93jeepthing

Hello all!, for awhile now i have been wanting to get an xj and i finally bought one about a month and a half ago. shortly after buying it it started to have some very erratic shifting- not going into 4th, starting off in 3rd or 4th, or getting stuck in 1st... usually turning on and off the vehicle would temp. fix the problem. After doing a bit of research online i found that there seems to be a lot of issues with the TCU. So i pulled the TCU and found out that it had already been replaced with one out of a '92 xj. After checking the wiring, solinoids, TPS, ect... i decided to replace it again with one out of a '96. Right away the problem was fixed. I then drove it about 3k miles including a 2,400 mile trip to Utah with no problems. A couple days ago it started having identical symptoms as before... and now it will not even shift out of 1st at all, so i unplugged the computer and i shift it manually.
My question is: Does anybody know what makes the computers fail? what are the odds that 2 tcu's in a row are bad? should i put another one in? Any and all info. will be very much appreciated. I love this Jeep, and i had plans to keep it for a very long time... I really want to see it back on the road again.

Thanks,
Brian

cole93maxxxj

I dont know man i have been having that same problem with my 93! i just figured out that my tcm is bad i gotta get a new one because it hauls *** in reverse but in forward its a slug! so i gota replace that! but might just be bad design...

93jeepthing

yeah, sounds like you are starting off in 3rd or 4th. If you still drive it i would be very carefull because you will eventually burn up your transmission... If you have to drive it just unplug the TCU (under the passenger side dash) and shift it manually. You will get your power back, but it will skip 2nd gear. That's better than starting in 3rd or 4th though...

-Brian

Stan6406

Throttle position sensor

93jeepthing

i looked into the TPS, and i checked it both with a scan tool, and with a voltmeter at the TCU connector. It checked out perfect. Do these go bad intermittently? and will they toast a TCU?

thanks,
-Brian