• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

FSM TPS adjustment directions

dan89XJ

NAXJA Forum User
Location
Oregon
Ok - my haynes manual dosent cut it when coming to telling me how to adjust/test my TPS on my 89 XJ w/auto.

Anyone have a good set of directions ? Perhaps out of a Chilitions manual or something ?

My TPS has like 8 wires.. and 2 black wires.. the Haynes tells me to check voltage from the center wire and the black wire. That dosent work.. I'd have to guess which one is the center wire and which black wire to check.

Any help please !

TIA,
Dan
 
Dan, the readings are taken from the square 4 pin connector (although only 3 pins are used). Test with a straight pin inserted into the back of the connectors, and touch the voltmeter probe to the pins. Pin A is 5v reference. Pin D is ground, and should be less than .1v. Pin B is TPS signal, and should be 4.0-4.4v at closed throttle. At full throttle, voltage should be .2-.5v.

With the throttle closed, note voltage on Pin A; should be approx 5.0v. Then note voltage on Pin B; it should be 4.2v. Basically the Pin B voltage should be adjusted to within 82% of the Pin A voltage. (Loosen screws and turn the TPS until the correct voltage is read, then tighten screws).

Then check for a smooth voltage transition on Pin B when the throttle is advanced. If a spike or open is seen, the TPS is faulty.

All checks are made with the key on, and engine off.

Hope this helps (and is understandable)... :)
 
Here's a condensation of info from a Jeep TSB, which is so often requested that I have it ready to paste in here:

For an 87-90 4.0:

Test is done with throttle closed, connectors connected, ignition on, engine off. Insert probes through back of connectors to make readings. Use a high impedance meter. Adjust TPS by loosening mounting screws and turning in mount.

For manual connect + probe to terminal A, and - to B. Take a reading, which should be in vicinity of 5 volts but probably lower. Note the reading well. Now move the positive probe to terminal C. The reading should be 16 percent of the previous reading.

For Automatic, use the square, 4-terminal plug. Connect probe + to terminal A, and - to D. Note reading, which should be in vicinity of 5 volts. Now move probe + to terminal B. This reading should be 82 % of the first.
 
Back
Top