tricking a M6 PCM into thinking its in Park??

[MrDude_1]

ok, i have this idea, similar to what some other cars have done.
i want a 2step on this car..

right now, my PCM always thinks its in 4th gear..

i need a way to make it think its in park/nutural... if i can do that, i can set the park RPM limiter to launch RPM, and use it like a 2 step.

ideas?

[chrisj6]

Are you talking about keeping the idle speed the same in both park/neutral and drive? Just keep all the idle values the same.


Chris

[horist]

when the clutch is engaged does it think it's in park then? or still thinks it's in 4th?

I bet there's a pin on the PCM that the A4s use to set a park/neutral signal ... if it's not the same as the clutch signal then you could prolly tap into that... I'll try to find the wiring diagrams for our PCMs in a bit

[MrDude_1]

when the clutch is engaged does it think it's in park then? or still thinks it's in 4th?

I bet there's a pin on the PCM that the A4s use to set a park/neutral signal ... if it's not the same as the clutch signal then you could prolly tap into that... I'll try to find the wiring diagrams for our PCMs in a bit

if you could, that'd be great...

i tried grounding the pin 32 on the blue connector... ( gray wire.. suppost to be clutch pedal position switch)..

i was watching HPtuners and it still showed it as 4th gear... i datalogged driving around, it never changes.. the PCM ALWAYS thinks its in 4th.. or atleast thats what it reports.

Are you talking about keeping the idle speed the same in both park/neutral and drive? Just keep all the idle values the same.


Chris

no.
in the fuel cutoff (rev limiter) you can specify it by gear.
heres the idea:

normal driving: PCM assumes its in 4th, just like normal. rev limiter is 6200

when i push the "2 step" button, the PCM assumes its in park... looks at the other field in the table, and holds the RPM at 3000.... and it stays steady at 300 until i launch the car.... on the full uptravel of the clutch pedal, i'll have it hit a microswitch, instantly making the computer think its back in 4th, and the limiter is 6200 again..


the goal is more consistant launch RPMs.

[chrisj6]

Gotcha.

Chris

[MrDude_1]

ttt.
i cant seem to figure out how... ideas?

[horist]

Here's the PCM pin-out
http://www.ls2.com/forums/showthread...threadid=19273

[MrDude_1]

thanks...


hey, on pin 34 of the blue connector... the "Neutral Safety Switch Signal"... does that goto ground or what? i dont have a GM manual for a 4thgen, or id look it up myself.