Help with Vacuum routing

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Mar 10, 2005
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Just wondering what the hookup is for the vacuum distributor (two ports). Are they both vacuum (and if they are, from where [throttle, manifold, etc.], or only one vacuum (outermost port). Thanks in advance for your replies.


TM
 
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Nobody is willing to look at their distributor vacuum routing for me?

Please...Pretty Please....?
 

65swb45

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Inboard one hooks up to vacuum advance via thermal switches that delay the signal until engine is warm. Outer is a supplimental advance routed thru the HAC.

Opinions vary on how to hook them up when the emissions equipment is removed.

I run with the school of thought that says run all the advance you can get without predetonation. ;)
 
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The large line goes inside the cab for dry fresh air. The small one goes to the port on the air cleaaner. If your air cleaner doesn't have this there are several neat ways to make one. I just read of one. Try a search. The vacuum line from the vac advance port goes to a port on the passenger side of the base of the carb. My vac retard is plugged.

Good point Mark, I assumed this was de-smogged!
 
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Thanks guys. Yes it is de-smogged (should've noted it above). I am currently running the cap drier line to the valve in the cab with the other hooked to manifold vacuum. On the advance I was only running the outer port to a port below the throttle plate.
 
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Thanks Roverpilot but not much. I am de-smogged and have the dual port vacuum advance. I just wish I would have taken a picture three years ago when I tore this damn thing down. Oh well, thanks anyway.
 

FJ40Jim

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If you have a 12/78-earlier electronic distributor, it is vac advance and vac retard. The outer vac fitting is advance, connect it to ported vac on carb. Inner fitting is retard, connect to nothing.
 
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Thanks Jim- that's the way I have it now. I was just making sure as I have low power under around 1300 rpms.
 

cruiseroutfit

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Seems some people are talking about the vacuum advance on the dizzy, while others are talking about the breathers on the dizzy cap :D

As Jim pointed out, 78' would be vacuum advance and retard, 79' and later would be advance advance, the inner one is ~8 degrees and the outer is 4*, though I have never tested those numbers... :D
 
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cruiseroutfit said:
Seems some people are talking about the vacuum advance on the dizzy, while others are talking about the breathers on the dizzy cap :D

As Jim pointed out, 78' would be vacuum advance and retard, 79' and later would be advance advance, the inner one is ~8 degrees and the outer is 4*, though I have never tested those numbers... :D

Since we are discussing the vacuum ports, I NEED some clarification..I have a (Nov 77 build-date) 78 FJ40 California model. My dizzy CAP has two (breather?)ports, a larger one near the "rear" of the cap, and a smaller one near the "front" of the cap. The larger port is connected, via tube, to a gizmo high in the passenger footwell, maybe a fresh air source, Hell I dunno??? The smaller port is connected to a port on the right side of the factory air cleaner, directly above the dizzy. The vacuum advance mechanism on the side of the dizzy has a vac port that is connected to the black box (emmision control) mounted on the left fender well. NOTHING is connected DIRECTLY to the carb base or intake manifold.

The truck runs well but gets LOUSY (I know, I know) gas mileage, and NO, I aint gonna go buy a bicycle!!

Does this configuration of vacuum lines sound correct? AND do I have a vac advance, retard, or combi dizzy? My vac lines seem to reflect the diagram I posted above, a few days ago..but that diagram doesnt show the two ports on the dizzy cap.

Thanks in advance,

Rob
 
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Joined
Mar 10, 2005
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Thanks for the replies guys. I had it hooked up right (though no retard) and guess I have another problem.
 
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Jim, thanks, but what about the vac advance line running to the black box? At idle, if I unplug the hose, there is no change in engine speed. Also there is no noticeable sucking from the port on the black box. However if I instead hook the dizzy vac line to an obvious vacuum source (carb or manifold port) the engine noticeably slows a bit. My above diagram DOES show the vacuum line connected to the black box. Comments? Thanks, Rob
 

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