Throttle Position (TP%)?

[beav]

First off, when viewing TP% in EFILive, what PID should I be looking at? I am using Destroked's XFC with a ~0-5vdc input from the Dodge APPS.

I have configured the XFC to see the actual min and max voltage.

Here's where I am confused...when using the scan tool to read the TP% from the Cummins ECU, it is scaled 1:1 (0-100%) as I move the pedal. However, when using the scan tool on the Allison TCM, it is not scaled as I would expect it at all. For example, with the pedal position from 0 to about 20%, it translates to 0-75% on the PID "GM.TP". From 21-100% pedal position, the PID reads the rest of the range 76-100%.

I have not seen any way to scale the input in EFILive. So, the better question might be, what else is considered when generating the GM.TP PID? Seems like I have read something somewhere about the MAF sensor being in the mix.

Thanks for any help!

[beav]

Here is what I see from the XFC. Not sure if it is the PWM1 output from the XFC that is sent to the TCM (over J1939 CAN), but it does somewhat look similar to the GM.TP PID output in EFILive.

Notice that the PWM1 output has a baseline of 7.4 before even ramping up with the actual throttle position.

Any thoughts?

15418

[beav]

Ok, update...got the transmission shifting much better now. The "effective throttle" reading in EFILive is not spiking so quickly and the shifting is occuring almost as expected. I made a change in the XFC by adding .5v on the closed throttle scaling parameter. This slightly squashed the effective throttle scaling enough to get it into a more effective range.

I doubt that my tuning is complete, but hopefully as I continue to drive it, it the TCM learning process will make it even better.

I hope this info helps someone else.