I just got my usb cable and some free softeare that i can watch the pcm with, when the car is floored it only reads just over 80% throttle and like 3.57 volts. I checked to make sure the throttle is actually opening all the way, and it is. Could this be caused by a bad tps? Any ideas appreciated.

Thanks Scott

 

What valve does the TPS read when the TB is closed at idle?

 

Perhaps slot the TPS so you can rotate it till it reads 100%

 

it reads too high at closed throttle, it is .7 volts. I slotted it before to get it down to like .5 volts so it must have moved i guess. I check it right after i slotted it and t still read 100% but that was last summer.

 

0.70V is not too high at closed throttle. Most stockers read 0.65-0.67V. The PCM will accept any value from 0.20V-0.90V (that's why its not slotted, there's no need to adjust it), and prorate the throttle position percent (TPP)between the measured value and a WOT voltage of about 4V higher than the closed throttle voltage.

Use the scan software to watch the TPS voltage as you slowly rotate the blades from full closed to full open. Should increase by about 4V, and the voltage rise should be steady.

Check voltage from the gray wire to the black wire, to insure you are getting 5.0V reference from the PCM.

 

alright, i will make sure it has the full 5v first, i watched it when i opened the throttle manually by hand and it went to 3.7v. Thanks for the input