How does it work? Trans control spark solenoid and switch... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Vic1970 · 08-25-2002, 10:49 PM

Would someone please explain to me how the trans control spark solenoid and trans switch operate... there is a heat switch in there too...

It is on a 1970 GMC C1500 V-8 307 no A/C with A/T (350)

Thanks

Vic 1970

JimKshortstep4x4 · 08-26-2002, 07:53 AM

The system that you are refering to is set up to control the vacuum advance on your distributor. It will let the vacuum advance operate under the following conditions: The transmission has to be in high gear, (manual or automatic) and the engine has to be up to temperature. There is a sensor on the transmission that signals the relay when it is in high gear, also there is a temperature sensor on the engine that signals the relay when the temperature is up. When the relay has these two signals, it will open the vacuum valve and allow vacuum to the vacuum advance. The relay also activates the anti dieseling solonoid on the carburetor.

Jim

Vic1970 · 08-26-2002, 09:51 PM

Thanks Jim...

shadetree · 08-26-2002, 11:54 PM

Yeah, thank you Jim, you're explanation made more sense, and was clearer, and read easier than any in the repair manuals.

JimKshortstep4x4 · 08-27-2002, 06:59 AM

Thanks for the comments. I have always doubted the value of the system as far as reducing emissions, but the systems can really affect the gas mileage and performance on the engines. The effect is to retard the timing under the no vacuum conditions.

Jim

Vic1970 · 08-27-2002, 02:48 PM

Jim,

Again thanks for the great run down on the system... now I have more practical problems ... yes you guessed it ... it is more than one question... here we go...

1. On the solenoid there are three vacuum lines... the one at the back of the solenoid comes from the manifold vacuum port... at the L on the front of the solenoid... how do I run the vacuum lines... one goes to the vacuum advance and one goes to the carb.... but which is which? and the one to the carb connects where? (a book reference the clean air vent... where is that?)

2. Do you have part numbers for the transmission switch, relay, and the temperature override switch... none are listed at the local parts house.

The books only show typical set ups but nothing I can figure out.

I would appreciate any help... all my local experts have a funny look on there face when i talk to them...

I'm hoping you can help... I'm out of gas on this one...

Vic 1970

JimKshortstep4x4 · 08-28-2002, 08:13 AM

Vic,

I will look into your questions and get back to you.

Jim

Vic1970 · 08-28-2002, 11:00 PM

Thanks Jim... and I 'm looking foward to hearing from you... Vic

JimKshortstep4x4 · 08-29-2002, 06:42 AM

I am not having any luck yet on the part numbers, but I have a couple more sources to check out. Anyway the single end tube on the vacuum solonoid is for atmoshere and nothing is connected to it. The hoses connect to the "tee" on the other end. I am not sure which hose connects to which fitting but functionally it would not matter.

I do have a collection of parts if you run into the need, let me know, (jimkemp@iserv.net). 71-72 Chevelles has the same setup
and there are problably other years to look at.

Jim

Vic1970 · 08-29-2002, 05:35 PM

Jim,

Thanks for the response and I appreciate the effort...

Vic 1970

7T1BURB · 08-29-2002, 06:46 PM

Just sent you a PM on the charcoal cannister set-up...BTW if you find out the number for the trans sensing switch, pls forward as ours is busted.....THANKS

7T1BURB

Vic1970 · 08-29-2002, 08:08 PM

7T1BURB

I was able to find one at the local parts store...

Car Quest made... part # PS119 (Switch oil pressure) name on box.

Looks right, plan on using and it the best we could come up with....hope this helps.

Vic 1970

JimKshortstep4x4 · 09-03-2002, 08:07 AM

Here is a site that has parts for the TCS for anyone interested.

www.ss396.com

(Ground up Restorations)

Jim

Vic1970 · 09-03-2002, 06:29 PM

Thanks Jim...

08-25-2002, 10:49 PM	#1
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	How does it work? Trans control spark solenoid and switch... Would someone please explain to me how the trans control spark solenoid and trans switch operate... there is a heat switch in there too... It is on a 1970 GMC C1500 V-8 307 no A/C with A/T (350) Thanks Vic 1970

08-26-2002, 11:54 PM	#4
shadetree Senior Member Join Date: Dec 1999 Location: Knightstown, in, usa Posts: 2,525	Yeah, thank you Jim, you're explanation made more sense, and was clearer, and read easier than any in the repair manuals. __________________ 1970 long fleet, 355 4 speed, primer, walnut goodies

08-27-2002, 02:48 PM	#6
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	yet another question Jim, Again thanks for the great run down on the system... now I have more practical problems ... yes you guessed it ... it is more than one question... here we go... 1. On the solenoid there are three vacuum lines... the one at the back of the solenoid comes from the manifold vacuum port... at the L on the front of the solenoid... how do I run the vacuum lines... one goes to the vacuum advance and one goes to the carb.... but which is which? and the one to the carb connects where? (a book reference the clean air vent... where is that?) 2. Do you have part numbers for the transmission switch, relay, and the temperature override switch... none are listed at the local parts house. The books only show typical set ups but nothing I can figure out. I would appreciate any help... all my local experts have a funny look on there face when i talk to them... I'm hoping you can help... I'm out of gas on this one... Vic 1970

08-26-2002, 07:53 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	The system that you are refering to is set up to control the vacuum advance on your distributor. It will let the vacuum advance operate under the following conditions: The transmission has to be in high gear, (manual or automatic) and the engine has to be up to temperature. There is a sensor on the transmission that signals the relay when it is in high gear, also there is a temperature sensor on the engine that signals the relay when the temperature is up. When the relay has these two signals, it will open the vacuum valve and allow vacuum to the vacuum advance. The relay also activates the anti dieseling solonoid on the carburetor. Jim

08-26-2002, 09:51 PM	#3
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	Thanks Jim...

08-27-2002, 06:59 AM	#5
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Thanks for the comments. I have always doubted the value of the system as far as reducing emissions, but the systems can really affect the gas mileage and performance on the engines. The effect is to retard the timing under the no vacuum conditions. Jim

08-28-2002, 08:13 AM	#7
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Vic, I will look into your questions and get back to you. Jim

08-28-2002, 11:00 PM	#8
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	Thanks Jim... and I 'm looking foward to hearing from you... Vic

08-29-2002, 06:42 AM	#9
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	I am not having any luck yet on the part numbers, but I have a couple more sources to check out. Anyway the single end tube on the vacuum solonoid is for atmoshere and nothing is connected to it. The hoses connect to the "tee" on the other end. I am not sure which hose connects to which fitting but functionally it would not matter. I do have a collection of parts if you run into the need, let me know, (jimkemp@iserv.net). 71-72 Chevelles has the same setup and there are problably other years to look at. Jim

08-29-2002, 05:35 PM	#10
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	Jim, Thanks for the response and I appreciate the effort... Vic 1970

08-29-2002, 06:46 PM	#11
7T1BURB Registered User Join Date: Aug 2002 Location: Newport News, VA Posts: 190	Just sent you a PM on the charcoal cannister set-up...BTW if you find out the number for the trans sensing switch, pls forward as ours is busted.....THANKS 7T1BURB

08-29-2002, 08:08 PM	#12
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	7T1BURB I was able to find one at the local parts store... Car Quest made... part # PS119 (Switch oil pressure) name on box. Looks right, plan on using and it the best we could come up with....hope this helps. Vic 1970

09-03-2002, 08:07 AM	#13
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Here is a site that has parts for the TCS for anyone interested. www.ss396.com (Ground up Restorations) Jim



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09-03-2002, 06:29 PM	#14
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	Thanks Jim...

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