Help me fix a fuel vent problem

[ScaldedDog]

88 4Runner. Doesn't look stock, but the fuel system largely is: Stock tank in stockish location (may raised 1"), stock charcoal cannister in stock location. The original vent hard line to the cannister used to clog up and create tons of pressure in the tank. I finally just replaced that hard line with fuel injection hose, and the pressure problem is solved.

Now, though, on long downhills sections (Think coming home on Chinamans or Poison Spider) I'll get a strong smell of gasoline, and gas will be running through the cannister and down it's vent hose. I suppose that isn't a surprise, since there is a direct and unobstructed path to the cannister, but I don't understand why this doesn't happen on stock (but not clogged ) hard lines, nor am I sure how to fix it. Is there a check valve in the stock vent line that prevents fluid flow? Any ideas what I could put in the vent line to accomplish the same thing? The cannister tested good a couple of months ago, but I assume it's ruined with all the gas that has run through it. I don't want to just buy a new one and ruin it, too. Ideas?

Thanks!!

Mark

 

[066wally]

Is the canister too low now that the tank has been moved higher. Just a thought, I'm not familiar withe the setup.

 

[ScaldedDog]

Thanks for the reply, but I don't think that's it.
Since a couple of years ago, the tank is actually lower than it has been in ages. The PO raised it 2" back in the 90s, and I lowered it an inch when I cut the body lift in half.

I am starting to wonder if the TV on the back of the motor (3VZ-E) is bad, and applying vacuum all the time.

Mark

 

[ScaldedDog]

Four years on, I'm still goofing around with this...

Have any of you guys ever taken apart a Toyota charcoal canister? I've come to the conclusion that mine is blocked, at least intermittently.

I thought it was a sealed unit, but what looked like a steel top is just a rubber cover that peels off. You can see it on the table in the photo below.


Looking more closely, it appears the top part with the ports may be threaded or pressed in:



I'm thinking if I could get that part off, I could replace the charcoal, clear any blockage, and clean the check valve. Before I have at this thing, can any of you shed any light on how it comes apart?

Mark

 

[Corbet]

All those tabs imply to me it’s threaded in there. Try giving it a twist. Is the part still available? Our 80-series canisters are long gone. The 80 guys cut them apart to rebuild. I’ve been avoiding this task for a long time. I get the pressure in the tank.

 

[ScaldedDog]

That's what I was thinking, too.

No, these are long discontinued. You can find old ones on eBay, but I have an old one... I bought an AC Delco one that I might be able to make fit, but it'll be a kludge, so I'd rather fix the OEM one.

Mark

 

[Corbet]

That's what I was thinking, too.

No, these are long discontinued. You can find old ones on eBay, but I have an old one... I bought an AC Delco one that I might be able to make fit, but it'll be a kludge, so I'd rather fix the OEM one.

Mark

Same same here. I've got some extras to play with, haven't made the time. If I run ethanol free I don't have issues. It only happens in summer temps. So I keep tabling the project for another day.

 

[ScaldedDog]

I was not able to get that canister apart. I still think that top piece unscrews, but didn't want to tear it up without a viable backup. I ended up blowing a ton of air through the thing, and replacing the tiny line between the tank and canister with one of more appropriate size.

Mark