ok so I turn on my car, bam shoots up to 2k rpm and stays. i set the idle air as per post. i then go to set my TPS voltage. at pins A & B with throttle fully closed i read 4.56vdc to wide open the voltage goes down. i pull it put the ohm meter to it, resistance increases as throttle increaces this would mean voltage would decrease. opposed to the tps voltage starting at .54 and increacing to over 4vdc. that would mean resistance is decreasing as throttle is increasing. I have drove this car with this tps on and it ran fine then out of no where the idle sky rocketed. bad TPS? what would make it be backwards. pin A black wire, pin B grey, pin C blue. Any ideas?

 

The grey wire is the ecms 5v reference the blue wire is the feedback to the ecm. The blue wire gets set to .54v at idle. The black wire is the potentiometers ground. The throttle is increased the resistance goes down from b to c. If your looking for a bad tps do a sweep looking for a glitch preferably with a analog vom.

 

well from b to c using a digital mutimeter, the resistance is staying at 429 ohms through full range of motion.

 

Sorry the resistance to ground

 

Set the tps using the black and blue wire

 

well the resistance either dosent move or goes up slightly, from a to b, a to c. the local parts store has one in stock ill pick it up and compare resistance with mine to see the difference. altough i dont know the resistance range of the pot it seems bad to me.

 

tired, voltage starts at over 4vdc and barley changes from idle to wot.

 

That's no good, I can't remember but think the full resistance of the tps is 5-7k

 

thanks for the help, 2 seconds to fix with a good part, 8 hours to determine which part. gotta love it.

 

You remember that learning experience

 

FWIW, the blue wire should be in the middle, i.e. on pin B.


If A is ground, you should be reading 0 V on it, not 4.56. Are you sure you got the pin labels right?