KEITHKETOLA

Well, a couple weeks ago my 94 xj stopped shifting, so I unplugged the TCM or whatever it is under the dash and have been shifting it manually. Yesterday on my way home from work at about 55 it bogged once, then twice, and progressively got worse and started to backfire and shake real bad almost like the timing was way off, I pulled over and it idled real rough for a minute and died, then wouldnt restart. Had to get towed home, not sure if the problems are related. The TPS and CPS are only a few months old, the battery and cables are brand new also. Where to start?

xjshake

Mine recently did the exact same then... except for my shifting problme came after the crappy running... as for the running I pulled my distributor and cleaned it and my rotor bug and it has been running fine but I still have to leave my tcm unplugged so I can shift manually... we got 10 inchs of rain so I don't know what all it effected... I read a thread somewere that said the tcm ground bolts to the block were the dipstick mounts but they were vague on which dipstick and were it was located... kinda curious on what info everyone has to share

cruiser54

The write-up attached applies to your 88. Good preventative maintenance to do on any Renix Jeep.

On the OP's Jeep, I'm pretty sure the TCU still grounds at teh engine dipstick tube stud. Follow that procedure in the write up.


To both of you, try this. Over near the trans dipstick tube are 2 rather large connectors. One is black and the other gray. These 2 connectors carry all the info between TPS, TCU, speed sensor, and trans solenoids.
Unplug each one, visually inspect for corrosion or bent pins, spray them out with electrical contact cleaner and plug them back in.

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

KEITHKETOLA

tried the distributor thing and cleaned all the grounds...still not a runner

cruiser54

Fuel pressure test?

xjshake

Sorry for high jacking your thread but thanx cruiser

xjshake

I know this is more than likely a dead thread but i found out my issue... There is a resistance wire in line with the tcm fuse.. I replaced mine and now it works

cruiser54

The one right near the fuse? Got a pic by chance?

xjshake

Not right this second hut i can get one... It will be close to the fuse by the tcm