).

So, how does a guy go about recalibrating? I am using the standard 94 B-body PCM, programming via TunerCATS and logging via EFIlive V4. I've tried doing searches but am not finding the answer... any help appreciated!

Wallyman

 

If you had gone with an unmolested f-body sensor it would have been easy as copying the tables from a f-body program.

What you are looking at now is building tables from scratch.

Might log with the stock b-body sensor under a variety of conditions, the replicate those conditions with the new sensor and program it to read the same. Will get you started but you are in for a LOT of trial and error and in the end it would be easier to just get a sensor not hacked up and that wont cost you any power.

 

I can still do that, however, where do I find an unmolested F-body PCM progam and what tabes/values/constants am I taking from it?

Wallyman