Hello All:

I am working on getting a vacuum tubing issue corrected on my 1972 small block. On the right side of the carburetor and just above the intake manifold is the TCS Solenoid Valve (GM Part #1114451).  On one end of it there is a plastic tubing connection (approx 1/4") coming out with two nipples for connecting tubing. On the other end is a 2-pronged wiring connector and also what appears to be a short metal tube. My TCS Solenoid has the wiring connected to it but nothing else. Per the Assembly Information Manual, one of the plastic nipples on the TCS Solenoid is supposed to connect back to the vacuum advance on the distributor. The other nipple is supposed to be connected to a connector on the right side of the carburetor (this carb connection currently has tubing going to the cannister that is mounted under the left front fender).  Also the vacuum advance on the distributor currently connects to the front left side of the carburetor (The front left carb connection is the one that is supposed to go to the canister I mentioned above under the left front fender).

I can get that tubing problem corrected but I have a couple of questions.

1. What is the small metal tubing connector for on the same end of the TCS Solenid? The Assembly Information Manual does not show anything. I read something somewhere that seemed to indicate that originally it might have had a gray colored piece of foam glued to it. I want this to be made back to factory original specs.

2. How can I test the existing solenoid to make sure it is working?

Here is a description I found on the internet on the function of the TCS Solenoid Valve.

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Often referred to as T.C.S. Solenoids; these solenoids control vacuum to the distributor vacuum advance unit. The solenoid determines when and how much vacuum to release. Typically a vacuum line from the carburetor enters the solenoid and another vacuum line exits the solenoid to the distributor vacuum advance unit (some applications have multiple inlet and outlet lines). The solenoids also rely on an electrical signal provided by other T.C.S. system switches/senders via an electrical connection on the back or side of the solenoid (the Engine Harness or T.C.S. Harness plugs into this connection).
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The metal neeple should indeed have a small square of foam..it is a filter for the solenoid.
To test the solenoid, simply apply 12v and a ground to the terminals. You should be able to hear it click. To test it for open/closing, blow thru it with your mouth, or with compressed air. It should be blocked without 12v, and open with 12v.

Also...that solenoid works on a 30 second delay, IF the system is working properly. Once you shift into 3rd, or 4th, it takes about 30 seconds before the solenoid will actually open, and allow vac. to the dist. advance.

The way we check them when doing Ops Judging(NCRS) is to put the shifter in 3rd(engine running), and wait 30 seconds. The engine RPM will rise once the solenoid opens.Adams' Apple2008-03-30 14:50:43

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Joel Adams
C3VR Lifetime Member #56    
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Thanks Joel.  Sounds like the NCRS test you described is based on a standard transmission? Mine is an automatic tranny.  How do you test that?