Throttle Position Sensor - '92 4.0L 6 Cyl Auto Trans

[GregA]

Here is a question for you technical types.

I have been having issues with WHEN the transmission shifts. I suspected the Throttle Position Sensor because when I let off the gas pedal, I can make it shift sooner.

When I looked at the Haynes manual and online (autozone) for how to test it, it said to measure the voltage at the center wire at zero throttle and full throttle, and to make sure the voltage moves up "smoothly" along the range (which it did).

BUT ...

The specs also say that it should START at about 0.5 to 1.0 Volts when the throttle is closed, and go to about 4.0 Volts at full throttle. I have the 4 Volts at full throttle, but is shows about 2 volts as a starting point (throttle closed - idle position).

So my question is: Would this cause the "late shift" symptom that I have been having?

My theory is that the computer "thinks" that I am accelerating "harder" than I actually am, and delaying the shift point.

Any opinions?

Take Care,

[GregA]

Update:

When I took the Throttle Position Sensor off, I discovered that the voltage can be adjusted from about 0.5 volts to about 4.2 volts if the sensor is turned with a screwdriver.

I also discovered that to get the sensor back in, I had to turn it about 20-40 degrees. This allows the throttle shaft to slip past the "tangs" (tabs) inside the sensor. So when I turned the sensor to get the screws back in, that is what causes the voltage to go up to 2 volts.

So I guess there are a couple of possibilities:
1) The throttle shaft has been turned somehow (previous shop?).

If the throttle shaft has been turned, can it be "adjusted" back some?

2) This is the wrong sensor? It says "CTS" on one side and has the following numbers on the other side (top to bottom):

0932A
5234904
24936

Thanks in advance,

[pat8942]

Just get a new tps and it will shift like a new one.

[GregA]

Originally Posted by GregA

So I guess there are a couple of possibilities:
1) The throttle shaft has been turned somehow (previous shop?). If the throttle shaft has been turned, can it be "adjusted" back some?

The throttle shaft was fine - Nice & Straight

Originally Posted by GregA

2) This is the wrong sensor? It says "CTS" on one side and has the following numbers on the other side (top to bottom):

0932A
5234904
24936

Not sure about this one.

UPDATE:

I finally got a replacement part and installed it today after being out of town and the part being "out of stock" at my favorite parts place.

After replacing I now get the measurements that should be there. It starts at 0.80 volts at idle setting and goes to about 3.8 volts a full throttle.

The Good News: It seems to shift MUCH MUCH BETTER (Nice & Smooth & at what appears to be the right times)
The "Not So Good News": This is my wife's Jeep and she needs to drive it and verify that it is "fixed" and she is visiting her Mother for a few days.

Question - Should I:
1) Tell her I think it is fixed, or
B) Just let her "notice" and wait for her to tell me?

Take Care,

[pat8942]

How about C Tell her it's fixed

[FlatLanderHandicap]

Would a TPS be linked to idle problems or engine stalling while driving? I ask this because my TPS is bad on a 92XJ w/ 4.0L HO. I'm gonna replace the TPS today. If anyone has any insight, i'd appreciate a response. I'll post a follow up after the swap.

[hiduke89]

IM not exactly sure on this one, but i was having some major troubles with stalling while driving so i decided to try to adjust the idle. that worked with the stalling but then the tranny was shiftin way late so i installed a new tps and everything is running great so im GUESSING it does but don't take my word on it im still new to the jeep buisiness.

[FlatLanderHandicap]

well either way...I think we are both right. THe TPS is the biggest bang for your buck when it comes to repairs. 25 dollar TPS from rockauto.com fixed everything. Took 5 minutes to swap. The Jeep has never run better!