TPS oscillating at high rpm during ramp run

Hi there, I recently started tuning my car and began the ramp run tune this morning. However, I noticed that the engine was reluctant to rev at 6500rpm. Upon further study of the data, I observed that the TPS was oscillating between 6500rpm and the redline (see attached photo). I attempted another run, and the same issue occurred. It appears that something is limiting the TPS. I have checked the settings in the software but I am unsure of the problem. Any ideas?

Thanks

ML

I would check for a broken wire in your engine harness. Probably the power wire to the TPS, unless you have a short to the 5V that happens at that RPM (solenoid or relay trigger that shorts the 5V supply). I've also seen throttle pots wear out at idle and full throttle (race car applications).

I'll add a few more thoughts which may or may not be relevant since we don't know much about your vehicle:

If it's a drive by wire system verify all inputs, and your throttle target tables.

If the system is torque based, look for any torque reductions.

If the system is turbocharged and throttle is used as part of boost control, verify whether boost is exceeding target or a limit.

I would also verify whether any safety measures are engaging.

Hi Mike, you're awesome! Finally found the TPS was limited by the DBW. The problem has resolved. Appreciate your help. Thanks a lot!!

Wow -- I never thought of a commanded throttle position. MM for the win!

I guess mentioning DBW would have been a good hint to provide. If I were working with DBW, I would probably be logging the TPS and Throttle Aim on the same graph.

Awesome, I'm glad I could help!