700R4 and Transmission Controlled Spark
04-22-2014, 05:50 PM
#1
Instructor
Thread Starter
700R4 and Transmission Controlled Spark
For those that have done a 770R4 swap I have a few questions, this is for a 1972.
There is a TCS solenoid right next to the carb with a hose to the carb from one end and the dist vac advance on the other and then two wires that go to a switch on the TH400 transmission but on the 700R4 that switch no longer exists, so the wires have no place to plug in so do you just remove the solenoid and run the vac line straight from the carb to the dist? IT was broken and glued back together by previous owner so not sure it worked anyway.
Also on the drivers side is an idle stop solenoid that when I replaced the carb with one that allows the use of the throttle control cable does not fit, do I need it?
There is a TCS solenoid right next to the carb with a hose to the carb from one end and the dist vac advance on the other and then two wires that go to a switch on the TH400 transmission but on the 700R4 that switch no longer exists, so the wires have no place to plug in so do you just remove the solenoid and run the vac line straight from the carb to the dist? IT was broken and glued back together by previous owner so not sure it worked anyway.
Also on the drivers side is an idle stop solenoid that when I replaced the carb with one that allows the use of the throttle control cable does not fit, do I need it?
04-23-2014, 12:22 AM
#2
Team Owner
You can leave all of that in place, if you want. Just run the distributor vacuum advance can directly to the manifold vacuum fitting on the right side of your carb. If you want to remove electrical connections to that solenoid, that would be fine, too.
If that stuff needs to be hooked up to pass some emissions requirement in your area, connect it properly when getting tested.
It make it work propely with your 700R4 trans, you will have to find a way to get the trans to trigger a switch when it is in high gear. That will allow the bypassing of that TCS action when the trans is in high gear (as was the original intent).
The 1971 and 1972 Chevrolet Chassis Service Manual has a detailed explanation of the CEC and TCS emissions systems which would be of help to you IF you want to keep them active.
If that stuff needs to be hooked up to pass some emissions requirement in your area, connect it properly when getting tested.
It make it work propely with your 700R4 trans, you will have to find a way to get the trans to trigger a switch when it is in high gear. That will allow the bypassing of that TCS action when the trans is in high gear (as was the original intent).
The 1971 and 1972 Chevrolet Chassis Service Manual has a detailed explanation of the CEC and TCS emissions systems which would be of help to you IF you want to keep them active.