I have a 1970 442 with auto & A/C. When I tromp on the gas the 4 barrel Quadrajet will not open the secondaries. With the car in the driveway the four barrel opens
fine if I push the gas. The transmission also will not kick down when driving. Would the trans not down shifting cause the four barrel not to open? Many years ago I disconnected & removed
the Transmission controlled spark solenoid on the intake manifold & re-routed the vacuum hoses. I checked the electric downshift switch on the gas pedal. It delivers 11.6 volts to the plug on the side of the
transmission. I can here the solenoid in the trans click. Also years ago the transmission was changed to a later model. I thick it's about a 1974. This transmission has only one
blade in the plug. The connector has openings for two blades. Is there a connection between all of these things not working? Recently I connected the two green wires that went
to the TCS solenoid together. should these not be connected if not in use? This changed nothing. I'm sorry for dumping all this information on you. I hope it's not to much. I don't know what to try next.
his car was scary fast back when It down shifted & had full four barrel. Thank you all for your help.

 

Ok, the quadrajet is probably fine. Its mechanical throttle linkage is probably fine, and the mechanical secondaries are probably opening just fine. The reason there is no punch is because the quadrajet has air horn vacuum controlled air valves which are not opening like you want to feel in the seat of the pants because the engine is not demanding it to do so because it is not downshifting.

First test. Go for a drive. Cruise at 50. Downshift to second via shifter. Bury it. Shift to high on shifter near redline. See if that is the performance you remember. If so, engine is fine.

Now, for tranmission. There are two electrical things on a TH400 of that vintage. Kickdown solenoid and TCS solenoid. Make sure the right solenoid is receiving power. TCS is a stupid system, leave it disconnected. I think ti was still there in 74, so I THINK that trans has two solenoids. Sounds like root of issue is kickdown is not working internal to trans.

 

You may want to reset your kick-down switch above the gas pedal. Push the plastic arm(tube shaped) towards the firewall, push at the base of the tube next to the switch so you don't break it off, you'll hear a clicking sound & it will stay all the way forward. The next time you drive it when you"put it to the wood" it will set itself. Also you can check it while you're driving by getting up to a speed that's in 3rd, reach under the dash or have a pass do it & slide & hold the kickdown arm to towards the rear of the car. If the solenoid is working ok it will downshift.

 

Thank you for the great info. I will try all of those ideas,