Hacking the DataStream

[RobertISaar]

OLDPA3 (decoded: previous pulse accumulator #3) = knock counter.

and you can always use just the LSB of the spark advance, it's a signed(or is it 2's compliment?) value, so unless you get near firing ATDC often, i wouldn't think its an issue. when bit 7 of the MSB is set, then the SA is displayed in ATDC, with FFFF being 0* or 0.39* ATDC and lower numbers being even further after TDC.

and yeah, once you have control of the datastream, you'll wonder why GM put in some of the stuff that they did.




also, RBob would probably know the actual BPW location in a 7747, no?

[EagleMark]

OLDPA3 (decoded: previous pulse accumulator #3) = knock counter.

and you can always use just the LSB of the spark advance, it's a signed(or is it 2's compliment?) value, so unless you get near firing ATDC often, i wouldn't think its an issue. when bit 7 of the MSB is set, then the SA is displayed in ATDC, with FFFF being 0* or 0.39* ATDC and lower numbers being even further after TDC.

and yeah, once you have control of the datastream, you'll wonder why GM put in some of the stuff that they did.

Thanks Robert I'll look into that when I work on this. Spark advance would be a good feature in ADX but with the XDF and ADX I set up data tracing so I actually know where spark is. It's not a requirment. Injector Duty Cycle/BPW Duty Cyle is not something I can data trace except back to VE to get an idea...

also, RBob would probably know the actual BPW location in a 7747, no?

His knowledge is amazing. He probably knows location from memory... if we fail I'll ask and I'm sure he would help as always. But right now I'm learning so much I just want to run with it for awhile.