Idle tuning, SD, and A/C torque
Idle tuning, SD, and A/C torque In the middle of.... still.... VE table tuning.
After tweaking VE, tweaking MAF, starting over, tweaking VE.......
My idle isn't right anymore.
The problem: Floating idle on decelleration. (clutch in, 0% throttle, cruising or braking to come to a stop). It's been a reaccuring problem ever since Heads/cam was in, not a new problem.
What I've done: Tweaked RAF, tweaked throttle cracker, tweaked IAC vs. effective table (a long time ago), now I put that table back to stock.
The floating idle is worse with A/C on. So, I've set the "AC tq vs. AC pressure" table to 85% of stock. I think it's gotten a little better. Is that the right table? (I can't find any info on it). Also, what do I log to see when the AC tq table is correct? Ideally, should the STIT and LTIT be close to the same with AC on and off?
Another question. Everyone says to tune idle, then tune VE. But, changing my VE table changed my idle. So, I'm kinda tuning both right now (idle and VE). I'll finish with VE once idle is better. Is that correct?
Also, I'm doing my idle tuning with MAF unplugged. Will that change everything after recalibrating the MAF? (I can't recal MAF till VE is right, and I can't get VE right until idle tuning is done).
After tweaking VE, tweaking MAF, starting over, tweaking VE.......
My idle isn't right anymore.
The problem: Floating idle on decelleration. (clutch in, 0% throttle, cruising or braking to come to a stop). It's been a reaccuring problem ever since Heads/cam was in, not a new problem.
What I've done: Tweaked RAF, tweaked throttle cracker, tweaked IAC vs. effective table (a long time ago), now I put that table back to stock.
The floating idle is worse with A/C on. So, I've set the "AC tq vs. AC pressure" table to 85% of stock. I think it's gotten a little better. Is that the right table? (I can't find any info on it). Also, what do I log to see when the AC tq table is correct? Ideally, should the STIT and LTIT be close to the same with AC on and off?
Another question. Everyone says to tune idle, then tune VE. But, changing my VE table changed my idle. So, I'm kinda tuning both right now (idle and VE). I'll finish with VE once idle is better. Is that correct?
Also, I'm doing my idle tuning with MAF unplugged. Will that change everything after recalibrating the MAF? (I can't recal MAF till VE is right, and I can't get VE right until idle tuning is done).
Right now, with AC tq at 85%, having the A/C on has two effects.
1. Clutch in, decelleration, 0% throttle, idle hovers around 1100 to 1200 rpm half the time. If I turn off the ac, it lowers to 1000 till I get below my throttle cracker cutoff (10mph), then it settles at 850 rpm.
2. For the first minute after starting the car (warm or cold doesn't matter), the first few times I give it gas then let off, the idle will drop to 400 rpm then go back up. Sometimes even stall. After driving more than 60 seconds, it'll NEVER do it again.
What the heck is different about airflow or idle for the first minute after startup?
Hovering idle, and idle dropping seem to be OPPOSITE airflow problems. Hovering is too much airflow, stalling is too little. Is that right?
1. Clutch in, decelleration, 0% throttle, idle hovers around 1100 to 1200 rpm half the time. If I turn off the ac, it lowers to 1000 till I get below my throttle cracker cutoff (10mph), then it settles at 850 rpm.
2. For the first minute after starting the car (warm or cold doesn't matter), the first few times I give it gas then let off, the idle will drop to 400 rpm then go back up. Sometimes even stall. After driving more than 60 seconds, it'll NEVER do it again.
What the heck is different about airflow or idle for the first minute after startup?
Hovering idle, and idle dropping seem to be OPPOSITE airflow problems. Hovering is too much airflow, stalling is too little. Is that right?
Originally Posted by Bink
Yes. Move the values down and monitor your LTITsand STITs as you turn AC on and off - as it ramps in and out.
What's that mean?
Well, FWIW, I've given up on the AC torque for right now.
I put it back to stock, then adjusted my spark tables.
I changed the Idle spark in drive table so that at 1200 rpm, the spark was 2 less than at 800 rpms.
This seems to have helped the floating idle a bit (now it only hangs at 1000 rpm instead of 1200).
I also smoothed the spark between the MAIN spark and idle spark so that transitions wouldn't be too drastic. That seems to have helped the idle from surging back and forth as much.
I put it back to stock, then adjusted my spark tables.
I changed the Idle spark in drive table so that at 1200 rpm, the spark was 2 less than at 800 rpms.
This seems to have helped the floating idle a bit (now it only hangs at 1000 rpm instead of 1200).
I also smoothed the spark between the MAIN spark and idle spark so that transitions wouldn't be too drastic. That seems to have helped the idle from surging back and forth as much.
