'71 C10 Fast Idle Solenoid

[BigRed76]

On the right side of this picture is what I know as a fast idle solenoid. I know that when its plugged in it works, but it never shuts off to allow normal idle. I also noticed that there are two vacuum ports on the side of it that are not connected. Does anyone know how these are supposed to operate? Or is it not worth my time to mess with it?

[Sport/Truck]

I think its the TCS solenoid, most remove it as it's not used/needed.

[BigRed76]

Ok. I dont think its worth trying to make it work right, but thought maybe somebody would have some insight on it.

[DT1]

I always thought it was an anti dieseling solenoid that completely closes the primary throttle plates when the engine is shut down.
I actually re-wired mine to the A/C switch so it will slightly bump the idle up only when the air is on.
Since you don't have A/C, it wouldn't hurt to remove it.

[dznucks]

^^^ I agree. if you want to run it, set your idle speed with it hooked up.

The fast idle solenoid can be hooked up to increase rpm when a/c compressor is on or used for anti-dieseling

[Autoblueprint]

Originally Posted by BigRed76

On the right side of this picture is what I know as a fast idle solenoid. I know that when its plugged in it works, but it never shuts off to allow normal idle. I also noticed that there are two vacuum ports on the side of it that are not connected. Does anyone know how these are supposed to operate? Or is it not worth my time to mess with it?

It is called a C.E.C. ( Combination Emission Control ) valve and a complete explaination ( three paragraphs ) of it's function can be found in Section 6T of the 1971 Factory Service Manual.

The lower vacuum port connects to manifold vacuum and the upper port connects to the vacuum advance on the distributor.

One of the electrical connections connects to the water temp. switch which is wired through a 15 second time delay relay and the other connection is wired to the transmission switch and is wired to a reversing relay.

According to the service manual if the C.E.C. does not function it will result in no vacuum advance and no high gear deceleration position of the carb.

Again I urge any one who owns one of these trucks to purchase the factory service manual...it is an invaluable tool to help one figure things out.

[Sport/Truck]

Originally Posted by Autoblueprint

It is called a C.E.C. ( Combination Emission Control ) valve and a complete explaination ( three paragraphs ) of it's function can be found in Section 6T of the 1971 Factory Service Manual.

The lower vacuum port connects to manifold vacuum and the upper port connects to the vacuum advance on the distributor.

One of the electrical connections connects to the water temp. switch which is wired through a 15 second time delay relay and the other connection is wired to the transmission switch and is wired to a reversing relay.

According to the service manual if the C.E.C. does not function it will result in no vacuum advance and no high gear deceleration position of the carb.

Again I urge any one who owns one of these trucks to purchase the factory service manual...it is an invaluable tool to help one figure things out.

I find it easier to just remove things I don't understand.

[Indyuke]

lol

[RexDodge]

Originally Posted by Autoblueprint

It is called a C.E.C. ( Combination Emission Control ) valve and a complete explaination ( three paragraphs ) of it's function can be found in Section 6T of the 1971 Factory Service Manual.

The lower vacuum port connects to manifold vacuum and the upper port connects to the vacuum advance on the distributor.

One of the electrical connections connects to the water temp. switch which is wired through a 15 second time delay relay and the other connection is wired to the transmission switch and is wired to a reversing relay.

According to the service manual if the C.E.C. does not function it will result in no vacuum advance and no high gear deceleration position of the carb.

Again I urge any one who owns one of these trucks to purchase the factory service manual...it is an invaluable tool to help one figure things out.

Wow. Nice explanation and I second the manual advice.