Auto trans problems after ge to gte swap. FIXED

[metaphysico]

I just got done doing a turbo swap but dont have the gte ECT (Trans computer). The car will not go past second gear, I am not sure if it is a problem with the trans or if the ECT is the problem. So the question is will a ge trans computer run a gte trans.

 

[metaphysico]

To add some fun to it the car is also an 88 and the computer and engine are 89up jdm. I have tried both the 88 and 89 ects both for ge and both did the same thing. If anyone has had this problem or seen a ge trans computer work on a gte trans or used a pre 89 computer on 89 trans that information would help

 

[spinyard]

i have used both on the same tranny before and not noticed a difference. but my wiring harness stayed the same (all yellow plug baby!). i think if i were you i would use the one for the 88. check for codes.
also, just out curiosity, did you put the shifter back were its supposed to be?
check for codes here:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=AT&P=13

 

[Nick M]

An electronic controlled transmission for a 7MGE will work on 7MGTE. But it won't last long.

 

[metaphysico]

The shifter is adjusted and no codes. I am going to check the wiring diagrams today to see if there is a difference in the wires for the years. Also what will not last long if you use a ge computer on a gte the computer or the transmission?

 

[metaphysico]

Alright so I have done the driving test and with trans computer unhooked the car will shift properly when manually shifting. I have voltage to the L wire to the ect when its in L, but it does not get voltage on the 2 or the N wires when in their respective gears. I dont see anything that tells when its in drive, I am guessing that when there is no power on N 2 or L it figures its in drive. I am gonna try to swap out the gear selector tomorrow hoping that the problem may be in using the JDM transmission. Does anyone have any ideas what is going on here or have you gone through the diag and can help.
Also there is another strange thing, according to the tsrm the Tt diag port should go from 0-7+ with throttle increase with KOEO, and it does do that, but then it says to test while driving and see if the value changes I am guessing with speed, as it says it should shift into different gears according to the voltage on the port, but I only get change with throttle. So I dont know if something else is supposed to change the value with speed ie speed sensor1 or speed sensor 3.

 

[Nick M]

I said an electronically controlled transmsission will not last long if it is for the GE and used on the GTE engine. The control units are not the same, but they should both work. Speed and gearing are figured into the programming, and that is what is different. The control protocol is the same. I have no comment on products not sold to the US.

Alright so I have done the driving test and with trans computer unhooked the car will shift properly when manually shifting.

Then you do have an electronic control problem. So go into diagnostic mode. Even though you did voltage checks. I should have said there is no voltage when in D. No voltage is the indicator of drive.

 

[metaphysico]

Still havent figured out the problem. I have tried both the aisin and the denso units and neither make any difference, I have also swapped the shift indicator from a usdm auto and that still does not give me voltage in 2 or N on the respective wires in the respective gear. The thing that bothers me is that in all the diag stuff I have seen it says that the voltage on Tt should increase while driving and the shift points are based off of that but I do not see a change in the voltage except with throttle not with speed. In my thinking the voltage should be modified by the speed sensor1 or 2 while driving and this is what should tell the computer when to shift. So if one of these sensors were out it would not send the signal, only I dont have any codes and im pretty sure if either of theses does not send the signal it should have a code. Gonna play with it some more today and see if I can figure it out, if not then later today I am going to swap the transmission out for the ge trans, which I dont really want to do because the clutch packs in the gte are supposed to be better.

 

[Nick M]

If you have a speed sensor problem, it will likely throw a code. Shifting is done with the speed sensor, that is correct. It replaces the govenor valve that forced and upshift. The TPS acts as the throttle valve that delays upshift and forces a downshift. TPS voltage on this car is usually not more than 3.7 volts. You can check it. But low voltage will not prevent an upshift, it will actually allow it and probably sooner.

Remember that your transmission worked fine when unplugged. So I wouldn't want to change transmissions, but fix the control problem.

 

[metaphysico]

Well its finally fixed. After going through the wiring diagrams I found that speed sensor 1 is in the instrument cluster and since the motor was jdm and the speedo cable was on the wrong side and would not fit in the trans I didnt have the speedo cable hooked up. I had to put a dent in the trans tunnel to make the cable fit. Now that its hooked up the transmission shifted fine.

So for anyone with automatic transmissions if your speedo cable breaks you will have problems with the transmission shifting.

 

[Nick M]

Aren't you glad you didn't change transmissions again? That is the point of the test where you drive it unplugged.