92 xj issue 4.0 AW4

Would a bad TPS cause the tranny to not shift untill it reaches almost Redline..

basicly i shifts like i am at full trottle all the time.. even if im slowly driving. also will not downshift untill i am stopped

When my XJ wouldnt shift until redline, a new TPS solved the problem.

Replaced the TPS and that fixed alot of issues

Replaced a lot of issues?? Like what for instance? I've adjusted mine a few months ago and made a change in idle for the better but since has returned to idle at 600 again instead of 750'sh. Adjusted it correctly with digital volt meter.

Random Idle
Hard start
Miss fires
Check engine light
Tranny Shifting like i was always driving at WOT and not downshifting...

Sorry to hijack your thread but I thought it would be better than starting another thread. I have an 88XJ that does not shift out of 1st at all, it just revs. It does this in 2wd, 4H and 4L. Would the TPS be the problem? I have very little knowledge on transmissions so any help would be greatly appreciated. Thanks in advance.

Mauler said:

Sorry to hijack your thread but I thought it would be better than starting another thread. I have an 88XJ that does not shift out of 1st at all, it just revs. It does this in 2wd, 4H and 4L. Would the TPS be the problem? I have very little knowledge on transmissions so any help would be greatly appreciated. Thanks in advance.

Click to expand...

This is with the shifter in (D), yes? The TPS would be the first thing to check. If that's good, I would suspect the rear output speed sensor. If that or the wiring to it is bad, then the trans computer (TCU) doesn't hink you are monving and won't upshift. It's a pain to get to as it's on the drivers side behind the plate that holds the xfer case linkage.

You can check it with a meter by probing the wire at the TCU. With the TCU plugged it and the ignition on, turning the shaft you should see 12 volts dropping to 0 volts once per revolution. On the Renix-era AW4 the sensor is a magnetic switch that closes once per revolution as a magnet on a rotor inside the tailcone turns past it.