aw4 not shifting (need REAL answer)

[lawsoncl]

Might want to look here http://www.transonline.com/transdigest/magazines/1997-10/Shift%20Pointers/index.html

Some good info, some I wonder about, guy says the default for a no power TCU is 4th gear?

That is correct. The first test in the FSM is to disconnect power and check that you get 4th gear in (D), 3rd in (3), and 1st in (1-2). The NSS normally can't cause this problem unless it's really messed up and way out of adjustment and indicating the shifter is in 1-2 or 3. Easy check is to simply unplug it and see if the problem goes away because there are no connections made when the shifter is in D.

I was thinking he may have damaged the rear output speed sensor as well, but that would cause it to stay in 1st and maybe shift to 2nd near redline.

 

[cal]

It's taken a year and a half to figure that out?

 

[centralmax]

ha, no, but i never finished the thread and i figured someone might be able to use this cause it has some good troubleshoot info...

 

[johnnybebad]

this sounds like my problem....
I have no kickdown and no Overdrive. Checked the fluids ,they were fine, changed the TCM and had overdrive for one day. I changed the tranny because I got a good deal on a low mile complete powertrain and besides the old one was leaking bad and was sluggish.
the new tranny shifts great, but still no O/D.
If I push the pedal to the floor, it actualyl shifts into O/D and bogs, and when I release it goes back to 3rd gear.
This is an 89 XJ by the way, and I have changed TCM`s already.

 

[lawsoncl]

Check the TPS sensor. Also check the switch at the brake pedal (white, high up on the pedal arm), if that's bad or just gunked up the TCU will think you have the brakes on an keep the t/c unlocked.

 

[JoBo]

I think you have the wrong THROTTLE POSITION SENSOR on your xj. Renix models have a different TPS for the auto. It works backwards then the standard shift one. That explaines your getting OD when you mash it

 

[johnnybebad]

Check the TPS sensor. Also check the switch at the brake pedal (white, high up on the pedal arm), if that's bad or just gunked up the TCU will think you have the brakes on an keep the t/c unlocked.

that is a very good possibility, I thought of that actually, thanks for bringing it up !
Going to swap on another TPS also and see where it gets me.
Thanks for the tips

 

[lawsoncl]

I think you have the wrong THROTTLE POSITION SENSOR on your xj. Renix models have a different TPS for the auto. It works backwards then the standard shift one. That explaines your getting OD when you mash it

The ODBI and Renix TPS sensors are not interchangeable as the throttle body is quite different. The Renix manual TPS just has a single connector for the engine computer. The Renix auto TPS has two connectors, with one going to the engine computer and the other going to the trans computer. In all cases, the TPS signal going to the engine computer runs 0-5 volts. The second signal that goes to the TCU does run backwards from 5-0 volts, but since the connectors are different it's almost impossible to get them swapped. On the later models, the TCU gets a throttle position signal from the engine computer.

On an 1989 it's pretty likely a bad TPS, especially if its the original sensor. They do wear out internally.

 

[johnnybebad]

yeah that is what I`m trying first. Going to take some readings with the DVOM and I have a spare intake from a 90 with the TPS still on it so swapping won`t be a problem.

 

[johnnybebad]

thankfully a used TPS solved my problems !

 

[Wallyman]

I just became a member of the "replaced my TPS and all is well" club.


Just to share my little story.....It started raining like a monsoon here by Galveston island, TX and as i had been driving around town ...in the water (yeah, im that guy that goes out just because its flooded :looney: )
Once i got back, and headed out again a few hours later (no longer raining)
my transmission started doing what i would describe as free runnign instead of shifting into 3rd.Or sometimes 4th. Ive seen "slipping" posted everywhere. I cant say i felt like it was slipping, it seems more like it went into unlocked mode and the TC unlocked. either way,...it would rev up to redline before shifting into 3rd...if it shifted..
So it was all messed up....I read and read and read... and broke out the Fluke DMM from the ol Craftsman roll away tool box (fathers day gift, YES!!!!) and measured the TPS. it was smooth up and down, but the Voltage level was just over a volt under what i could read it as needing to be.No matter what i did adjustment-wise. I said screw it, went to Auto Zone..$92.00 later
....it started up.. and shifted the way it was meant to. A little adjusting on that TPS and im up and goin. Mine didnt even feel like it moved rough. it was as smooth to the feel as the new one and not much dirtier. But i guess it got wet....and they dont like getting wet...
It can be decieving. I learned to trust the stories of the people on here ever since the CPS was causing my engine to die after warm up. NEVER would have thought a crankshaft position sensor would kill a running engine. So i now believe a throttle position sensor can skew a transmissions shifting patterns.......
So ummm i now get my chance to say.....
a new TPS did it for me... : )