Help with bucking in part thottle cruise

[turboffr]

I've got an LS3 in 2003 my C5Z06 with a 232/240 @ 112 Pat G/Cam Motion cam. I'm trying to clean up the part throttle bucking from 1600-2200. I've removed timing in lower load cells (running around 22-24 degrees in problem areas) which seemed to help a little, and latest tune I commanded ~13.8 AFR to richen it up a bit between 1600-2400 by setting PE enable TPS to 0 in those cells and 1.063 EQ ratio for the same RPM's. That made it better, but there's still some slight bucking and I'd prefer not to have to run PE in part throttle. Any other suggestions? Tune is attached. Thanks

10.3 working.hpt

[cobaltssoverbooster]

have you spent any lengthy time to adjusted throttle cracker? it can have an effect on the cruise range if the requests are too high or too low.

my reference on it is this http://www.hptuners.com/forum/showth...rottle-Cracker
post #7

[turboffr]

thanks I'll take a look at that link. the car had a tune in it before I bought it and it looks like the cracker may be disabled??

[cobaltssoverbooster]

i hope not. throttle cracker and follower are very important for cam upgrade engines; particularly if they are paired with a manual trans as the direct connection to the gear box doesn't wash any of the engine running issues out before it hits the driveline like a converter can.

[turboffr]

I saw it when going through the tune. I recall correctly enable mph = 1 and disable mph = 2. It was opposite of stock tune. I read that as disabling at 2 mph so it's only working at idle?

[cobaltssoverbooster]

yes that would be correct as long as the vehicle speed is below 1 mph

[turboffr]

Right, so how is airflow from cracker table effecting cruise bucking if disabled at 2mph.

[cobaltssoverbooster]

As engine airflow moves arouND the airflow changes. The Crack and follower tables are designed to alter the airflow requirementioned to maintain a smoth engine output.
The best way I can describe it is its like tuning iac but for dynamic opperations.
I have always had the feature enabled.

[turboffr]

I was able to clean it up quite a bit by lowering timing to 22 and retuning my VE table in effected areas. Much smoother now, and I'm not commanding PE in cruise anymore either, but I still have some bucking right at 1600. Not sure what else I can do to eliminate it aside from trying to richen it up right around 1600 by running PE there and commanding something richer than stoich.

[turboffr]

latest tune attached. If anyone sees anything out of place that might help with the bucking around 1600 please let me know.