Jstan2014

Hello All,
I’m posting this for a fellow Forum member who needs help identifying a cylindrical part under the hood on the right side of the engine, but not attached to anything. The car is a 1972 Coupe 350 with a 4spd. I’m posting two pics and I’ve circled the part in question. It’s also an A/C car with what looks like an aftermarket compressor. Maybe the mystery part is a part of the original A/C? So, who knows what this is and what it does or used to do? Thanks!

What is this?

What is this?

NativeAz

Looks like the transmission control spark solenoid...

Did a quick search for a diagram and found some on autozone site:

https://www.autozone.com/repairguide...00c152800836b0

BLUE1972

part of the Emission system. controlled when the Dissy could get Vacuum.

Called a T.C.S. Solenoid Valve

71 Green 454

From Alan 71, the C3 Guru:

[QUOTE=Alan 71;1574865664]Hi Rick,
Here's a photo of a base 72 engine.
1 small hose from the vapor canister to a nipple on the front of the carb.
1 large hose from the vapor canister to the pvc valve and then to a nipple on the front of the carb.
1 small hose from the distributor can to the TCS solenoid and then to a nipple on the side of the carburetor. The third port on the solenoid has a small foam filter on it.
Hope this helps!
Regards,
Alan

Jstan2014

Thanks for the info guys. I’ve searched the “TCS Solenoid” and see that the car can run fine without it. This would explain why his is unconnected and he’s having no problems that I’m aware of. Thanks again!

fastimes

I have a 72 also, mine is sitting there disconnect too, as is my vapor canister. When I replace my carb, I may try to get everything connected again.

Jstan2014

Our ‘72 Coupe doesn’t have one either, but if I read correctly, the auto cars didn’t have them anyway.

‘72 Base Coupe 350 Auto.

BLUE1972

It prevented Vacuum from reaching the distributor under certain conditions like a cold motor. There were relay on the firewall approx. between the wiper motor and master cylinder as part of the emissions system. All part of the emissions system. (per the Gm books)

Automatics had them and also had a trans switch to control the Dissy Vacuum vie the Solenoid .


There was also an Idle stop solenoid to stop dieseling upon shut off, that was part of the system.

The temperature sender / switch was on the passenger side head on the Small Block for the system.

You can look up the TCS system. I just checked the GM service manual, it's very clear in the Emissions section.

Jstan2014

Thanks again for the help. Forum member Pats67copo also sends his thanks for the responses regarding his engine.

F4Gary

Other than making your car look factory, it is a worthless piece of junk.