Hey guys, I'm new around here, and have had the truck in sig for about 6 months. When I first got it, I noticed that past about 40% tip in on the pedal made NO difference in acceleration until I was far enough in to downshift. I hooked up my Torque Pro, and Dash Command, and sure enough, TPS never exceeds about 40-45% unless you are really in it and usually about about 3500-4000 RPM. Is this common on these trucks?

 

Sounds like a bad sensor to me.

Welcome to DF!

 

Which one?

 

Is there more than one? I am not as familiar with the 3rd gen systems.....

 

Just a presumption, but I would assume there is a position sensor on the actual throttle pedal, and a sensor / motor on throttle body to match position. On mine it almost seems like ECM mapping more than a malfunction. I don't know if it's trying to prevent engine load or detonation or what. It just seems like if the RPMs aren't above a certain range it won't give more than 40 to 45% throttle

 

Sensor output shouldn't be affected by anything other than how hard you are stepping on the pedal.

Key on, engine off, bring up that particular bit of data on your scanner, and then slowly press the pedal down. It should rise smoothly as you press it down, if it doesn't, then, it's broke.

 

Put my scanner on it this afternoon. Have One TP percent in module 10 that scales evenly koeo. Have another TP percentage in module 18 that does not move with the koeo and sitting in the driveway engine running maxed out at about 22. I imagine that's the one torque was monitoring. It also occurred to me that there's a warning indicator for fly-by-wire malfunctions and I've never seen it come on other than the test cycle. The one I moniter with torque maxes at about 40% until down shift then will come up to 60% or better and keep climbing if I give it more. It also seems to correspond a little with calculated engine liad.

 

Wonder if that is actual throttle opening.

 

Judging by the seat of my pants, I'd say yes. So what I think is the mod 10 is pedal sensor (input) and mod 18 is TP command as scaled by the ECU. Just wondering why the command is so reserved in higher gears, and more importantly if that is common on these trucks

 

On that, I have no idea.

Suppose a 'relatively....' easy test would be to test drive another truck, with your scanner plugged in. See what the numbers look like.