Soma07

Anyone? I'm working on something and it would really help if I had one to look at.

It has to be from a 93 M6 car with the M28 "wide ratio" trans option with 2.73's. I already have the M29 .bin and I would like the M28 for comparison purposes. I realize they were pretty rare but it never hurts to ask

If anyone has it post a URL or you can email it to me, soma0007@yahoo.com.

Thanks!

Wilson

Jason,

I might have that one. What's the code for that Memcal?

Soma07

Wilson,

I have no idea. Do you know how I could find out?

I can tell you its not "BDLD" though. Thats what my stock M29 memcal has on it.

Thanks for the reply!

Wilson

Here's what I was able to dig up from my old archives.

BDZL superseded by BNXF which are for an F body 5.7 "P" with 4L60, 3.23 axle. GM pt #16216379
BNXD F body 5.7 "P" with 4L60, 2.73 axle. GM pt #16216377
BPBD F body 5.7 "P" with 4L60, 2.73 axle. GM pt #16216990 (different MPH cut-off for speed rated tires)
BDLD F body 5.7 "P" with 6 SPD, ??? axle. GM pt #16216819 No axle ratio specified, probably only one available with 6 SPD.


From what I have seen, all M6's might use the same BDLD chip. Because our ECM dont control the tach or speedo. So I dont think their is a difference from the 3.23 chip vs the 2.73 chip. But thats just me. Can anyone else confirm this?

Soma07

Thanks Wilson!

What im trying to do is figure out a way to recalibrate the speedo without a recalibration box.

By looking at the 93 Factory service manual I can see the speedo is controled by the ECM (at least to some degree). Basically the ECM takes the signal from the VSS sensor, proccess it somehow, then it provides a 4000 pulse per mile signal to both the speedo and the cruise control module.

Now in Tunercat there are two parameters which look like they should affect the speedo, the road speed contstant and the instrument panel VSS pulse divisor. I've tried varying the road speed constant by +/- 30% and the speedo appears to read the same so that doesnt help. However if I change the instrument panel VSS pulse divisor I can get the speedo to read ~30% faster than it should. Only problem is I can't do it with any kind of precision. The stock value is 98 and I've tried both higher and lower values but they both skew the readings the same way (up).

I was hoping if I could find the values for those two attributes that GM used on the M28 cars I could figure out how they compensated for the different gear ratios. But if both the 2.73 and 3.23 M6 cars use the same MEMCAL then the key lies elsewhere, not in the ECM (possibly in the VSS sensor itself).

Thanks again!

Edit: There is at least one guy on the board with a 93 M6 who has had Ed recalibrate his speedo via programing so I'm pretty sure this is possible. I just need to figure out how he did it. However there is the possibliity that I am missing a variable that Tunercat doesnt know about.