i bought a new tps because i was getting a code 13 and my o2 sensor and all the wiring was good, so i plugged the new tps in and hooked the multimeter up to it set it to 20volt dc. the tps reads 5.02 volts with the car off key in run position and the voltage does not move while adjusting, and when its bolted down, when i move the throttle to wot the damn thing still reads 5.02 volts doesnt change one bit....the old one was doing the same thing....are they not adjustable on the v6's?

 

You are probably testing the wrong wire. The top wire gets 5V from the ECM at all times. The middle wire is the one to test.

Also!!!! The procedure described in the Haynes manual says "...with the exception of 3.1L V6 models..." but does'nt say what to do. I don't think the TPS is adjustable for this car and I think I read that the ECM just uses the initial closed throttle voltage as a zero reference.

 

can anyone else verify my problem here? are they supposed to be adjusted? i didnt get a reading from any wires but the top which i thought was negative and the middle which i thought was positive could not get a reading from the other wire(s)...

 

well i know there is a difference between the early and later TPS's where the screws go thru it. the holes are elongated on the older ones, allowing adjustment.

 

You need to have the connector secured to the TPS sensor. Turn on the ignition. Probe the 'B' and 'A' terminals on the TPS. Youc can look at the old TPS closely to see which terminals are which. The 'A' shoudl have a black wire, the 'B' a blue wire, and the 'C' a gray wire. The TPS must be connected to the throttle body, and the throttle must be closed, or the spring on the TPS lever will operate teh sensor to the full open position. It has this spring to maintain tension agains the throttle shaft for a consistent indication. When the TPS is installed, you must be certain the tang on the throttle shaft engages the lever on the TPS itself.

 

hmm, maybe i do have the tps twisted in the wot position, cuz when i put it in it wouldnt just push right in i had to rotate and push it in and then rotate it into place so i could bolt it in....and the bolt holes on my 91 aren't elongated, for whatever reason i dont know theres very little you can move this thing though, in either direction, im gonna give it another shot tomorrow.

 

ok, update:

jumped those other 2 connections, finally got the voltage readings i wanted but theres only one problem, at idle the tps has about 4.99 and at wot the volatge read about 0.60 or something to that extent, but isn't it supposed to go down when its at wot? or do the 90-92 v6's ecm use different voltage references? because i cannot even twist and turn this thing to bolt up right without getting these same readings everytime. i mean the car seems to idle great driveability is fine other than a tuneup thats been well in order weather permitting i will get it done soon, but is whats happening supposed to? or am i an idiot that should just send this to the shop and have them adjust it?

 

also i suspect that the tps is still my problem because throttle response has improved but is still a little crappy at times. and the sensor is good because the voltage increased in very steady incriments .01 at a time depending on how much u move the throttle manually

 

I played around with the TPS on my 91 Camaro with 3.1 years back. The TPS was NEARLY non-adjustable. You put it in, tighten the screws down and have just the tinyest bit of adjustment wiggle. So little I would say it's effectively non-adjustable. It's, near as I can tell, idiot-proof as far as installing it.

I don't recall what my voltage readings were but I don't think they went decending with more throttle.

Regardless, unless you invented a new and improved way of installing the TPS wrong, you can't screw it up. The plug only goes on one way and the TPS only fits on one way.

If you want to test voltages why not remove it from the TB and turn it with your finger while you check voltage readings? That would certainly eliminate any incorrect installation problems from the situation.

 

Correct. The 90+ MAP based ECM's just used a reference signal. When the key is turned on, it what ask the ecm what voltage it was recieveing, than it wuold set that as 0% throttle. As long as it was in a set range, all is fine.

 

hey believe it or not when i take the tps off and spin the inside dial thing with my finger, the voltage goes down, but after installation, the tps reads about 5.04 volts and descends to about 3 or 2 point something i can't remember now...isn't the tps supposed to increase in voltage? this thing is just finding new ways to **** me off...also the car runs really good, the only thing when i give it quick bursts of throttle while under the hood she sounds like shes suckin too much gas and the car starts to sputter and ALMOST dies but regains the idle back, car also idles erratically with the idle bouncing around between 800-1000rpms. its almost like the car isn't getting efficient spark but the plugs are fine, just need to check the wires/cap/rotor/coil for any problems but whats wrong with this damn tps?!?! its a wells brand by the way

 

It seems that you are using an incorrect ground (negative) reference point.

• Connect your meter negative probe to the BLACK wire at the TPS.
• Connect your meter positive wire to the BLUE wire at the TPS.
• Read the voltage at the closed throttle position. I'm guessing it will be 0.60V, which is perfect for a non-adjustable TPS.

This ALL needs to be done with the TPS properly mounted to the throttle body, and connected to the wiring harness.

Your voltages appear to be correct if they were only reversed. It seems that your TPS is working just fine. I'll bet you a quarter.

 

i have the prongs in the right slots, red to blue black to black and still the same the voltage reads 5 volts at idle and as you move the throttle it goes down.....maybe the new sensor i bought was bad???

 

You have the wrong sensor. I came across this several years ago.
There is an application where the thottle plate rotates the opposite way but I can't remember what it is.

 

Kyle could be on to something.

Although my experience with this combo is limited, I feel like I would have remembered something as odd as TPS voltage going DOWN with increasing throttle opening. I don't recall ever running across that situation.

Kyle could be right about that. Certainly, for the cost of another TPS (from a different parts store) it's worth a quick sanity check.

 

On Gm's the voltage always goes up. There is a throttle body that rotates the opposite direction, I am thinking it was an early 2.8 fwd but not sure. Mounting and connector the same.

The tabs will go on the back side of the shaft blade and the spring in the tps will let it "follow" the throttle to wot, thinking it was closed.

You just about have to rotate it 1/2 way around to mount it.

 

Just don't tell anyone where he got it...

Obviously, we're missing something on this situation. Was something else changed?

How does the meter read the battery voltage? +12 or -12V?

 

the meter is fine the connections are good, and yes the voltage goes down as you move it to wot, maybe i will go out and get another tps from somewhere else, i got this one from autozone, i have an acdelco parts store around the corner ill try there next...

 

and the multimeter was set to 20V DC just to clarify myself, and the readings were all + not -