hey guys a buddy of mine brought me his 89 gta this spring to remove the tpi system because he was having problems.and wanted to go carb.
so for the time i just took all the wiring and taped it up as small as i could and left it to the side.as i left the trans part pluged in (i think its 4 wires)
but now he's back and wants me to completely remove the harness and ecu.
can i do this with out damaging the trans ?
would the lock up still work with just the trans pluged in and nothing eles ?
and help on this would be great guys.

thanks

 

The wires to the transmission above the pan do 2 things:
1) Tells the computer when the transmission is in 4th gear
2) The computer tells the transmission when to lock up the torque converter clutch

#1 isn't an issue, since without the TPI, the computer doesn't care about whether or not the transmission is in 4th gear.

#2 is an issue. Without the TCC locking up in cruise conditions, excessive heat will be built up in the transmission. This is usually exhibited by burning up the 3-4 clutch pack. You'll probably notice this first when the transmission will not shift from 2nd to 3rd at wide open throttle. Eventually you'll lose 3rd-up.

You can remove all of the computer wiring by disconnecting it from the computer, unclipping it from the bulkhead connector in the passenger kick panel, and pulling it out of the fenderwell into the engine compartment. You should get a kit that locks up the TCC using a vacuum switch to disconnect the power under low vacuum (power) conditions. The power for the TCC should come from the brake light switch.

The wires at the tailshaft are the vehicle speed sensor, which runs the speedometer. I can't claim sufficient familiarity to tell you if they are part of the ECM harness. I don't think so, but I don't know.

By removing the ECM, you'll also defeat the signal the computer sends to the fuel pump relay to turn on the in-tank electric pump. The oil pressure switch should provide that function, though, after the engine starts. You may have issues starting the car if the carb fuel bowl(s) doesn't have fuel before cranking.

Out of curiosity, how did you hook up the TV cable to the carb? That's another critical function, and if not done properly, again, you'll burn up the transmission.

 

im doing the same except to an LG4 car so I was researching how to wire up the fuel pump relay since I didn't receive any help in my own thread, BUT about the TV cable... if we shift manually 1st through 4th, does the tv cable still affect the trans???

 

Yes. TV stands for "throttle valve". The transmission needs the input from the throttle in order to properly adjust internal pressures. If it "sees" the throttle at idle because no TV is hooked up, the pressures will be low, and even manually shifting, won't be correct for a shift at anything above idle. You'll burn out the tranny.

 

I have a fuel pump on the side of the block.and removed the electric one from the tank so that's no problem.
I got a good cable bracket from another car for the cables and adjusted acordinly.

 

The Vehicle speed sensor (VSS) wires do run through the ECM bulkhead connector at the kick panel but they don't go to the ECM. They go to a speed sensor buffer board, which on my 86 it sits on the ECM bracket. When you remove the ECM harness you will also loose the ground to the VSS buffer board. You will have to run a new ground wire to the VSS buffer board and remove the two wires for the VSS from the ECM bulk head connector and splice them back together. I believe one is yellow and the other is purple but it's been 9 years since I have messed with this on my car.