Gents,

After calibrating the TPS, I might see anywhere from -0.3% to 0.4% with my foot off the pedal. Is that normal?

Thanks,

 

unscrew the tps, and rotate it away from the extreme (CW), re-tighten, recalibrate. does that make it more predictable?

 

+/-0.4% is a very small deviation. I believe its an 8bit ADC so you are looking at like a +/- 1 bit deviation, or less. depending on how they do it. Which is less noise than I had on my old tps.

I retract my previous statement. Looks like its at least a 10bit ADC. Either way, that is not a lot of noise. And in my experience that is normal.

 

Thats pretty normal. You may even see different values running versus not running.

 

While 0.7% is a poor noise/accuracy level, it's not unheard of with Megasquirt measuring stock TPS with stock wiring. But, for what the TPS is used for it's not out of acceptable range. As long as your TPS never rises above your idle threshold (maybe it should be 1%?). I don't see that little bit of fluctuation affecting TPSdot enough to throw any of your accel enrich tuning out of whack. Launch control and flat foot will have thresholds that are far enough away from where you will use them that it won't be an issue either.

 

Please report back after trying Brain's suggestion. Inquiring minds want to know.

 

Brain,

I have a spare TB assembly. I inspected the TPS and attempted to do what you suggested. There is only one possible mounting position of the TPS on my '99 TB--the mounting angle can't be changed. Are you suggesting fully exercising the spring tension might affect the calibration?

Thanks,

 

looking again, it looks like this may only be an NA thing:

 

Thanks for reporting back.

My '99 probably has a a Zero that moves a less than 1% over multiple log. My OverRun threshold is set at 1%, my CLI threshold is at 1.5%, and my actual Logged range is -0.8 to -0.3 or 0.5% range on a single, long log, and also shows -0.8% as a minimum on many logs from Jan through today.

If I were to re-zero my TPS, I would likely change the OverRun threshold to 1.5%.