1987 FJ60 charcoal canister replacement question (1 Viewer)

[imratz]

I know there are other threads, but I’m have a question that I haven’t found the answer to yet.
On the AC Delco replacement canister, there are three ports on top. The original has three on top and one on the bottom.
This leaves me with one extra port.
I have figured out the intake and purge lines. I have also seen where I can take the 1/2” port to the frame vent, but my question is what to do with the other line? It looks like it comes from the carburetor, but I’m not that smart to be sure. I’m pointing at the extra line. Where does this go??
TIA
Ratz

 

[OSS]

The carburetor float bowl is half way full of fuel at engine shut down. The hot engine cooks it and the fuel then vaporizes and travels.
On a stock 2F engine on the FJ60, there’s a large breather hose connected to a biggish pipe that leads into the float bowl chamber at the top.
That vent hose then leads down to the charcoal canister and is regulated On/Off by the vapor solenoid attached to the original canister. Toyota calls it the Outer Vent Control Valve.

When the engine is off, the solenoid is open, allowing gas fumes to waft down into the canister.
When the ignition key is turned On, the solenoid closes and the vent hose is blocked.

That vent hose needs to go somewhere now with your new canister since it doesn’t have an extra port.

It’s important to vent the float bowl after shutting down to prevent all those gas fumes from entering the air cleaner housing (and migrating to the distributor if it’s VCVis toast).

 

[imratz]

The carburetor float bowl is half way full of fuel at engine shut down. The hot engine cooks it and the fuel then vaporizes and travels.
On a stock 2F engine on the FJ60, there’s a large breather hose connected to a biggish pipe that leads into the float bowl chamber at the top.
That vent hose then leads down to the charcoal canister and is regulated On/Off by the vapor solenoid attached to the original canister. Toyota calls it the Outer Vent Control Valve.

When the engine is off, the solenoid is open, allowing gas fumes to waft down into the canister.
When the ignition key is turned On, the solenoid closes and the vent hose is blocked.

That vent hose needs to go somewhere now with your new canister since it doesn’t have an extra port.

It’s important to vent the float bowl after shutting down to prevent all those gas fumes from entering the air cleaner housing (and migrating to the distributor if it’s VCVis toast).

View attachment 3301655

Thanks, that makes complete sense. The problem is what do I connect that line too?
Tank and Purge are self explanatory, with the third connection (Air) do I use it to connect the carburetor line or the vent to the frame? And then what do I do with the other line?

 

[4runner2FJ60]

here is how I ran mine. There are many threads on Mud, but probably hard to sift thru them all.....
The top port goes to higher pipe at firewall, the bottom hose below that goes to the lower pipe firewall closest to passenger side with a brass T fitting inline, that feeds to the solenoid valve. The stand alone third port goes down under canister into frame/fresh air vent like factory one. hope this helps!

 

[CruiserTrash]

The carburetor float bowl is half way full of fuel at engine shut down. The hot engine cooks it and the fuel then vaporizes and travels.
On a stock 2F engine on the FJ60, there’s a large breather hose connected to a biggish pipe that leads into the float bowl chamber at the top.
That vent hose then leads down to the charcoal canister and is regulated On/Off by the vapor solenoid attached to the original canister. Toyota calls it the Outer Vent Control Valve.

When the engine is off, the solenoid is open, allowing gas fumes to waft down into the canister.
When the ignition key is turned On, the solenoid closes and the vent hose is blocked.

That vent hose needs to go somewhere now with your new canister since it doesn’t have an extra port.

It’s important to vent the float bowl after shutting down to prevent all those gas fumes from entering the air cleaner housing (and migrating to the distributor if it’s VCVis toast).

View attachment 3301655

@OSS To get this AC Delco to behave like the original, could you tee the vapor separator and outer vent lines together, then plumb them to the canister intake?

Why does Toyota use two separate intakes? Is there a reason to keep the bowl vent and tank vents separate that I’m missing?

Not being able to figure this out has kept me from installing one of these.

 

[87CRUSR]

Standing by as well...

 

[imratz]

@OSS To get this AC Delco to behave like the original, could you tee the vapor separator and outer vent lines together, then plumb them to the canister intake?

Why does Toyota use two separate intakes? Is there a reason to keep the bowl vent and tank vents separate that I’m missing?

Not being able to figure this out has kept me from installing one of these.

I’ve been thinking about a T fitting as well. The carburetor and intake lines into one port, then the purge to purge and the air into the frame.
I’m home next week and will let you know how it goes

 

[4runner2FJ60]

There are other posts on this replacement filter, its been done many times........

 

[CruiserTrash]

There are other posts on this replacement filter, its been done many times........

Yet none of them explain how to keep the original functionality of Toyota’s “extra port” canister.

 

[OSS]

Why does Toyota use two separate intakes

Its because the vent port that accepts the vapor line from the gas tank is restricted by the check valve inside the canister. Several psi are required to migrate past the check valve and the carburetor float bowl vent has zero pressure.
That’s why it has its own open unrestricted port on the original canister.

