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  #21  
Old 06-17-2011, 04:56 PM
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The HIC valve itself is mounted on the underside of the air cleaner housing just above the distributor. As you can see, it is supposed to introduce a deliberate vacuum leak into the intake manifold via the PCV circuit. This is what the plumbing is supposed to look like:
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  #22  
Old 06-17-2011, 05:07 PM
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So I study the plumbing I have. Holy wrong connections batman! Instead of being connected to the PCV circuit, it goes to the port on top of the distributor cap that is normally supposed to connect to the clean side of the air cleaner housing, which ventilates the inside of the distributor cap!

So what is that VCV that is connected to the PCV circuit for? Why does it have that hose connected to itself?

If I knew exactly what that VCV was for I would have a fighting chance of connecting everything back properly. I know the HIC valve is supposed to connect to that PCV circuit. I know the distributor cap is supposed to connect to the clean side of the air cleaner housing. I am not sure where that vacuum line on the right of the VCV connects to at its other end.
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  #23  
Old 06-17-2011, 05:08 PM
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At first I thought that VCV was for the EVAP system. But then I traced the lines to and from the charcoal canister to this VCV:
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  #24  
Old 06-17-2011, 05:10 PM
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Oh, and as a follow-up, I did measure the vacuum at the vacuum switch with the engine running. I only got about 9". Note that this isn't raw manifold vacuum, it is just below the throttle plates so is somewhat less than full manifold vacuum. When I reduced the idle by closing the throttle plate some I got it up to about 12". Certainly not enough to activate it. And makes me wonder if a valve adjustment might be in order...
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  #25  
Old 06-17-2011, 06:42 PM
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The VCV on the passenger side is for the distributor ventilation - not mentioned in the emissions manual if I recall. The other VCV is part of the canister purge system. The HIC circuit doesn't have a VCV in it. The connection to the PCV circuit is just a vacuum source I thought.

Is the HIC atmosphere port just a vent to let the door in the air cleaner housing return to its default position?
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  #26  
Old 06-17-2011, 07:17 PM
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Jeff, you're welcome to park your 60 next to mine and compare the vacuum spaghetti connections. Mine are stock and properly connected.
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  #27  
Old 06-17-2011, 10:13 PM
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Quote:
Originally Posted by 60wag View Post
The VCV on the passenger side is for the distributor ventilation - not mentioned in the emissions manual if I recall.
Thanks Bruce! That is good to know! It is not mentioned in my manual either. The distributor in my 78 has a much simpler vent system: Hose to the clean side of the air cleaner housing, check valve so gas fumes don't blow up the distributor, hose to the firewall where there is a filter on the inside as inlet for the distributor venting.

I wonder why they would use a VCV instead of a regular check valve like they do on my 78? In any case, clearly this is plumbed wrong, but will correcting it fix my stalling problem? Doubtful IMHO. I still wanna fix it though.

Quote:
Originally Posted by 60wag View Post
The other VCV is part of the canister purge system. The HIC circuit doesn't have a VCV in it.
That is what the manual shows. And as I wrote, I traced the lines and figured out what all that was about.

Quote:
Originally Posted by 60wag View Post
The connection to the PCV circuit is just a vacuum source I thought.
The EVAP system has its own connection to the intake - it is near the top of the carb.

Quote:
Originally Posted by 60wag View Post
Is the HIC atmosphere port just a vent to let the door in the air cleaner housing return to its default position?
No the HIC has it's own port to the clean side of the air cleaner housing. When open, it bleeds air into the manifold as shown in the table according to the air temperature at the HIC. It appears that the source of temperature for the HIC is from the flow from the HAI. I think...

Again, at the end of the day, I can look at so many things that might be right or wrong with this system, but she used to idle just fine before I dorked around with getting her through emissions. I *thought* I put her back the way she was, but clearly something has still changed. I still haven't tried blowing out the bowl of the carb.
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  #28  
Old 06-17-2011, 10:16 PM
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Quote:
Originally Posted by MDH33 View Post
Jeff, you're welcome to park your 60 next to mine and compare the vacuum spaghetti connections. Mine are stock and properly connected.
Thanks Martin, I may take you up on that. Or if you wanted to just snap a couple of pictures that would be helpful?
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  #29  
Old 06-18-2011, 07:48 AM
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Try the "shade tree" carb rebuild. Take the air cleaner off, put a glove on your hand, rev the motor up to about 2,500 rpm, then slam your hand over the bowl of the carb and kill the engine. If you have a little piece of crud in there that got introduced when you changed the jets or added all of the methanol, this could suck it through with the vacuum spike it causes. Nothing to lose by trying and it wont hurt anything.

I did it on my 2F and it fixed a rough idle situation instantly.
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  #30  
Old 06-19-2011, 08:04 PM
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Quote:
Originally Posted by Air Randy View Post
Try the "shade tree" carb rebuild. Take the air cleaner off, put a glove on your hand, rev the motor up to about 2,500 rpm, then slam your hand over the bowl of the carb and kill the engine. If you have a little piece of crud in there that got introduced when you changed the jets or added all of the methanol, this could suck it through with the vacuum spike it causes. Nothing to lose by trying and it wont hurt anything.

I did it on my 2F and it fixed a rough idle situation instantly.
That is a good idea Randy! I am familiar with this, my friends used to call it a Polish carb rebuild

And it would address the question that I keep finding myself going back to: "What has changed"? I may still take off the jet access ports and blow some compressed air into the bowl though. I really don't want to have to take the air horn off the top to access the bowl, there is just so darn much crap on a 60!
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