Throttle Position Sensor in 1991

[akcskye]

Okay...this isn't an update to my problems with my 1991 Ranger 2.3L Cricket...so I'm making this a new thread.

My dad wanted me to toss this question to you guys and see what you thought.

Dad is checking the TPS (throttle position sensor) in the truck to see if it is faulty.

The instructions given were to attach a digital volt ohmeter and to pull the...for lack of better, "in the engine" throttle open steadily, and that a properly functioning TPS would have a consistent reading, whereas a faulty TPS would have lunges or jumps in the reading.

On Cricket, it has a consistent level when accelerating...I don't know how to explain this other than the engine is off, but I was manually grabbing the throttle thing and pulling it from one side, to the other...which would be the same thing if you were inside pressing the gas.

But anyway, dad wonders if it makes any difference that the TPS doesn't register anything until the throttle is about midway to fully utilized.

It shows no readings from at a "stand still" to half way.

He just wanted to make sure that if it was consistent on the ohmeter, regardless of where it started showing up, if the TPS is considered okay...or should it be replaced because it doesn't register anything until about 1/2 way utilized and up?

Any thoughts? Thanks.

 

[Wicked_Sludge]

sounds like a dead spot in the TPS to me. it should give a steady reading from "idle" to "wide open".

 

[Dave R]

You should have a steadily INCREASING reading as you open the throttle, NOT a steady reading. It should start at about .6-.9volt, with the ignition in the on position and the throttle closed, and should rise to about 4.5volt just before WOT (wide open throttle). If you have no reading and then it suddenly rises to 2-3volt at about the mid point of the throttle's range, then the TPS is definitely duff.

How/where is he taking his readings?

 

[Wicked_Sludge]

You should have a steadily INCREASING reading as you open the throttle

thats what i meant, sorry for being unclear

 

[shadetree]

If the TPS is suspect, replace it. Sometimes, the resistance/voltage readings don't tell you much.

An analog meter is better for checking for "glitches" in the movement.

The total resistance of the device can also increase/decrease causing problems. I have a couple of bald spots from one with that failure.

If the device has high mileage, and cruise, I replace 'em anyway. shady

 

[akcskye]

Okay...this is definitely not a steadily increasing reading...it starts at 0 then jumps to 3 at mid throttle and then on up to about 4.5 wide open.

He is using a digital ohmeter (actually, he used both digital and an old one with the "needle") and testing the TPS where the brown/grey and grey/white wires would connect as the manual he has indicated.

You should have a steadily INCREASING reading as you open the throttle, NOT a steady reading. It should start at about .6-.9volt, with the ignition in the on position and the throttle closed, and should rise to about 4.5volt just before WOT (wide open throttle). If you have no reading and then it suddenly rises to 2-3volt at about the mid point of the throttle's range, then the TPS is definitely duff.

How/where is he taking his readings?

 

[Dave R]

Okay...this is definitely not a steadily increasing reading...it starts at 0 then jumps to 3 at mid throttle and then on up to about 4.5 wide open.

It's definitely bad then.