started tuning my car with neptune demon and after a few pulls started having some problems and noticed even with car off the tps reading is accurate up to around 80-84% but once you hit that it drops off all the way to -11 until you let back off the gas and step on again then accurate up and down to 80ish % then same thing happens. The throttle body is staying open its something electrical. Should I just try and replace the tps? has anyone ran into a problem like this, could it be computer related?

 

Do you have anything hitting the wiring around the TPS, say like the throttle cable as its being depressed touches the TPS wiring. It shouldnt as they are on opposite sides of the TPS, but some people have pretty crazy wiring harnesses, just a thought.

Other than that, Ohm out the TPS with a meter through its entire range and check for a glitch. That will determine if the TPS is actually faulty.

 

Have you tried to adjust the posistioning of the tps sensor?

 

the wire harness should be fine but I will double check, can I just use the ohm's the computer says? I dont have a ohm meter. I think it didnt even pass 4 ohm at 80% before it drops but I will double check also. I never tried to adjust the position of the tps no, but I seen there are 2 screws or torx screws holding it to the throttle body. This is a jdm h22 turbo setup and it worked fine before but I also noticed the tps sensor has a crack on the plastic, not sure if this really matters but I think I will pick a used one up anyway and try it.

 

Harness checks good, then move to TPS test. No you cannot use the ECU Ohms becuase there shouldnt be one. What you should be seeing is voltage not Ohms. To test the TPS, you must remove the connector at the TPS and ohm the TPS itself. The acutal number isnt nearly as important right now as how much it reads. If you go from 100ohms at idle to nearly 10 at 80% TPS and then suddenly go to 120ohms just past 80%, you found your answer. Replace the TPS. If not and it continues to go drop or increase ( which ever scenarios you have once you start increasing TPS) then the TPS isnt the problem. Linear Ohm drop/increase is a good TPS, Non- linear or erratic Ohm check is bad TPS.

 

I cannot for the life of me get a ohm reading with a ohmmeter. Your right I was seeing volts on the computer via laptop. I checked again when pressing gas the tps reads correct up to around 80% then will drop off to like -11(why negative??) as if you let off the gas, if you let off from full throttle at 80% again it work fine from there down.

Should I replace the tps? This happened while tuning my car on the dyno, is it possible he messed with something while tuning and now its doing this? I know he was adjusting when vtec was to come on and other things. thanks for help

 

Go to File -> Preferences and check what your TPS voltage settings.

They should be around .45-.5 min and 4.5-4.55 max.

If you replaced the TPS in the past then set the voltage scale like I mentioned above and then turn the TPS on the throttle body until it reads 0% with the throttle closed.

Then tighten the screws and check what it goes to at WOT.

It should be around 100% at WOT, if it isn't you can change the scaling with the software so it reads properly. Then hit upload and it will make the changes to your calibration.

 

I checked, I have it at .43 and it says 0, it was set at 4.5 max. I found if I change the MAX to 3.6 it does read up to 100%(unlike before 84%) tps but then like before would drop to below zero, even lower than -11 now and is only physically pushing the throttle down about 3/4. Does that help with anything?

 

Sounds like it is time to replace the sensor then.

 

thanks guys, I replaced the tps today and problem solved!!! looking at the tps after removal it is sticking and doesnt move freely.