Hey guys, I'm about to get my 86 trans am with a carb'd 305 up and running but I'm stuck on the last part of the vacuum diagram! The previous owner threw out the original air cleaner, and I supposedly have a temp sensor and "vac motor" on that. Some say the temp sensor is electrical, but I don't have a connector left over. I've also seen a temp sensor with no electrical connection, but with 2 vacuum nipples. Can someone tell me what is suppose to be there, and maybe some advice as to how to get it back to stock? Thanks!

 

That "temp sensor" is actually a "thermal vacuum switch"... if the temp is below some threshold, the switch is open, and it allows vacuum to pass; if the temp is above, it closes off. It sends vacuum to a vacuum motor (diaphragm) on the stock air cleaner snorkel, that closes a little door, that makes all the air come through the 2" or so sheet-metal hose that goes down to the exhaust manifold.

Depending on where you live, you may have to have every bit of that installed and operating, to pass inspection.

 

The sensor thing is vacuum actuated to open a flap in the intake tube that lets preheated air from the stove below around the exhaust manifold help warm the engine with the warmer air. Unless you are stuck in California or somewhere that the smog gremlins will give you trouble over it not being there
you really don't need it all that much. You will need a stock air cleaner to be able to put that back together if you want to. Still some in JYs.
Have fun with your car, Henry

 

Not meaning in any way to vary from Sofa's post, he just types faster than me...

 

Thanks for the replies guys! So just to be clear, it's nothing electrical? Just vacuum. And no California, no emissions at all!

 

Keyboard on performance-enhancing drugs (REAL STRONG black coffee)

 

Do any of you know who carrys the purge tvs? Mine has broke. You guys are awesome by the way, everyone on this forum really

 

Pretty sure most all the parts stores have those...

 

They have the efe tvs but not the purge tvs. There is a visual difference, but technically speaking, I don't know if they are the same or not

 

They're not the same. Opposite function hot vs. cold, different temp point.

Try a better auto parts store. Not sure you can get the oddball stuff like this at the usual chain stores. NAPA, maybe. I shop at a local joint where real mechanics get their parts.

 

Thanks for the reply! If you know of anything online, let me know. Trying to get this car running in 3 weeks for a 3 hour drive, this is one of the last things stopping that from happening