Vehicle Emission Control Decal

[81-F150-Explorer]

Using the picture part of the decal actually.

It shows the hose routing, to the PVS (marked VCV on your sticker).  Engine cold or normal operating temp the PVS opens the vacuum advance through the "V-Rest" AKA: Vacuum Restrictor. Engine overheating it switches vacuum direct, bypassing the "V-Rest".

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As for the adjustment procedures, I would follow the directions on the decal.

And yes the idle RPM on the decal is what you should aim for.

With Manual Transmission, With TSP off,  RPM target 525.

With Manual Transmission, without TSP, RPM target 800.

[BigBrother-84]

81-F150-Explorer wrote

With Manual Transmission, With TSP off, RPM target 525. With Manual Transmission, without TSP, RPM target 800.

Ralph, the original carb had such a TSP, but the replacement one doesn’t. So now Big Bro’s idle speed should follow the "without TSP" indication?

[81-F150-Explorer]

Yes, adjust it for without the TSP.

Then you can "tweak" it for the best idle from there, if needed.

[BigBrother-84]

Guys, I am still waiting for the Black PVS (supposed to arrive next week), so Big Bro is running with the Green one.  Better than nothing.

Yesterday was the first long ride (2 hours highway) since this “Ignition Advance Vacuum” setup is back in the truck… and  I’m wondering about the fuel consumption.

Usually takes about half tank from house to chalet (read on the fuel gauge).
This time it took just a little over one quarter.

So I filled up, took note of the mileage, and I’m going to make a precise monitoring.

But is it possible that the difference between running highways without or with Ignition Advance can make a so huge difference?

[ArdWrknTrk]

Yes, of course!
Power and efficiency is the whole point of vacuum advance

[Gary Lewis]

Yes, it is not only possible it is a given that vacuum advance will dramatically help MPG.  (Or is that KPL?)

In fact, that's exactly why vacuum advance was dreamed up.  At high vacuum the engine is not doing a lot of work so can accommodate a lot of advance w/o pinging.  But as you open the throttle the vacuum drops and so does the advance - until it eventually gets back to only the initial advance + centrifugal, which is where you were before you started on this quest of getting everything fixed.

But when you calculate MPG don't forget that your odometer is probably not reading correctly due to the gear ratio issue with your drive and driven speedo gears.  So you might want to figure out what your odometer reads over a 10 mile or kilometer stretch in order to get accurate MPG/KPL readings.

[BigBrother-84]

Gary Lewis wrote

(Or is that KPL?)

In fact we say «Liters per 100km», or L/100km.
In Bullnose scale, 10 mpg = 23.52 L/100km.

Gary Lewis wrote

But when you calculate MPG don't forget that your odometer is probably not reading correctly due to the gear ratio issue with your drive and driven speedo gears.

Thanks for reminding me about that, Gary, I was forgetting this important element!

I'll wait for the 16 tooth Driven Gear before monitoring Big Bro's new "Vacuum Ignition Advance" fuel consumption.

[Gary Lewis]

You will be pleasantly surprised at what a difference vacuum advance makes.  And, as Jim said, you should be seeing/feeling an increase in power, mainly under light throttle.