Hey guys, could someone try to school me on why I'm seeing such radical Idle stepper values and ISCV changes in this tune? On the left is the tune I'm looking at and on the right there are stock values. I've never messed with these tables and am curious what something like this would do. I don't see many tuners adjusting these values, but I've found one that does and here it is.



Anyone experimented with something like this? What TYPE of differences should I expect. I am interested. Oh btw, these are both 9417008 '03 ROMs.

 

lol, seriously... someone knows something...

 

zoinks... i have no clue.

 

lol... zoinks.

 

I don't know exactly how the ECU uses the tables but the different settings are supposed to tell the ECU how much air the let through the throttle body at idle I believe. Increasing the numbers means you want more air going in.

Why would someone want that? Maybe they're trying to idle lean, but the ECU still wants to keep the AFR at 14.7 so it injects more fuel. So you get in effect a 'stronger' idle that uses more gas. My guess is these settings were changed to tune idle for some cams.

I experimented with my car and forced it to run open loop at idle then tried to lean the AFR via the high-octane fuel table but the ECU sensed the leanness and increased the ISCstep on its own resulting in 14.7 AFR idle that uses more gas than before I made the changes.

 

Cool, thanks for the input. I figured it was for cams. I'll see how Idle changes.

 

the idle was much stronger w/ my cams this morning but it had a tendency to overshoot my idle target and idle somewhere around 1200. I'm going back to stock for now.