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Throttle Positioning Sensor (TPS) won't adjust...sensor or somthing else?

The voltage on my TPS does not change on my 1990 Cherokee when I try to adjust it to the voltages I want it at... I have a random stalling problem and thought I would test all the sensors etc and clean the Idle control motor. i cleaned the motor and still have the problem.. so unless there is a way to test that thing I thought I would check the TPS which is an aftermarket replacement. The jeep runs but it will not adjust... its about 5 volts and .19 the other but it idles properly etc. Is there somthing else that would be affecting the ability to adjust the voltage or is the aftermarket TPS the problem?
 
The TPS should have slightly eccentric holes to allow it to move in the throttle body. Make sure you loosen both bolts enough. If it still doesn't move around, then maybe it is something odd about the TPS and the way the holes are formed.
 
I did the TPS adj on my 88 MJ a while ago. I can tell you that the clymer manual I have tells to check voltage between blue and black or?? whichever the TPS and harness on my MJ is not colored the same as the manual says. If I recall right the way the explain it gives you a constant 5 volts measurement. Of the 3 wires there try probing one of the others. At 0 throttle I think I saw .90 volts and if you crank the TPS up it climbs to 5 or so.
 
I know about the holes, the TPS moves just fine, its just that the voltage doesnt change when it is moved.

I have the Chilton, Haynes manual but they are collecting dust cause I use the Factory service manual, far superior in every respect, followed its instructions and absoulutly no way to make the volatage 0.83 when all the voltages and calculations are made... so I dunno
 
Looking at your last post post, I'm not sure if you're getting the right instructions. There was a service bulletin that may supersede the original FSM instructions. Assuming this is an automatic, make sure that you measure first between terminals A (+) and D (-) of the square plug (the one for the transmission). Voltage should be something near to 5 volts, probably 4.6-4.8 or so. Then move the + probe from A to B, and adjust so that the voltage is 82 percent of the first reading.

If moving the TPS doesn't seem to have any affect on the reading, you might have to take it off and see if it's engaging with the throttle correctly. It's been a while since I looked closely at one of these, but it should be installed so that the prong at the end of the throttle shaft is in constant contact with the corresponding prong on the TPS, with spring pressure maintaining the contact, so that any turning of either the throttle shaft or the TPS itself will result in the variable resistor being moved, hence a change in output reading. If this doesn't happen, there may be a mechanical problem in the way it's put together.
 
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