Why no kickdown on 7mgte auto?

Alan,the only tps inputs,are thru the wires I had you tap into.If those are all in the correct place,should be fine,unless something alse happened during install.
Unplug the trans ECU,drive it,manual shift thru the gears,for a mile or so.Then plug it back in and see what happens.Had a similar problem with a Corolla fx16,dealer installed a used trans,wanted a warranty replacement.I went up,drove it,did an ECU diagnostic run,worked fine afterwards.
Stay in touch,glad to help if I can.

AlanG said:

I have about 400 miles on my automatic 7mgte converted 85. I can't get the thing to kick down. We have adjusted the kickdown cable back and forth. But it can switch between OD and 3rd using the switch.

In normal driving, from a stop the car goes to 2k rpm and pretty much stays there from 20 mph to 50-55mph. (almost Like a continuously variable transmission). This makes it feel like it may not be locking up.

What might we check out? Is there anything with the trans that might have been forgotten in the removal from the 5m to the 7m? Are there any throttle position sensor/ trans ECU issues?

AlanG

Click to expand...

Are you running the auto trans from the 5m or the 7m? If from the 7m, I think that is electronic and would require the auto ECU to be fully wired up? I don't know too much about auto's, so I have no idea whether I'm even close to what could be the problem, but hopefully it might help

I drove my 84 automatic and it seems clear that the 85 tranny is both not kicking down as well as not locking up. I will be trying the trans ECU unplug and replug later today.
I remember an engine swap on my 86 cressida after which the tranny in drive position would start out in 3rd gear. It would only manually go through the gears. I seem to recall that some or all of the gauges didn't work. Turned out that there was a bad fuse that was marked "gauge" or something else, but it unexpectedly controlled the Transmission ECU as well. Voila, took care of the shift and gauge problem.
In my 84 TSRM I can't seem to find what fuse would do this job. Does anyone know? If I can find this fuse, couldn't I just unplug it to do the ecu reset instead of directly unplugging the ecu?

AlanG

Alan,I'll look into it more this evening.Have a busy day scheduled,so I'll get back too you later.

Does anyone know what fuse or link connects to the transmission ECU?

On my 86 cressida it was the "gauge" fuse and unmarked on the kick panel door as related to the auto trans.

Allen,the best I can tell,the kick down has no electrical,just the cable.I'm still reading as I have time,just been very busy with family,or too much beer to comprehend :roll:
I haven't forgotten you,still working/thinking on it.

I think your throttle cable might need replacement. Once for me it was the 5mge ect computer.

I tried the unplug of the trans ECU. It had no apparent effect.

How does the trans operate the Lockup process? is it mechanical or ECU controlled. Does the speed sensor have anything to do with it?

Is the kickdown controlled entirely by the Cable?

Just sent you an e-mail before I came back in here tonight.Yes,the speed sensor could be the problem.Get back to me via that eamil.

Well we have tried the Tranny ECU reset procedure. My wrench has checked out SOME of the Electrical tests found in the TSRM auto trans section. No change. Right now it is sitting at his buddy's trans shop for a diagnosis.
Does anyone have an idea about what common cause might/could/would trigger both a lack of lockup and lack of kickdown?????

i don't htink it's lack of lockup. i think your in a high gear(3rd or something) and the constant 2k is the torque converter stalling til the output shaft speed makes a difference enough to make the engine speed go higher. have you tried manually shifting thru the gears? going into second won't prove anything. try putting it in first. if that works you prolly have a hydraulic problem.

oh and the throttle linkage that goes to the transmission only changes line pressure(quality of the shift). where the engine shifts is determined electronicly.

Lockup and shift are two different things-Does it shift manually between 1-2 and 2-3? O/D Button is an Electronic lockout of overdrive, so we know you have 3-4 shift-Lockup at converter is controlled by VSS changing signal to ECT to change hydraulic pressure at TC so the clutch inside can move into its locked position-Lockup can occur in any gear, even at a stop, when signal is incorrect-If you have all 4 gears manually, youre chasing a signal prob- Good Luck? Mike

yes, and if it's not shifting it could stay at 2k until about 55 like you said but if it's just not locking up it'd revv the engine much higher before it shifted but it wouldn't stay at 2k. that thing must accelerate dog slow

Mike,this is the trans we talked about at the shop,and I showed you the diagrahms on. :?

Yeah, I wondered about that-Just thinking out loud, trying to remember how lockup worked on that transmission -Still think somehow that speed sensor signal is compromised-But, dont want to muddy waters anymore than they are-Mike

VICTORY or at least mystery solved. Wow what a difference when the car drives the way it is supposed to.

Anyway the problem was found to be erroneous wiring in connecting the engine harness pins to plug B2. They had been connected to the same pins on B1 instead of B2. It was probably a communication problem because those items were verbally transmitted.

So there was no connection for the IDL circuit between the engine and the tranny. A contributing factor is that the engine harness is a manual version and didn't have the IDL wire out of the plug B2 going to the 7m ECU.

Again the car starts properly (had a hard starting problem) shifts normally, locks up and kicks down as normal.

Thanks all for the guidance.

Glad to hear all is working now.Just be nice to it.