Desmogged 2F with 2bbl Aisan question (1 Viewer)

[MDH33]

I hope one of you carb gurus can help me out.

I have a 73 FJ40 that has a desmogged '77 2F engine with a '69 2bbl Aisan carb.

I'm trying to figure out if the desmog is set up correctly for this carb. I recently rebuilt it, but it is still running poorly.

The VSV is still in place, and there are four vacuum ports on the carb, 2 drivers side, two passenger side. (plus the PCV line from the insulator block). On the passenger side, one vacuum line from the throttle body goes to the distributer, the other is capped. On the drivers side, one vacuum line goes to the carb diaphragm and the other to the base of the throttle body. Both lines from the driver side of the carb are going into the VSV and there is another line from the manifold to the VSV.

Pics:

drivers side

passenger side

Does this look correct?

 

[Pin_Head]

Can't tell from the pictures.

I would depend on what type of districutor you have and whether it is vacuum advance or retard, but if it is a vacuum advance type the connection looks fine on the engine side.

You don't need any VSV connections with a "desmogged" engine although it might run better under more different circumstances with the VSV electromechanical controls. It is not just about smog.

 

[MDH33]

I attached a pic with some labels describing where these vacuum tubes are going:

Also, it has been equipped with a vacuum advance distributor.

 

[Fast Eddy]

Your VSV is in the way

I can imagine some uber-genious figuring a way to do something cool with the VSV, but in your case it's just half-disconnected. Get rid of it. Your distributor seems connected ok. The charcoal canister should vent near the rim of the carb somewhere, but with the different carb there may not be a fitting for it. You could install one if you're brave, or just vent it into the air cleaner somewhere. Then cap all the other inlets other than the PCV which you also seem satisfied with.

There's a switch on my '78 charcoal canister which needs ignition power so it only vents when the

In your pic the VSV is connected to a gas valve, not directly. You can loop a piece of line between the ports on the GV, or remove it and replace it with a plug.

Someone wrote that they vented the canister through a BVSV so it only vented after the engine was warmed up. I doubt it will matter.

 

[MDH33]

thanks for the suggestions.

I have an extra inlet on the air filter housing that should except the line from the charcoal canister.

So the carb diaphragm doesn't need any kind of vacuum? I can just cap off all the inlets on the carb (except for the distributor), block the gas filter/valve, and it should technically run? Seems too simple. I'll give it a try.

 

[Fast Eddy]

So the carb diaphragm doesn't need any kind of vacuum?

Oops, I think it does and forgot to mention it. Mine has it. I think it will high-idle without it???

 

[MDH33]

So if I'm understanding the suggestions correctly, I should do away with the VSV and connect the choke breaker/carb diaphragm directly to the inlet on the DS base of the carb becasue it will provide full vacuum.

Also, I should plug the gas filter lines on the manifold.

For the distributor, I should should connect the line to upper left inlet on the PS of the carb because it is ported vacuum and not manifold vacuum?

The line from the charcoal canister to the VSV could be connected to the air cleaner housing instead?

 

[Pin_Head]

Choke breaker should see manifold vacuum.

All manifold vacuum connections that don't do anything should be plugged.

Again, it depends on whether you have a vacuum advance or retard distributor. Hooking up a retard distributor to a vacuum adance vacuum is counter productive. Advance should see "ported" vacuum which enters the throttle body just above the throttle plate. Ported vacuum is zero at idle and incereases with increasing air flow in the primary bore. The port in the aluminum casting is too high to be "ported" vacuum.

The charcoal can will be more effective if it is managed by the VSV the way Toyota intended.
It isn't necessary, but your truck may stink of gasoline.

 

[MDH33]

Choke breaker should see manifold vacuum.

All manifold vacuum connections that don't do anything should be plugged.

Again, it depends on whether you have a vacuum advance or retard distributor. Hooking up a retard distributor to a vacuum adance vacuum is counter productive. Advance should see "ported" vacuum which enters the throttle body just above the throttle plate. Ported vacuum is zero at idle and incereases with increasing air flow in the primary bore. The port in the aluminum casting is too high to be "ported" vacuum.

The charcoal can will be more effective if it is managed by the VSV the way Toyota intended.
It isn't necessary, but your truck may stink of gasoline.

Yes, it has a non-usa spec vacuum advance distributor. I'm going to leave it connected to the PS throttle body as-is. I'll try running a vacuum line from the choke breaker to the other inlet on the DS throttle body and plug everything else.

The charcoal canister re-routing shouldn't be too much of an issue since my 40 already smells like gas.

Thanks! I'll let you know how it runs.