Question about added parameters

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Pontisteve
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Question about added parameters

Post by Pontisteve » Wed Feb 17, 2016 4:26 pm

I have questions about how parameters are added. Let's pick on in particular as an example.

There is a parameter CANPHP (Canister Purge Hardware Present) that does not appear to be in the GUFx strategy. A parameter has been added called Z_VPRG, that is described as a canister purge test enable/disable. I assume all the Z_xxxx parameters are ones that have been added to the GUFx definitions, that did not exist. Another example would be the Stoich AFR parameter.

In Z_VPRG, enabled = 31784 (7C28 hex) and disabled = 1056 (0420 hex), or 28C7 and 2004 hex if it's read backwards.

What is the significance of these numbers? How were they added? Was this a factory on/off switch that just wasn't listed in the GUFB strategy doc, or what? I need a little better insight into how these were added, and what the numbers mean. Any help greatly appreciated.
If it's worth doing, it's probably not easy.

decipha

Re: Question about added parameters

Post by decipha » Wed Feb 17, 2016 5:10 pm

the hex number is the opcode, you simply rewrite the code to skip over the segments you want to bypass

the disassembly write up will make it all clear to you if you scoot down to the opcodes youll see what they are doing

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Pontisteve
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Posts: 76
Joined: Mon May 16, 2011 12:33 pm
Location: FL

Re: Question about added parameters

Post by Pontisteve » Thu Feb 18, 2016 3:47 am

MIchael, could you link me to the disassembly writeup please?

I tried using Tunercats disassembly tool, but was underwhelmed... or underskilled. Not sure which yet. LOL
If it's worth doing, it's probably not easy.

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