'71 C10 Fast Idle Solenoid - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BigRed76 · 04-08-2012, 09:44 PM

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 · 04-08-2012, 10:43 PM

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

BigRed76 · 04-10-2012, 01:55 AM

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

DT1 · 04-10-2012, 10:09 AM

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 · 04-10-2012, 06:03 PM

^^^ 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 · 04-10-2012, 07:29 PM

Quote:

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 · 04-10-2012, 10:56 PM

Quote:

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 · 04-11-2012, 09:46 AM

lol

RexDodge · 04-11-2012, 09:56 AM

Quote:

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.

04-08-2012, 09:44 PM	#1
BigRed76 Registered User Join Date: Jan 2010 Location: Loveland, CO Posts: 1,921	'71 C10 Fast Idle Solenoid 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? Attached Images __________________ Zach 1970 Chevrolet Custom Camper K20 1971 GMC Super K2500, 12V/NV4500 swap in progress 1971 Chevrolet Custom C10 1972 Chevrolet Custom Deluxe C20, 5.3/4L60E 1972 Oldsmobile Cutlass Supreme, 455/TH400, 3.73 posi 2004 GMC Sierra 2500HD, LB7/Allison, CCSB 2005 GMC Sierra 1500, 5.3/4L60E, CCSB

04-08-2012, 10:43 PM	#2
Sport/Truck Sierra Grande Club Join Date: Jan 2007 Location: New Mexico USA Posts: 2,433	Re: '71 C10 Fast Idle Solenoid I think its the TCS solenoid, most remove it as it's not used/needed. __________________ 1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe.

04-10-2012, 01:55 AM	#3
BigRed76 Registered User Join Date: Jan 2010 Location: Loveland, CO Posts: 1,921	Re: '71 C10 Fast Idle Solenoid Ok. I dont think its worth trying to make it work right, but thought maybe somebody would have some insight on it. __________________ Zach 1970 Chevrolet Custom Camper K20 1971 GMC Super K2500, 12V/NV4500 swap in progress 1971 Chevrolet Custom C10 1972 Chevrolet Custom Deluxe C20, 5.3/4L60E 1972 Oldsmobile Cutlass Supreme, 455/TH400, 3.73 posi 2004 GMC Sierra 2500HD, LB7/Allison, CCSB 2005 GMC Sierra 1500, 5.3/4L60E, CCSB

04-10-2012, 10:09 AM	#4
DT1 Registered User Join Date: Oct 2009 Location: Gardnerville Nv No Mo Cali!! Posts: 869	Re: '71 C10 Fast Idle Solenoid 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.

04-10-2012, 06:03 PM	#5
dznucks Registered User Join Date: Feb 2006 Location: Smyrna, Ga Posts: 1,647	Re: '71 C10 Fast Idle Solenoid ^^^ 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

04-11-2012, 09:46 AM	#8
Indyuke Registered User Join Date: Feb 2008 Location: Lake Stevens, WA Posts: 623	Re: '71 C10 Fast Idle Solenoid lol



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