Idle dips and timing locks... need advice
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10 Second Club
Joined: Jan 2010
Posts: 2,317
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From: Hurley, VA
Idle dips and timing locks... need advice last idle log.hplTaylor final tune.hptPulling in and out of gear idle is stable but with throttle blips in gear it dips down and timing will lock as it hunts then timing starts bouncing and idle stabilizes again. I've tried adding a ton of air. I've upped timing dropped timing everywhere. I've zerod the over and under speed tables. I've had them 15 and 15 across the board. Still dips but once timing starts moving again idle stabilizes. Anybody have any ideas. BAF is good. RussK config was done. Heres a copy of the tune and a log.
copy and paste all data from Idle > Airflow > Throttle Follower; Throttle Cracker; Rolling Idle and see what that does for you. My software is set to metric in case it doesn't automatically switch over when you open it. The idle areas of your MAF, VE, and spark tables shouldn't be causing you problems.
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
Try setting your High and Low octane tables the same as your idle tables, 0.8 g/cyl to 0.52 g/cyl, through 1200 RPM. The top left corner. Your main spark tables are at 26* whereas your idle tables say 19*. It's best to make them match in the idea areas. Personally I also make the rest of the idle spark tables match what my high octane (low octane for SD tunes) says on each rpm column. The tables don't match so don't copy and paste the whole thing. Just copy the columns straight over, 0, 400, 800, 1200, 1600, etc.
Also add some more inputs to your scanner. It's hard to see what your spark is doing since you're not logging g/cyl (cylinder airmass). Add these PID's to the scanner to help troubleshooting:
Cylinder Airmass
Dynamic Air
Idle RPM desired
Idle base airflow (park and gear)
Idle spark advance
Long Term idle trims (LTIT)
Hopefully the spark table fix works to fix the spark "getting stuck" for you. Start with that, get another log and post it. Idle tuning is one of the hardest things to get right. So don't feel bad, you're not alone on this one. It's tricky.
Also add some more inputs to your scanner. It's hard to see what your spark is doing since you're not logging g/cyl (cylinder airmass). Add these PID's to the scanner to help troubleshooting:
Cylinder Airmass
Dynamic Air
Idle RPM desired
Idle base airflow (park and gear)
Idle spark advance
Long Term idle trims (LTIT)
Hopefully the spark table fix works to fix the spark "getting stuck" for you. Start with that, get another log and post it. Idle tuning is one of the hardest things to get right. So don't feel bad, you're not alone on this one. It's tricky.
I tend to find making the tables match does not help. You either idle with too high spark timing or you are sluggish off every red light. I tune the main tables to maximize power and set the idle tables to 18-ish. 0 and 400 columns to 32 as a stall saver.
If you are sitting still and making throttle stabs, and it undershoots on return to idle, that is telling you you need either more base airflow or your proportional idle air needs adjusting. Once adaptive spark kicks in it stabilizes. In some ECU there is a timer delay before going into adaptive spark in the engine idle area. Set that timer to 0.1 seconds may help.
Add the channels to your log that chopper suggested. That will help a lot for correcting commander airflow
If you are sitting still and making throttle stabs, and it undershoots on return to idle, that is telling you you need either more base airflow or your proportional idle air needs adjusting. Once adaptive spark kicks in it stabilizes. In some ECU there is a timer delay before going into adaptive spark in the engine idle area. Set that timer to 0.1 seconds may help.
Add the channels to your log that chopper suggested. That will help a lot for correcting commander airflow
