Ported vacuum switch causing problems?

[Hop-up]

I never really gave it a second thought, but my ported vacuum switch ( on the thermo housing) is not hooked up. I just got my chilton manual yesterday and havent had the chance to go out and check my lines, but could this switch ( since its just there with no hoses attached) cause a rough idle ? I think its temp. sensitive, right? So once thye engine warms up, the switch opens, therefore a vacuum leak?

oh

 

[pauly383]

With no hoses on it , it can't cause a leak .

One of the hoses has to supply it vacuum , and the other hoses go to the devices that need vacuum .

No hoses = no vacuum supply .

 

[Hop-up]

Alright i get it. Another thing -

There are two small units on my firewall, maybe 3 inches long. Shaped like a small cylinder. One end has a hose barb, the toher has wires going intot he firewall/wiring harness. There's no lines attached to either of them, there was a tiny bit of hose on the drivers side one, but it has basically rotted away and i don't know where the other end went.

I got a chilton manual for it, but im having trouble identifying these things with the vacuum diagrams. Maybe they're not in there?

Anyways, ill post a photo of them wheni get home, but im hoping these things are part of my rough idle/dies and wont start after 15 minutes of driving problem..

The P.O. also added soem holley valve covers, there's no PCV valve on it, he just had a rag stuffed in its hole. I'm guessing i should get one, could it be yet another culprit of my problem?

 

[pauly383]

Yes you need a PCV valve , and a a breather for air to get into the motor , this of course allows the motor to burn the fumes , but more importantly reduces the crankcase pressure and allows less oil leaks .

One of those switches with vacuum and electrical is for the overdrive transmission , the other I forget what its for , and my Blazer isn't here for me to look at the emissions label either .

 

[dyeager535]

I'm thinking the other is for ESC? (Electronic Spark Control)

 

[Hop-up]

OK that makes sense. There's a broken elbow off of this other unit, it looks like a vacuum fitting. its on the box where my speedo cable goes? here's pics

 

[pauly383]

That box where speedo is is your cruise control unit .

 

[dyeager535]

Just put your finger over the broken off fitting while the truck is idling and warm. Not sure if cruise was ever controlled based on engine temp, but regardless, if that broken piece is sucking air, you've got a vacuum leak.

x2 the box is the cruise control transducer. Bad setup IMO.