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Hi all, new to the site and I just purchased a 1994 F150. Quick question for you. I was recently driving my 94 F150 with a 5.8 in it and noticed the smell of gas. Upon further inspection it seems like gas was pouring out of one of the Caps of the charcoal Vapor canister. And doing some research it seems like I have two options. It's a two-tank truck so I can drop the tank and replace the fuel pump or I can possibly just remove the system. For a quick fix I just plugged the hose running into the cannister. This truck is from California and I am in New Jersey now and the truck no longer needs inspection do to its age. It seems like it runs fine and I don't have an engine light on but is there any downside to keeping it this way? I have attached pics here.
You have a vapour (vent) line attached to both tanks. Theoretically, if vapours build up (like when the tank starts to get hot in the middle of the day and the fuel starts expanding) the vapours will be pushed out through that line and when the purge valve is open, the vapours will be burned off.
When the purge valve is closed the vapours can be temporarily filtered through the charcoal in the canister. That's how that works.
There is never a situation where raw gas is supposed to be coming up that line. That is extremely dangerous to have happening.
My best guess is that you may have a faulty check valve in one of the tanks (the one that's not running) and you are getting "cross filling" which is overfilling your tank and pumping it out the vent line.
Bottom line is no, it is not even close to safe to leave it like that. Catastrophic fire waiting to happen.
I am not sure. Both tanks are full with gas. I'm wondering if I over filled the tanks? That would be a lot easier of a scenario then pulling the tank. What's your best guess on what module is filled. I'm thinking it's the front. The rear tank was what was being used when the fuel started going into the canister. My plan for now is to keep the switch on the front and see if it continues to stay full and see if the rear is draining. I'll keep you updated.
It's a bit of a detective story - you have to keep track of what's going on for a bit to narrow it down. If you've been running on the rear tank odds are good that there's a check valve gone in the front tank so the rear pump is overfilling the front.
So as you've planned, run your front tank down to about halfway then switch to the rear and watch every once in a while to see if the front tank level rises again. If you end up with a full front tank again, that would tell you that the front tank has a bad check valve and is being cross-filled.
Then do the same thing with the back tank just to be sure.
That should narrow things down and tell you if that actually is the problem.
Other than the obvious concern about pumping raw fuel into the vapour canister, the other thing about having a bad check valve is that you generally don't get proper pressure to the fuel rail because some of it is bleeding off at the bad check valve.
If you follow all that.
07-11-2016, 09:30 PM
5.8 Charcoal Vapor Canister
