90 Auto Trans Problem

[NightmareCB7]

Ive been having a problem with the auto trans in my sedan. It will jump in 2nd at random like its goin into limp mode then pop out back to normal. Some times it just stay in 2nd and some times it will be fine. It mostly does it when the car is up to operating temp and when I let off the gas. It did throw a code 15 when it first started happening but I reset the TCM and now its not giving any codes and still having the trans problem. I have done hours of research and ive already swapped the TCU, shift and lock solenoids and checked the NC and NM speed sensors with no fix. Im wondering if the TPS might have something to do with it. There is no CEL BTW. I do have a spare trans that I can swap into it if I have to but I think its some thing electrical, at least I hope so. I have ran out of ideas so now im asking for help in hopes of an answer.

Heres a video of whats happening, its kinda long.

[Hostile]

Check and maker sure that the throttle body is not lose or the intake manifold.

[NightmareCB7]

Its all tight with new gaskets. I did that when I rebuilt the head not to long ago. I dont have any problems with the engine and its running the best it ever has.

[NightmareCB7]

Bump

[SOHC-FTW]

Tried adjusting your kick down cable? Also examine it for fray's aswell.

[NightmareCB7]

The cable is in good shape and is in adjustment. Thats the first thing I checked when I got the code.

[Raf99]

Wish I could help, I'm stumped though. It's like it's downshifting when you let the gas off a little, would you agree?

Edit: did u see this post? http://www.cb7tuner.com/vbb/showthread.php?t=157237

And when you shift manually does it work?

[NightmareCB7]

Yes it does that most of the time. Its got me so stumped that Im ready to just swap the trans with the old wagon trans.

I did see that one and a few dozen more but still no luck.

Some times it works and some times its just stuck in 2nd. I did notice that when it starts the down shifting thing, Ill get pissed and move the shifter from 1st threw OD and back rapidly and it start working fine for a few secs.

[Raf99]

So you've ruled out the shift solenoid?

[NightmareCB7]

Yep. I tested them and swapped them out. It shifts great when its cold tho.

[cloudasc]

Have you tried taking the cover off your tcu and inspecting it for leaking capacitors?

You should check out this thread: ENG: 90-93 TCU Fix / Preventative Maintence

[danf20bcb7]

Have you tried taking the cover off your tcu and inspecting it for leaking capacitors?

You should check out this thread: ENG: 90-93 TCU Fix / Preventative Maintence

yeah also for giggles find another tcm at the jy and try it.

[cloudasc]

yeah also for giggles find another tcm at the jy and try it.

If its not suffering from problems related to leaking capacitors itself. I highly suggest ANYONE with an Automatic should have their tcu serviced as per the link in my previous post.

Its like turbocharging the stock f22a bottom end, its only a matter of time till you break a ring land; having an automatic transmission is like being turbocharged, and the tcu is the ringland.

^^ Hows that for an analogy

[dysfunk]

This definitely sounds like a TCU issue to me.. I had my TCU rebuilt. I didn't have the tools to do it myself, but I had all the capacitors and resistors replaced and it only cost me 60 bucks.

[cloudasc]

This definitely sounds like a TCU issue to me.. I had my TCU rebuilt. I didn't have the tools to do it myself, but I had all the capacitors and resistors replaced and it only cost me 60 bucks.

You literally had your entire tcu refurbished, it might as well have came off the assembly line in 2011/2012 (or whenever the service was performed)