I searched around and couldnt find anything on this, so i thought i'd ask. I installed a variable TPS on my 1.6 and it seemed to be working well until now. I am tuning closed loop idle now after hitting the dyno and being laughed at for having to floor it while hot starting on e85. Anyway, i watch the accel enrich wizard table and i can see the thing jumping around as opposed to being solid at pure idle. Also, when i go to calibrate it, the base "closed" position will jump around from 140 to 170. Seems my full throttle position is pretty solid at 730ish and doesnt change. I have checked the physical cables and connections and everything seems good. My thoughts were if this is measuring a resistance on that solenoid, if i put i capacitor inline it'll about defeat the purpose of it. My question is what can i do about the jumpy readings at closed throttle? The sensor is less than a year old and have doubts on it being bad since it reads well when not at full closed position. Any ideas?

 

is the physical position of the sensor fully backed when at 0%?

 

I am 99.99% sure it was initially when i set it up, but its probably worth a second look. I'll take it off and look. Standby.

 

unbolt it, rotate it away from full stop, then bolt it back in place. try again; report back.

what's the current tpsdot at idle?

 

so it was. Funny thing though. I have been battling this only when the car is on. While its off, its pretty darn stable. I just adjusted it by turning it as far "back" as it goes. Was able to just loosen the mounting bracket and turn counterclockwise as much as the mount bracket would allow. Started it up, and it seemed OK. I have done similar things to re-calibrate it in the past, but seems to keep coming up over time. Oh well, guess i'll just do this every 3-4 months. Seems easier than wasting a bunch of time on now.

 

Where is the tps grounded?

It's possible it's a grounding problem, look over the images in this thread. https://www.miataturbo.net/megasquir...grounds-74699/

I had a similar issue when I installed my MS, and it ended up being grounds.