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Green Monster

Green Monster

1/2 ton status
Joined
Aug 10, 2013
Posts
328
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Location
Thousand Oaks, CA
It looks like it had a metal line coming off the back, but it's broken now. Attached to the intake manifold, I had to turn it to make room for the new fuel line and when I loosened the bolt, coolant leaked out of the bolt hole. Has a vacuum line running to it, and some kind of movable plunger thing. Do I need it for smog? I've looked at vacuum line diagrams, and when I search for the related parts, I don't see a picture that looks like it with a label. I think it's an early fuel evaporation thermal control valve, but when I search for one for sale for a 76 K5, the pictures look nothing like it. Confused. I know some of you helped me in my previous post about smog equipment, and mentioned the TVS, but I need to know exactly what it is, and how it's supposed to be hooked up so I can find a new one. Thanks!

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Well it's apparent why I have radio silence on this contraption. Took a picture of it to Napa, who tends to be the most knowledgeable around here. He had a 73 and a 78 K5, and he's never seen it. Couldn't find anything like it in his database. Then took the picture to my smog guy. Strike two.....he's never seen it either. He said it's not for smog, so he recommended I remove it and plug the vacuum lines. I'm going to leave it on for now, and have him take a look at it in person when I take the blazer in to get smogged on Monday or Tuesday.
 
What does the plunger part connect to? It's probably thermally activated, but powered by vacuum? We're talking about the object with the light shining on it, right next to the thermostat housing?
 
Blue85 said:
What does the plunger part connect to? It's probably thermally activated, but powered by vacuum? We're talking about the object with the light shining on it, right next to the thermostat housing?
Click to expand...
Correct, the object with the light on it. It attaches to one of the bolts on the thermostat housing. The plunger is not attached to anything, you can just grab that little "nipple" and push it in and out. There are two vacuum lines, and the broken metal line on the other side, opposite of the nipple.
 
That may be an anti run-on valve aka anti-dieseling valve. They were used in the 70's to pull the throttle valve closed after engine shutoff. Only ever seen one intact, and it was on a Olds.
 
Wow, that looks pretty similar to what I have. Vacuum line on mine runs to that "throttle lever actuator". Strange. So can I just ditch it? Would the throttle level actuator go to? Thanks a lot for your insight, much appreciated. I'm in T.O. if you want to go wheeling. Almost done with it. Trying to hook up with K85Octane too, thinking of heading to Gorman.
 
I think Chris is right,though I've never seen a coolant and vacuum operated idle stop solenoid (or anti-dieseling solenoid) before...
CA probably has some one off strange devices we never see up here in New England..
Usually all the thermally controlled devices are controlled by ported vacuum switches in the thermostat housing ,or intake up front on GM V8's..
I have seen a 70's Chevy with a valve something like that on an aftermarket A/C install,the valve boosted the idle speed up a hair when the compressor kicked in..I do not think it went into a water jacket passage though..
 
diesel4me said:
I think Chris is right,though I've never seen a coolant and vacuum operated idle stop solenoid (or anti-dieseling solenoid) before...
CA probably has some one off strange devices we never see up here in New England..
Usually all the thermally controlled devices are controlled by ported vacuum switches in the thermostat housing ,or intake up front on GM V8's..
I have seen a 70's Chevy with a valve something like that on an aftermarket A/C install,the valve boosted the idle speed up a hair when the compressor kicked in..I do not think it went into a water jacket passage though..
Click to expand...
Thanks, supposedly it's an aftermarket add-on. Not sure why someone would install it, but it's not part of the CA smog requirements.
 
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