weird transmission issue (1 Viewer)

[Thatguythesecond]

So on my 94 FJ80, i spent today installing a new mass air flow sensor, and getting my truck to learn its idle, i ended up having to recenter my tps to get it to re-learn the idle after wards. I only set the tps so that the idle switch turns on when the throttle is shut. before you judge me for that, it looked like someone had adjusted the tps in the past and it was all the way at one end. so here is my problem cruiser idles properly with no cel for the first time since I bought it. Now when I start it and put it into drive it tries to start out in ether third or fourth, i can't tell wich, if i shift it into L then back to drive it will shift normally until the next time i put it in park. help!!!

thanks
Jeff

 

[Thatguythesecond]

does any one have any ideas even?

 

[dlmcgehee1]

I'm not an expert, but it sounds like an issue with the pump or valve body in the transmission.

 

[slow95z]

Mine does the same thing. I just deal with it. With as many miles as I have I feel lucky it even drives.

 

[Wayne]

Did you have ANY transmission problems before you replaced the mass air flow sensor and adjusted the throttle position sensor? Both of those sensors dramatically effect the engines performance, but I don't believe they have any effect on the tranny. I may need to be schooled here myself.

 

[baldilocks]

I know that the TCU receives a signal from the TPS among a few others. I have yet to mess with my TPS so I can't relate to this adjustment that you did and describe as if it was somewhat unorthodox but worked anyway.
You need the 1994 FSM and there is a separate manual for the transmission which goes a little deeper. You can search and find these manuals available right here on Mud along wih tons of personal experiences of the exact nature of your current issue when you use the search function.
Does or has your Over Drive "Off" light flashed steadily while driving? If so, there is a code(s) stored in the TCU waiting to tell you what the problem maybe. If you have codes then your problem is electical and usually fixed with a new shift solenoid or two.

 

[Dave 2000]

Shot entirely in the dark here, is it possible the shift lever/cable is out of sync? Moving through to L and bringing it back puts into D instead of 3 for example? Don't shoot me if that is a ridiculous thought but I have seen it on other automatic vehicles. The diesel automatics have a kick down cable tied in with the throttle cable, do you have that for example and it is now out of sync?

Just throwing a few thoughts out there and giving the thread a bump at the same time.

regards

Dave

 

[Thatguythesecond]

I had no issues with the transmission before i adjusted the tps, i have no warning lights on at all now that i have replaced the maf. My transmission was fine before i messed with this, it is odd since it actually shifts a lot better now.

 

[Wayne]

This is just a wild guess. Since you replaced the mass air flow sensor and adjusted the throttle position sensor, it might be possible the ECM is trying to re-learn and adjust to the new inputs. You said the TPS was fully turned in one direction, so the ECM had to adjust to that input, but you moved it and install a new MAF sensor. Now the ECM don't know what to think....lol. You might give it a day or two to see if it might re-learn and correct itself. Like I said at the beginning, just a wild guess.

 

[Alleycats]

Dude your TPS is out of adjustment. There is an ohm spec for adjusting it in the FSM or you can just mess with it until it shifts right. Those things are sensitive though.