Desmogged '75 FJ40 vacuum routing help (1 Viewer)

[bentwigg]

I know there are already some good threads on this general topic, but I haven't come across one that seems to cover my exact setup (if you happen to read this and know of an existing thread with answers to my questions, please post a link!). My FJ40 was desmogged by its previous owner, and all remaining vacuum ports were left open or capped, i.e., there wasn't vacuum hose connecting anything. I just had my 2F rebuilt and am now reassembling and wanting to get it "right" (whatever that means without several of the original components!). Here's a list of all the vacuum ports I'm seeing:

• Distributor (stock, semi-electronic): 1 port
• Carburetor (stock Aisan): 3 ports (1 each top, side/base, AAP diaphragm)
• Intake manifold: 4 ports (3 top, 1 side)
• Thermostat housing unit: 2 ports

And here are photos of what I'm referring to (in the order listed above...looks like it's limiting me to five uploads for this post, so I'll try posting a few more in a second post):

 

[bentwigg]

Any advice on (a) what to connect, (b) what to cap, and/or (c) what ports I'm missing would be greatly appreciated - thanks in advance!

 

[1911]

This Jim C.-approved de-smog schematic is for a '79 and later 2F, but much of it will apply to yours also.

The hexagonal fitting with three nipples on top of your intake manifold is what the schematic calls a "gas filter". It is a vacuum source. Only one of the three is used, to supply vacuum for the distributor evacuation system (which your '75 may not have). You ought to cap with rubber or silicone caps, whatever is not used.

the BVSV on your thermostat housing can be used for the charcoal canister evacuation system (again, if your '75 has that).

de-smog schematic

• 1911
• Jan 10, 2018

 

[bentwigg]

This Jim C.-approved de-smog schematic is for a '79 and later 2F, but much of it will apply to yours also.

The hexagonal fitting with three nipples on top of your intake manifold is what the schematic calls a "gas filter". It is a vacuum source. Only one of the three is used, to supply vacuum for the distributor evacuation system (which your '75 may not have). You ought to cap with rubber or silicone caps, whatever is not used.

the BVSV on your thermostat housing can be used for the charcoal canister evacuation system (again, if your '75 has that).

de-smog schematic

• 1911
• Jan 10, 2018

Thanks, 1911, I'll try to compare the schematic to my system tonight and report back...

 

[Pighead]

Perhaps I can help with 1 vacuum line. Your dizzy port traditionally will connect to the port at the base of the carb on the valve cover side.
I'm running a '76 2F block with a '74 1.5 F head and a '69 intake and '74 carb...only have 3 vacuum lines, and 1 is for the brake booster.

 

[subzali]

Pic 1, your distributor is not vented, so the only vacuum line would be from the diaphragm to the carb base as Pighead said.

The port on the front of your carb is the power valve, I believe is connected to manifold vacuum at the gas filter in desmogged rigs.

On the lower front of your carb is a thermo switch, obviously not connected to anything. May be a loose wire somewhere. On the side of the carb base is where your distributor would connect, the AAP I forget what to do when desmogged, I’m sure @FJ40Jim could straighten this all out in a jiffy.

The gas filter I would run one port to the power valve and plug the other two.

The small one on the side of your intake manifold that’s not hooked to the PCV hose needs to be plugged.

The BVSV by your thermostat is not doing anything, you could plug just to keep stuff from getting in there, or remove and replace with OEM plugs. @beno posted a part number somewhere.

Good point above about your charcoal canister, is that installed still?

Good luck!

 

[bentwigg]

Thanks, guys! Forgot about the charcoal canister; here's what I'm seeing come off it (not connected/capped near clutch & brake cylinders):

 

[FJ40Jim]

Connect manifold vac to AAP.
Connect manifold vac to PV at top of carb.
Connect manifold vac to CB (doesn't appear to be there anymore).

Don't connect vacuum to the vacuum retard dissy.

Leave the canister vent hose open to atmosphere on the driver's fender. Stick 1/4" hose & fuel filter on the end of the end of it to keep the water & bugs out.

Cap the big open fitting on the air cleaner lid.

Cruisers were simpler back then, so that about covers it.

 

[bentwigg]

Thanks, @FJ40Jim! CB = choke breaker? And should I leave the dissy port open or cap it?

 

[FJ40Jim]

Yes, choke breaker.

Dissy and BVSV can be left open, they are not leak sources.