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Torque converter I guess???? HELP NEEDED

D

Dfete1

NAXJA Forum User
Location
Palestine, Tx.
My wifes 94 XJ 2wd 4.0 auto has been stalling and bucking. I figured ignition or something. Starts losing power and dying usually at speed. I have a running XJ that i have been swapping parts with. So far I've replaced dist./cap,rotor, coil,wires,cps,Tps,iacv,fuel filter,map,pcm,catalytic conv,coolant sensor,and I'm sure theres more. If i accelerate hard or kick it down it bucks,backfires ,and dies sometimes. I can kick it into neutral and rev it no prob. The only thing left I can figure is torque converter. Oh yeah and I check fuel pressure and regulator,and all the relays. I'm running out of parts to swap. Please someone save me.
 
If the upper white brake switch does not disengage, it can keep the TC locked up and stall the engine. It is the upper switch, not the brake light switch!!! IT is way up above the brake peddle deep under the dash, and hard to reach!!!

I would also check for a loose wire, main power at the battery or main power control center, and check for a vacuum leak in the vacuum line (or nearby) on the line to the MAP sensor. Also make sure the O2 sensor has 12-14 volts to the larger of the 2, non-black wires, to run the O2 sensor internal heater.
 
Theres no second brake switch. No vacuum leaks either. I dont know...Gonna check O2 sensor tomorrow.Tried to do a stall test and it just smokes the tires. When you floor it driving driving it will die. This thing usually runs better than new.Idk
 
Ecomike,
In our previous threads about this white switch, I said the infamous white switch was eliminated somewhere between 1990 and 2000. At that time this function was integrated into the brake lamp switch. When this was done, the "switch" went from 4 terminals to 6. I just borrowed a copy of the 1993 wiring diagrams to verify the TCU is using the brake lamp switch. It looks like the white switch is probably a RENIX thing that was eliminated by Chrysler when they made all the other significant engineering changes in 1991. I wonder what they did with the vacuum dump?

Dfete1,
If you want to konw what theTCU is doing with the TC, you really need to monitor the output to the lockup solenoid. Get a T pin to backprobe the TCU connector C-14 (TC Lockup). Dress your meter probes so they won't get knocked loose, set your meter on the console, and take it for a ride. If the TC does not lock and unlock as it should, you could have a problem with the brake light signal. Backprobe the TCU at connector C-10 (STOP LT SW) to verify that signal. If you find your TC is not locking, you could pick up a bonus 3 MPG on the highway. Read what I did on page 2 of this thread: http://www.naxja.org/forum/showthread.php?t=1069391&page=2&highlight=mileage
I still have the LED panel attached and am thinking of connecting it to the dimmer circuit.
 
After reading this thread again, the problems you list still sound like what I had with my '96 when the Throttle Position Sensor took a dump. You claim to have changed it, with a used unit. I swapped new and used units, over the course of about a year, until I found one it was happy with. A used one, with over 150k miles on it. Go figure!

What it was doing was revving, then stalling while stopped at a light, not slowing down after removing foot from accelerator, slipping in and of TC lockup on the highway, actually feeling like the tranny was failing.

If nothing else works for you, I would recommend looking at the TPS again.
 
Thanks for the reminder and info!!! I wonder if anyone knows what year they got rid of the separate upper white switch?

Now that you mention it, I do seem to recall the newer brake switch as being threaded, adjustable, and not interchangable with Renix? (Found that out when I went part shopping, year by year, because my 89 had a bastard, non standard brake light switch, and assy (that I had to modify in order to use the standard switch). And now the TC lock up on that one has stopped workiing. On the vacuum dump, I have no idea, I have never had a HO jeep.

MoFo said:
Ecomike,
In our previous threads about this white switch, I said the infamous white switch was eliminated somewhere between 1990 and 2000. At that time this function was integrated into the brake lamp switch. When this was done, the "switch" went from 4 terminals to 6. I just borrowed a copy of the 1993 wiring diagrams to verify the TCU is using the brake lamp switch. It looks like the white switch is probably a RENIX thing that was eliminated by Chrysler when they made all the other significant engineering changes in 1991. I wonder what they did with the vacuum dump?

Dfete1,
If you want to konw what theTCU is doing with the TC, you really need to monitor the output to the lockup solenoid. Get a T pin to backprobe the TCU connector C-14 (TC Lockup). Dress your meter probes so they won't get knocked loose, set your meter on the console, and take it for a ride. If the TC does not lock and unlock as it should, you could have a problem with the brake light signal. Backprobe the TCU at connector C-10 (STOP LT SW) to verify that signal. If you find your TC is not locking, you could pick up a bonus 3 MPG on the highway. Read what I did on page 2 of this thread: http://www.naxja.org/forum/showthread.php?t=1069391&page=2&highlight=mileage
I still have the LED panel attached and am thinking of connecting it to the dimmer circuit.
Click to expand...
 
Well my 91 ran great till i salvaged all the parts off. i have a sensor tester so I will check tps. I guess I will rig up a pressure tester that i can have in the vehicle to check the fuel psi under load. Im gonna go out here and swap brake swithches and see what happens. I will let you know what happens.
 
Dfete1 said:
Well my 91 ran great till i salvaged all the parts off. i have a sensor tester so I will check tps. I guess I will rig up a pressure tester that i can have in the vehicle to check the fuel psi under load. Im gonna go out here and swap brake swithches and see what happens. I will let you know what happens.
Click to expand...

Don't just swap parts and see what happens. You need to collect some data before you do anything! Otherwise, you are only guessing and will have no way to prove you fixed it. You may be working with a marginal switch adjustment and change the symptom if you bump it. Don't buy a part if you don't know it will fix the problem. Please get out the old VTVM and make some voltage chesks before you do anything else.
 
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