Fastbrad

Hello everyone. I just got a 81 a couple of months ago and slowly working through all the issues. The computer is disconnected by former owners and most all the smog stuff is gone. It has a non computer carb. I ditched the stock dizzy that had no advance and put on another one and set it up. It's running really good now but the torque converter doesnt lock up of course because no computer.

I looked at lots of posts but found some conflicting info on how to put a switch in. Right now I would just like to test it with a toggle switch to see if it works and then later add a vacuum switch and connect up the brake switch to the circuit.

I have 3 wires out of a flat connector at the firewall coming up from the tranny. No voltage at the wires with key off but there is voltage with key on at both the outer two wires. The center wire has no voltage with key on or off and no continuity to ground.

So, which wires should I connect to what? I read where I should ground one wire to get the lock up but confused as to which one. Thanks in advance for your help.
Brad

David Mc

I don't have my service information in front of me but I would suspect the three wires are power, ground for the solenoid and input sensor (for third or fourth gear).

Power for the solenoid comes from the brake switch. It sounds like that one is still operational. Have someone step on the brake pedal to confirm.

7T1vette

You can put a simple switch in to turn it on. But, what happens when someone cuts in front of you and you have to do a 'panic' brake apply. If you don't disengage the L/U clutch, it could easily fail. That's why there is programming in the computer to force a disengagement whenever you hit the brakes, stomp on the gas, pull a heavy load, or start up a steep hill. Otherwise, the L/U clutch (which is not designed to handle much torque) must drop out when those conditions are encountered.

I built a little circuit that works for me which has a momentary switch (to cause L/U to engage), a disconnect switch on the brakes, and an auto store relay. When you press the button, L/U engages; when you touch the brake pedal (no need to actually apply the brakes), L/U disengages. The only condition not managed by this circuit is the 'step on the gas/climb the hill' situation where L/U should be disengaged first. With this circuit, you have to do that yourself {by touching the brake pedal}.

If you want a circuit diagram, send me a PM with your e-mail address and I will forward it to you.

Fastbrad

If you want a circuit diagram, send me a PM with your e-mail address and I will forward it to you.[/QUOTE]

PM sent.

So today I noticed that the 3 prong connector was
labeled "A, B, C if that helps.

doorgunner

There are several ways to connect the "lock-up" solenoid inside the transmission.

As the members stated, the best way if the computer has been removed is to:

Install an OFF/ON switch that receives power ONLY WITH THE IGNITION KEY ON......that will allow 12v to go to the solenoid-lock-up-switch on the upper arm of the brake pedal which de-activates the lock-up solenoid when sudden stops are made.....
.then the 12V wire goes to an aftermarket under-dash adjustable vacuum-electric switch which acts like the computer by de-activating the lock-up solenoid when the accelerator is pressed hard.....
then the 12V wire goes to the connector on the side of the transmission to one of the "lettered" terminals (I forget which one/a web-search will help identify the correct terminal)....
another terminal is used as the lock-up solenoid ground wire/search web....
.the 3rd terminal is not used since there is no computer.....

the 4th terminal is a "dud"---no wire is connected to it.

There are easier ways...but they don't work as well....and they can cause the transmission to fail/"burn-up".

Fastbrad

Thanks guys for the great ideas.

Today I did a "test" of what I have currently. I tapped into each of the 3 wires, A B and C and led them back around inside the car. (A and C have voltage with the key on) I went for a ride and got up to operating temperature, then I connected A to B and then C to B and then A to C and then all of them together but nothing happened in any configuration. No lock up. So maybe some part of the computer is working and interfering with the lockup?

Next l will disconnect the 3 pin connector to the firewall and just put voltage and a ground in different configurations to the 3 pin wires going to the tranny to test the system that way. Should I get a click noise from the solenoid in the tranny with the engine off or does the tranny have to be spinning when driving?

JimLentz

Perhaps the torque convertor was swapped out with a non-lockup type.

doorgunner

Jim Lentz has a goodpoint.
I'm thinking you should hear a click/thump if wired correctly with the key ON and engine OFF.......with vacuum applied to the electric-Vacuum-switch in order to activate the switch which sends 12V to the(TCC) lock-up solenoid.

Fastbrad

That's what I was thinking. I should hear the click. I will try again next time the weather is good I have no idea of the history of the car other than the guy I bought it from and what the previous owner told him...not much. These cars seem to go through a lot of owners.
Brad

David Mc

Those solenoids are very quiet. It's submerged in tranny fluid.

80-Vette

Before putting a lot of time and money in the engine I would have a compression test done. The lack of power and miss stands out to me.