OBD2 LT1 XDF $EE EEX creation

[Tom H]

it'd be nice to find the parameters so you could widen the angle that it considers a misfire and still retain some misfire detection, but other tools don't have that so people tend to just disable the error code so their dash doesn't blink at them. also the misfire detection doesn't SEEM to do anything other than flash the light, but nobody is 100% sure about that

I am sure (?) I can find it, once past these programming routines I will take a look. You are talking about the dtc.. right? There is a table where each dtc can be disabled/enabled. I sort of remember that there are four classes. I will refresh and post back later.

Somewhere in the last 25yrs I was told by someone (sort of vague?) that misfire was done by looking at the time between hi-res ticks. If she fires, the momentary acceleration of the crank would reduce time to the next tick. That & the
operation of the crank sensor beyond looking for the disable is probably a fall task. That is unless we all get locked down.
Easy to see how a lumpy cam would mess with all the crank acceleration stuff also.

-Tom

[steveo]

i dont know if the DTC is separate from the misfire detection code flashing the check engine light...it does both

[Tom H]

i dont know if the DTC is separate from the misfire detection code flashing the check engine light...it does both

If your car is like the 96/7 Camaro/Firebird, I can give you a suggestion in a few days that *should* stop the lights. Can you tell me what code it is throwing??

[steveo]

i don't have a car
from memory it sets that obd-ii code called random misfire

[kur4o]

More comments added.

[sherlock9c1]

Well, I've got the disassembler open and am looking at the OBD1 code, with a whole lot of help from kur4o. And great work him on the commenting! I need to start an Ibuprofen fund; whew this is new territory for me.

[In-Tech]

More comments added.

Hi kur4o,
My version of ida is so old I cannot view your work. Could I talk you into saving/produce as html so I could view it? My old version of ida used to be able to do that with a keystoke.

[kur4o]

Hi kur4o,
My version of ida is so old I cannot view your work. Could I talk you into saving/produce as html so I could view it? My old version of ida used to be able to do that with a keystoke.

You can check here for a way to open the files or

if you are still having troubles here are some htmls. There is options to export to other formats but don`t what they are.


I managed to find that there are 2 revisions for the 96-97 files[1 for 96 and 1 for 97]. This is valid only for the latest updates by gm so any older p/n for the vin might have different layout.

I am looking for stock bins to confirm there isn`t any older revisions.


For now at least 2 xdfs will be needed.


We can transfer the thread`s topic to xdf and flash creations and we will be spot on with the conversation without spamming the thread.

I hope sherlock9c1 doesn`t mind.