GM 16216588 - Hacking

[quadstar87]

Antus, you are a machine!

Ohh look....the base fuel quantity table. It's the same dimension and shape as the OBDI as I expected.

Hundreds and hundreds of tables on the wall...hundreds and hundreds of tables...map a fuel one...take it down...hundreds and hundreds of tables on the wall

base_fuel_obd2.JPG (81.16 KiB) Viewed 6641 times

[antus]

Haha hundreds and hundreds of tables on the wall. That song is going to be going through my head all day now.

[quadstar87]

Haha hundreds and hundreds of tables on the wall. That song is going to be going through my head all day now.

You are welcome! Have a TimTam and all your worries will go away

[quadstar87]

Found base injection timing table. Man this is FUN once the data isn't scrambled. They used the same structure for the important tables so I can just use 2D/3D viewers to find what I need.

The nice thing with diesels is that there is no VE, AFR, KNOCK, etc in these old PCMs. You just inject more fuel and give it more advance and you make more POWA! Well there's more to it but...you can do some damage tuning these and only mess with 4 or 5 tables. I'm hoping the trans line pressure and shift tables are similar too.

It's also really interesting to see that GM actually gave these a good bit more fuel and timing advance in the OBD2 PCM's. I'm thinking they implemented some tables that weren't used in the OBD-I like MAP referenced fuel de-rate because this would smoke a good bit as-is if it was only using the base tables and no modifiers.

OBD2_TIMING.JPG (59.6 KiB) Viewed 6620 times

Now to figure out the segment(s) and checksums so stuff can actually be changed and new BIN/CAL created.

[quadstar87]

Halt

Can anyone tell me why i'm finding duplicates of tables. For example, the 17x17 3D @ 0x2BE6 is also @ 0x12BE6

[antus]

Could be a bad read or could be intentional cheating at bank swapping (swapping more than they need to). Or since they swapped address pins this could also be there to confuse you. I suspect this is the most likely. So i'd ignore 10000->17FFF. In our 128k pcms 0->7FFF is always mapped low and 8000->FFFF and 18FFFF->1FFFF are toggled in to the 8000->FFFF range so the HC11 can see it so that you get a common low bank with the calibration data always present and a seperate pair of 32k high banks . One contains engine code and one with trans code. 10000->17FFF is never swapped in and is not used.

[Charlescrown]

Because it's a diesel you will find a fuel (otherwise known as drivers wish map) and smoke map for each gear I don't know why they do it but I bet that's the reason so many maps. You will also find maps for the start and finish of injection that may also be for each gear. My Hyundai list over 200 maps using winols. Some obviously not really maps but there are sure plenty to play with.

[quadstar87]

Could be a bad read or could be intentional cheating at bank swapping (swapping more than they need to). Or since they swapped address pins this could also be there to confuse you. I suspect this is the most likely. So i'd ignore 10000->17FFF. In our 128k pcms 0->7FFF is always mapped low and 8000->FFFF and 18FFFF->1FFFF are toggled in to the 8000->FFFF range so the HC11 can see it so that you get a common low bank with the calibration data always present and a seperate pair of 32k high banks . One contains engine code and one with trans code. 10000->17FFF is never swapped in and is not used.

Antus, How does this relate back to this information and any tips on how I should split the re-addressed BIN up to pass into a HC11 disassembler?

"There's space for two 32k memory pages (bank swapped using pin PG3) and one 24k
non-banked page shared between calibration and common (non-banked) code."

[antus]

Grab the bottom 64k and call it bank 1, and split off the bottom 32k and add 18000-1ffff and call that bank 2.

[vlad01]

Because it's a diesel you will find a fuel (otherwise known as drivers wish map) and smoke map for each gear I don't know why they do it but I bet that's the reason so many maps. You will also find maps for the start and finish of injection that may also be for each gear. My Hyundai list over 200 maps using winols. Some obviously not really maps but there are sure plenty to play with.

lol great descriptions. wish map and smoke map