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I'm trying to make sure the lines/hoses are routed correctly from the intake/carb/distributer/air cleaner/vacuum switch. Anyone have pictures of this?
I have 1 of 2 hoses from air cleaner that doesn't go anywhere.The middle of the three hose connectors on the vacuum switch is capped...from everything I see that is supposed to go to the distributer advance. The advance line from distributor is T'ed with one to the manifold and one to the top line of the switch. Something isn't right here???
The air cleaner should have a hose from the actuator on the snorkel to the temp sensor in the air cleaner, and them from there to manifold vacuum. The O.A.I. air cleaner adapter hose should also connect to manifold vacuum. Any port that screws directly into a manifold runner is functionally equivalent.
It sounds like someone has bypassed the TCS system on your car and is instead running the distributor from straight manifold vacuum. Not a bad choice, in my opinion. If you want it to be original. the thermal vacuum switch has four vacuum ports. Of the three on the side of the TVS, the bottom one goes to manifold vacuum, the center one goes to the distributor, and the top one is a vent that goes to the back of the carb air horn. The fourth port on the very top of the valve goes to ported vacuum on the front of the carb. This diagram is in your Chassis Service Manual.
in the above picture on the vacuum switch the lower/lowest hose tees off , where does the hose go to? looks like one end goes to the brass fitting on the manifold right in front of the carb but the other end it doesn't show where it goes. Then behind the carb right now I have a larger brass fitting that is T'ed into the distributer advance. what is that supposed to go to if I remove the tee in the line?
in the above picture on the vacuum switch the lower/lowest hose tees off , where does the hose go to? looks like one end goes to the brass fitting on the manifold right in front of the carb but the other end it doesn't show where it goes.
It's just a manifold vacuum source. One end goes to the fitting in the manifold runner. The "unconnected" end simply goes to whatever other devices or accessories on the car require manifold vacuum. Most common is the vac modulator on the automatic trans. It could also serve as a vac source for A/C or cruise, for example. It's just a source for manifold vacuum.
Then behind the carb right now I have a larger brass fitting that is T'ed into the distributer advance. what is that supposed to go to if I remove the tee in the line?
Again, this is just a manifold vacuum source. It's not magic. If your car doesn't require it, cap it. It might be used for A/C, power brakes, vacuum door locks, vacuum trunk release, whatever.
Hum...I'm thinking the vacuum hoses are not routed correctly to the vacuum switch and that's maybe why the trans kick down isn't working?
Trans kickdown has nothing to do with vacuum. The TH400 uses an electric solenoid valve for kickdown. The only vacuum is for the vacuum modulator, and that controls UPSHIFTS, not downshifts.
This is the top electrical connector on the vacuum switch.
Then what does the electrical plug thing on this do? I also just installed new kickdown switch on at the gas pedal. No kick down so I was hoping or thinking it was this and that's when I noticed hoses don't appear to be installed correctly....
This is the top electrical connector on the vacuum switch.
Then what does the electrical plug thing on this do?
The first photo you posted has a whole section in it titled "Operation"...
This is part of the Transmission Controlled Spark (TCS) system. TCS was an early emissions control system to eliminate vacuum advance when transmission was not in top gear to reduce NOx emissions. The electrical connection is connected to a pressure switch on the trans that turns the system off when the trans shifts into third. The rest of that valve is a thermal vacuum switch. Normally the distributor used ported vacuum from the carb. The switch provided full manifold vac to the distributor when coolant temps exceed 210 or so. As I pointed out above, many people (including, apparently, a previous owner of your car) bypassed this system and ran the distributor directly from manifold vacuum. Unless you care about an optically correct restoration, the use of straight manifold vacuum is probably a better choice both for performance and to prevent overheating at idle. This is in no way related to the transmission kickdown EXCEPT where the two wires (kickdown and TCS) share a common connector at the transmission case. If that connector is not in place, the kickdown won't be working either.
I also just installed new kickdown switch on at the gas pedal. No kick down so I was hoping or thinking it was this and that's when I noticed hoses don't appear to be installed correctly....
Have you verified that there is power to the switch? That you get power to the connector on the trans when the pedal is floored? That you can hear the solenoid in the trans click?
Joe, thanks for the info on the distributor vacuum switch, very helpful. Instead of using the DVCS, you mentioned running manifold vacuum direct to distributor, is that better than ported vacuum? What are the advantages/disadvantages? Thanks! Roqetman.
July 11th, 2017, 09:06 AM
