89Laredo

You need to push the button and push the cable all the way in, it will then ratchet out to where it needs to be when you turn the throttle to WOT. You did the opposite.
If you know someone with a renix, see if you can borrow their tcu for a day...

cruiser54

to clarify this IN/OUT thing, you push the cable housing toward the passenger side of the engine bay with the button pushed.

sansocal

That's what I meant, sorry about the confusion. But yes the conduit is pushed all the way in towards the passenger side. If anything it should be pushed in further.

sansocal

Dropped the pan today and got a nice surprise. The magnets were just covered with shavings and the filter is covered in slimy sludge which I assume is clutch dust.

Idk if this is normal... But anyways I am sure as hell not swapping trannys on this rig so I will fill it up with new fluid and filter and see how long it shifts, then I will sell it with the "have to shift it like a manual" line.

The shards on the magnets are a little bit less than 1/8 inch thick.

sansocal

hahah just a sorta funny side note:

I just looked down at my jeans and there's some atf on them.. It is like glitter cause the metal shavings.

cruiser54

Doesn't look that bad to me.

sansocal

yo crusier i have a question right up your alley. I was messin around with my jeep today and got my multi meter out and hooked it up to the back of the tcu.

on D1 ( a red wire for tps voltage supply) the voltage switches between 4.4 and 1.6. 4.4 when its shifting normally and 1.6 when it does the no shift drama. The voltage to the tcu on pin D16 is always at battery voltage.

So if i'm interpreting this correctly the tcu regulates the juice TO the tps through pin D1, and then the TPS gives back its reading to the tcu through pin D2.

For what ever reason the tcu decides not to give the proper 4.5 volts at times, tps output has to stay low and my jeep dont shift.

Sound right? and my conclusion is i need a new tcu.. and a punching bag for not checking this earlier.

cruiser54

Before I condemned the TCU, I wold perform the instructions in the following write-up without taking any shortcuts, if you haven't already. This wasn't written when I first posted to this thread.


Renix Ground Refreshing
The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, and wasted money replacing unnecessary components.
The components grounding at the dipstick tube stud are:
Distributor Sync Sensor, TCU main ground, TCU "Shift Point Logic", Ignition control Module, Injectors, ECU main ground which other engine sensors ground through, Oxygen sensor, Knock Sensor, Cruise Control, and Transmission Sync signal. All extremely important stuff.
The factory was aware of the issues with this ground point and addressed it by suggesting the following:
Remove the nut holding the wire terminals to the stud. Verify that the stud is indeed tightened securely into the block. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Must be clean, shiny and free of any oil, grease, or paint.
Inspect the wire terminals. Check to see that none of the terminals are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Reinstall all the wires to the stud and tighten the nut down securely.
While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare metal, clean and polish the cable terminal, and reattach securely.
Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for it’s intended use and subject to corrosion and poor connections at each end.
First off, remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire terminal. Reattach securely.
Remove the other end of the cable from the rear of the head using a 3’4" socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely.
A suggestion regarding the braided cable:
I prefer to add a #4 Gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 18" long with a 3/8" lug on each end works great and you can get one at any parts store already made up. Napa has them as part number 781116.
A further improvement to the grounding system can be made using a #4 cable, about 10" long with 3/8" terminals at each end. Attach one end of this cable to the negative battery bolt and the other end under the closest 10mm headed bolt on the radiator support just forward of the battery. Napa part number 781115.
　
　
If you want to upgrade your grounds and battery cables in general, contact Jon at www.kelleyswip.com. He makes an incredible cable upgrade for a very reasonable price.
　
Revised 11-28-2011

cruiser54

Brain fart on my part. Just thought of something. Don't disregard the previous post as that needs to be done to every Renix Jeep IMHO.

Do this in addition as it fixed an odd shifting problem on my wife's 88 XJ.

Over near the trans dipstick tube are two connectors that carry all the info between TPS, TCU and trans solenoids. One is black, the other is gray and they're both about 1.5 inches square. Unplug, inspect, clean with electronics cleaner, and plug them back in. One of mine had corrosion in it.

Why not do the same to the TCU connector?

RCBRC is the Renix mantra. Refresh Connections Before Replacing Components.

sansocal

thanks for all your help guys, ill post up later after what i find. should be able to fix it tonight after work.

cruiser54

Remember: RCBRC and no shortcuts.

sansocal

sorry for taking to long to update but i have been super busy with school and work. anyways it was the tps that was bad!
when it would fail the tps would still send voltage through but it would only flucutate between 1.6 volts down to 0. The reason this slipped past me was because the resistance test still showed changing resistance when giving it throttle (like it should) but the range was much smaller. I never thought about that part and the lesson learned here is that its probably best to follow the trouble shooting guide that people have made.

thanks for all the help!


p.s. i love my jeep again

cruiser54

I love happy endings...