TPS voltage spike - it's not the sensor

[jb89coupe]

Today I noticed that my tps voltage spikes around 75% throttle. The WOT reading is about 4.49vdc, idle is set to .997. It operates smoothly, but at around 4vdc, my voltage suddenly jumps to 0, then to 40(!)vdc, then once it's out of the "trouble zone" it resumes functioning normally.

Of course I thought it was the sensor, so I swapped it for a known working one.. same thing. So, I bought a new one.. same thing.

I've been checking grounds, everything looks fine.. any idea what can be causing this?? My car does buck sometimes around 75% throttle, so I'm pretty sure this is why.

 

[Stang8URMPRT]

Do you have one of those plug in things that make the computer think it's at 100% throttle when you're only at 70%?? Sounds like that's what it is to me.

 

[jb89coupe]

nope.. only thing I have hooked up to the tps is the WOT switch for my zex kit, but I've already disconnected that and it still does the same thing. Something's wacky with the computer/wiring..

 

[HISSIN50]

I would put your meter on the VRef and the supplied ground to the TPS. then open the TPS blade and note if the reading on your meter gets funky around the point where you see the spike. I dont see how you could make 40 volts if you tried (you dont have 3 batteries wired in series, do ya.) .

good luck.

 

[jb89coupe]

I would put your meter on the VRef and the supplied ground to the TPS. then open the TPS blade and note if the reading on your meter gets funky around the point where you see the spike. I dont see how you could make 40 volts if you tried (you dont have 3 batteries wired in series, do ya.) .

good luck.

Yeah I'm not sure about the 40vdc thing.. it's an accurate meter, so it's really there.. maybe some type of stored discharge or something, I don't know. I didn't think to watch the vref while I swept the throttle, I'll try that tomorrow.