So I'm tuning my first direct injected engine with a cam swap and stall converter, and only second direct injected vehicle period. I'm having trouble getting a handle on the idle, and startup was poor at first also until I reduced the cranking VE....which seemed to help startup a lot. Changing the camshafts retard to zero (making it 7 degrees advanced I believe) in 800-1200 rpm columns also seemed to help the startup.
Basically, no matter how high I command the idle speed in the tune, the truck will eventually idle about 50-100 rpms lower than commanded. If left idling long enough it will trigger a code. The strange thing is, the timing value in the main table for the speed and airflow at idle says it should have 30 degrees. I would think that if that is the timing value it is looking at all of the time then if the engine doesn't have enough air flow for whatever reason the timing would atleast be that or higher with adaptive trying to bring the idle up. Rather, the engine will sometimes idle very low just after start up and the timing will be very low, even negative. This isn't 100% consistent however....
When the idle is 100 rpms low, why would ignition timing fluctuate between 10-15 degrees for the most part? Why wouldn't it add timing to bring the engine to the proper speed instead of pulling timing which most certainly seems like why it would be idling low in the first place?
What is the strategy to make these vehicles idle properly when there is no running airflow table, no startup airflow table, no idle spark table, etc.?
I have raised idle speed control reserve 10% at a time without helping the low idle issue. I have also raised the External Load table under Idle Torque Limit.
Does torque management / driver demand have something to do with idle? The throttle response is kind of lazy from right off idle, and a quick stab of the throttle will cause a weird situation where the timing sometimes goes negative and the truck struggles to run for a few seconds.
Attached is both the stock file and my latest modified file along with this mornings cold start and street cruise log. Getting the transmission to shift at the proper times has been a feat in itself with such a loose stall in a 5500 lb 4x4 truck. The stall seems to be atleast a 3500 to 4000....the rpms are practically always 3000+ with even light acceleration! Any help or advice would be greatly appreciated.
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