6716 said:Just curious.
the roadie said:Just more details for the curious. The butterfly valve is moved by a stepper motor. And the TPS is actually TWO potentiometers, and the PCM compares their outputs to make sure it has an accurate reading of the butterfly valve position. If they ever DISAGREE from a bad sensor or broken wire, the PCM goes into REP mode so you can limp home, but that's designed so a single failure won't result in WOT behavior that can kill you. Same thing for the accel pedal. Two sensors for redundancy.
Playsinsnow said:A dirty throttle body will cause you to be sluggish and result in poor performance and mpgs. Or worse. To add to what it "controls".
the roadie said:Just more details for the curious. The butterfly valve is moved by a stepper motor. And the TPS is actually TWO potentiometers, and the PCM compares their outputs to make sure it has an accurate reading of the butterfly valve position. If they ever DISAGREE from a bad sensor or broken wire, the PCM goes into REP mode so you can limp home, but that's designed so a single failure won't result in WOT behavior that can kill you. Same thing for the accel pedal. Two sensors for redundancy.
AtlWrk said:It's actually a geared down regular ol' DC motor so no worries there.
the roadie said:Just more details for the curious. The butterfly valve is moved by a stepper motor. And the TPS is actually TWO potentiometers, and the PCM compares their outputs to make sure it has an accurate reading of the butterfly valve position. If they ever DISAGREE from a bad sensor or broken wire, the PCM goes into REP mode so you can limp home, but that's designed so a single failure won't result in WOT behavior that can kill you. Same thing for the accel pedal. Two sensors for redundancy.
Texan said:I retired about the time the "other" car company was having sudden acceleration problems. I was able to watch the testimony before congress
about the problems. Going from memory, it was stated that the two signals from the pedal to the TPS were both going from like 1 volt to
5 volts from idle to WOT. I got out my TB shop manuals and noticed that my Chevy had two signals that went in opposite directions. One went
from 1 volt to 5 volt+/-, while the other went from 5 volts to 1 volt. This made more sense to me for drive by wire. I have often wondered if
this may have been part of the problem. The other car company was/is secretive about what was in the computer memory.