Boost or RPM limiter? Won't shift....
Hey guys,
Need a little insight if anyone can provide any....
I have a 2006 Cummins I'm tuning for a customer, S366, 100hp injectors, single tune. Truck runs good, made 658 on the dyno... but I can't get the thing to shift quite right, allow me to explain
Truck had a boost fooler on it intitially. Prior to tuning I took it off.... tuned it, went for a drive and noticed at 3000-3100rpm it acted like it was bouncing off a rev limiter. I tried a couple things to no avail, plugged boost fooler back in and it shifted no problem and ran through all the gears.
Later we noticed the truck would basically not even do a burnout when you power braked it.... pulled boost fooler off and bam! Plenty of power to pull through the brakes down low, but still bouncing off a limiter at 3000-3100rpm.
When the limiter sets in, the boost gauge reads 35-36psi everytime, if you let up on the pedal it will shift, then you can put it to the floor and make 45psi of boost no problem at all. Which confuses me because with the knowledge learned from the boost fooler I was certain it was boost limiting. My wot shift points on this truck are set at 3300 rpm, I haven't tried lowering it back to stock shift point, but I have a sneaky suspicion that it would work fine, I've got a guy in ohio running compounds on a truck with 3050 rpm shift points and he hasn't missed a beat with his shifts making 50psi......
So what table am I missing? I've removed every possible limiter I can find, and still can't run the shift points I want.....