 

[CruiserTrash]

Its because the vent port that accepts the vapor line from the gas tank is restricted by the check valve inside the canister. Several psi are required to migrate past the check valve and the carburetor float bowl vent has zero pressure.
That’s why it has its own open unrestricted port on the original canister.

Makes sense, thanks for explanation. I’m sure an in-line check valve could be sourced, no? Put that on the line from the tank, before the tee.

 

[CruiserTrash]

@OSS Ga e it some more thought. Float bowl is unrestricted because it’s a small amount of vapors. Tank has a check valve because if that was unrestricted it’s a lot of vapors that could swamp the canister and eventually prematurely kill it.

Sound right?

 

[OSS]

Sound right?

As I’m guessing it—-
The charcoal canister is primarily an emissions reduction component. It’s supposed to trap gas vapors to be burned off when the engine is running.
The reason there’s a check valve in the canister tank line is to apply a constant 3psi (or whatever it is) vapor pressure in the tank to help prevent even more evaporation. The higher the vapor pressure in the gas tank, the less the liquid fuel vaporizes which is a good thing when the goal is to reduce emissions.

 

[imratz]

here is how I ran mine. There are many threads on Mud, but probably hard to sift thru them all.....
The top port goes to higher pipe at firewall, the bottom hose below that goes to the lower pipe firewall closest to passenger side with a brass T fitting inline, that feeds to the solenoid valve. The stand alone third port goes down under canister into frame/fresh air vent like factory one. hope this helps!






View attachment 3302614View attachment 3302615

Dude, this is spot on! Thanks for sharing the connection layout. If we ever cross paths, tequila is my treat!

 

[garfieldthecat]

Hoping I can get some clarification on the routing for the GM canister. The EVAP page from the emissions manual posted by @OSS shows the tank line as a stand-alone line entering the EVAP canister. It also shows the purge line and the line going to the Outer Vent Control Valve (OVCV) solenoid as being non-check-valved and flowing freely. However, I see that most folks that have done this replacement have teed the tank and OVCV hoses on the tank port for the GM canister rather than teeing the purge and OVCV hoses on the purge port, except for @imratz above. Here are some photos to help me explain. It seems the way to go on this replacement is to tee he purge and OVCV hoses on the purge port rather than tee the the tank and OVCV hoses on the tank port? I'm inclined to install this the way @imratz did, but curious to learn why the tee on the tank line may be correct.

 

[imratz]

I chose this way based off of another post. I can tell you it solved my problem and I haven’t had any issues since.
I’m sure there’s more than one way that works

 

[CruiserTrash]

@garfieldthecat The OVCV and tank lines are both from sources that are offgassing- sources that need to go INTO the canister. The purge line is the only one with OUTGOING flow.

I’m not sure if the the AC Delco et al canisters have check valves (I assume they do), but for safety I teed mine accordingly: both incoming sources (OVCV and tank) teed and running to the “tank” input on the AC Delco, and the ”purge” output feeding the purge to the carb.

If you tee the OCVC (flow from carb to canister) and purge (flow from canister to carb) any check valve present in the canister is not going to work for one of those (the OCVC). Luckily the way Toyota set it up, you have valves on the purge and OCVC lines, otherwise with the way you’re trying to tee the purge and OCVC lines you’d set up a loop from the float bowl to the tee and back to the float bowl. Without the valves you might set up some kind of siphon loop of fuel while driving - if one valve fails that might happen the way you’re thinking of plumbing it. I mean, maybe that wouldn’t happen … but the fact remains that teeing it that way means the canister isn’t going to operate the right way, the OCVC is going to take that offgassing fuel in the float bowl and route it to a dead end at the check valve of the canister because the valve only lets vapor out and not in. It essentially wouldn’t let the float bowl vent.

 

[garfieldthecat]

Thanks @CruiserTrash , so the OVCV allows the float bowl to vent into the canister on the same line as the fuel tank with the tee in the tank line. Makes sense. I think the GM canister does have valves on the tank and purge valves. Working with non-oem replacements makes it bit confusing and since I am in a smog and emissions testing state, I really need to get this right so I can register the truck once it's running. Appreciate everyones feedback on this.

 

[CruiserTrash]

Thanks @CruiserTrash , so the OVCV allows the float bowl to vent into the canister on the same line as the fuel tank with the tee in the tank line. Makes sense. I think the GM canister does have valves on the tank and purge valves. Working with non-oem replacements makes it bit confusing and since I am in a smog and emissions testing state, I really need to get this right so I can register the truck once it's running. Appreciate everyones feedback on this.

Smog area here too.

Original canister:
OCVC inlet
Tank inlet
Purge outlet
Fresh air

New canisters have:
Tank inlet
Purge outlet
Fresh air

Since you’re down one inlet on these new GM canisters versus the original Toyota one, you have to tee together the two inlets that Toyota designed into the system. I think it’s really as simple as that.

 

[OSS]

The outer vent control valve on a normal engine HAS to be closed when the ignition is on. If it’s open or the float bowl vent line has been vented directly to the charcoal canister or atmosphere — starting the engine is a lot more laborious.
I’ve tested it.
I’m not sure exactly why this is — but it definitely did it on my 2F.

So bottom line: the float bowl vent line can’t be open when the ignition is on.