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1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks Discuss the Early Eighties Bullnose Ford Truck

EEC vacuum diagram questions

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Old May 24, 2017 | 09:39 PM
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EEC vacuum diagram questions

While I am waiting on the Holley carburetor gaskets to arrive, I decided to start confirming all the vacuum lines are properly connected. Since I do not have the oem variable venturi carburetor​, I'm trying to figure out which vacuum lines goes where. Behind the carburetor, I've found an uncapped line on the 4 way tee and another vacuum line that loops onto itself connected to the back of the holley carb. I've taken a pic of the vacuum diagram on the radiator support and have a few questions regarding which vacuum line goes where on the carb. From the Does anyone know what the V, C, CM, and BV stand for?
 
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Old May 25, 2017 | 07:50 AM
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I have a listing of the acronyms here: Vacuum Diagrams - ???Gary's Garagemahal. And info on what vacuum lines I think are necessary without emissions controls here: Vacuum Systems - ???Gary's Garagemahal.
 
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Old May 25, 2017 | 09:25 PM
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Originally Posted by Gary Lewis
I have a listing of the acronyms here: Vacuum Diagrams - ???Gary's Garagemahal. And info on what vacuum lines I think are necessary without emissions controls here: Vacuum Systems - ???Gary's Garagemahal.

Great - thank you for taking the time to assemble those pages. It appears I have a few more to add to your glossary once considering the EEC setup. The ones I could not find are:

CM (on passenger side of CARB)
V (rear of CARB)
C (rear of CARB)
TVV (inline vacuum valve on passenger side)

Here is one not yet listed that is spelled out on my sticker:
VOTM : Vacuum Operated Throttle Modulator


So if anyone could help with C, V, and CM...
 
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Old May 25, 2017 | 09:38 PM
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TVV is thermal vent valve, as shown on my page. But I don't know what CM, V, and C are. As for VOTM, I'll add it to my page. Thanks!
 
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Old May 26, 2017 | 07:37 AM
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Those dashed lines are all your evap lines. In other words, they contain and carry fuel fumes to the charcoal canister which is that box in the corner of the diagram with "Fuel T" going to it.

I can't figure what the v and the c are. I was going to say v was venturi vacuum, but why would you tie the v and the c together as they did in the diagram?

As far as the CM, they are hooking manifold vacuum to something external on the carb. That is unusual, since they have manifold vacuum right there under the carb. The times I have seen them hook to a external vacuum source for the carb is the choke pull-off(usually a short hose going right to the bottom of the carb) and I have seen a picture Gary or someone had on here where they hooked a external line to a port that went to the power valve.


I hope the original poster's plan works out but it may not. A smog guy who knows his stuff will be tipped off right away by the distributor with the vacuum advance on it. You can hide a lot of stuff under the original aircleaner, but the dist is hard to hide.
 
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Old May 26, 2017 | 07:55 AM
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Dave - The pic of the external line to the power valve may be the one at the very bottom of the Internal Systems tab here: Motorcraft 2150 - ???Gary's Garagemahal.
 
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Old May 26, 2017 | 08:06 AM
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That's it. Can't get "CM" out of it though. Didn't he say his diagram was for a variable venturi carb? Did they even have power valves? I rebuilt one a long time ago but don't remember much about it.

 
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Old May 26, 2017 | 08:12 AM
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I think he said he doesn't have that dreaded carb. (Never rebuilt one. Was given one once, but never used/tried to use it.)

And I can't find "CM" in any documentation either.
 
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Old May 26, 2017 | 09:17 AM
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Originally Posted by Franklin2
I can't figure what the v and the c are. I was going to say v was venturi vacuum, but why would you tie the v and the c together as they did in the diagram?
My 83 manual shows a "V" as Venturi Vacuum.
 
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Old May 26, 2017 | 09:53 AM
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Originally Posted by Gary Lewis
And I can't find "CM" in any documentation either.
CM might be the same as an ISC - Idle Speed Control.
 
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Old May 26, 2017 | 09:59 AM
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I'll add the V as Venturi to my web page, but hold off a bit on the CM. But, I agree that it looks like The device to slow the throttle's return. However, with manifold vacuum to it I would think it wouldn't do the same thing. Hmmm...
 
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Old May 26, 2017 | 11:01 AM
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Originally Posted by Gary Lewis
But, I agree that it looks like The device to slow the throttle's return. However, with manifold vacuum to it I would think it wouldn't do the same thing. Hmmm...
I'm assuming he has an 82'

FYI;
My 83 book shows a 7200 with the "CM" for a 5.8L

Also shows a 7200 "ISC" in the same location for a different calibration 5.8L.

Glossary only list the "ISC", no "CM".

Zonker; Do you know your Calibration Code?
 
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Old May 26, 2017 | 12:29 PM
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Maybe; decel throttle "control modulator"

See closeup of Dashpot..;

 
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Old May 26, 2017 | 06:00 PM
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If we could get the calibration code we would know every part in the fuel system, so could probably nail down what "CM" is.
 
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Old May 26, 2017 | 08:29 PM
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Originally Posted by Franklin2

That's it. Can't get "CM" out of it though. Didn't he say his diagram was for a variable venturi carb? Did they even have power valves? I rebuilt one a long time ago but don't remember much about it.

The photo shows the 2150 carb. The port on the PV cover is an External Power Valve Vacuum Source (Manifold Vacuum).

The external vacuum nipple must be connected to a manifold vacuum source with a hose.
Source- Motorcraft 2150 2V Carburetor

CM?

I have shop manuals that identify all of these abbreviations but are packed away...
 
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