mystery TCS problem

[Jack H.]

Re: Roberto's correct...

If memory serves, the tranny switch is a contact closure to ground that fires the TCS solenoid by giving B+ a current path to flow through. When the solenoid is de-energized, internal spring closes the vac path to the distributor and opens it when the solenoid is energized.

The vac vent connection to the carb is simply a means of allowing vented vac to be from FILTERED air (carb's air filter). Other, similar electro-mechanical vac solenoids simply tacked a piece of foam over the vac nipple to serve as a filter...

[Patrick H.]

Re: Roberto's correct...

Jack,

Agreed, but looking at the 1970 setup, it doesn't seem to work that way. The "closed" path of this solenoid is the opposite of every other solenoid?

I'd like a 70 owner to check their system and let us know.

Patrick

[Dennis D.]

Does this help? *NM*

[Patrick H.]

Re: Does this help?

Dennis,

Yes, I think it does. I'm sure Jack will correct me if I'm wrong (me and electronics don't get along well) but it does seem to confirm that the solenoid is "on" in gears 1 and 2, "off" in 3 and 4, thus allowing vacuum to the distributor in 3 and 4. This on/off sequence is the opposite of a 72 but with the same "vaccum result", which is why I was asking for clarification.

Thank you.

Patrick

[Dennis D.]

Re: Does this help?

Patrick

FWIW I used to have a problem with the TCS relay on the firewall grounding out. In essence de-energizing the system which in turn raised my idle.

So I guess I'm agreeing with your reasoning.

(One electronically challenged to another)