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Guys, need some help. Was driving truck, 1988, F-250, 460, and smelled gasoline. Pulled over and found gas leaking from canistor right below battery on passenger side. Looks to be emmissions stuff, but was leaking gas. Tried to trace lines. One goes to a lower canistor. Another goes to PCV valve. Last seems to go to top of fuel tank.
Can someone explain this system to me. Leaking upper canistor has seen some battery acid on it, and may have some holes.
'88 should be fuel injected so it isn't an overflowing float bowl.
Had you just filled up?
Is it very hot where you are?
Perhaps you have the dreaded 'cross flow' condition with your tank selector valve.
At any rate, my best guess is that one of your tanks is overfull and raw fuel instead of vapors is making it to the canister through the vent tube.
'88 should be fuel injected so it isn't an overflowing float bowl.
Had you just filled up?
Is it very hot where you are?
Perhaps you have the dreaded 'cross flow' condition with your tank selector valve.
At any rate, my best guess is that one of your tanks is overfull and raw fuel instead of vapors is making it to the canister through the vent tube.
I have that cross flow problem where my rear tank pumps fuel into my front tank. I haven't had leaking fuel from that canister but on hot days I have had a lot of fuel odors coming from under the hood. Is the cross flow caused by a bad switch or a check valve on the front tank pump? Sometimes I can't start the truck using the front tank, but after it is running can switch to it.
Thanks for the replies. I found some info. It is called a carbon canistor. Fuel vapor only is supposed to be vented there from the tanks and trapping the hydrocarbons in charcoal.
The truck is fuel injected.
Both fuel tanks are very full.
Drove truck with increase in elevation @ 2000 ft.
Temps only @ 80, but swing is from 45 to 80 degrees.
Not sure about the cross flow issue.
I think when cool, it won't leak, and if I can burn some fuel out of the tanks, I should be OK. I would like to replace the upper canister. Does anyone have any method of finding a part #?
88 has a pump each tank, then a main pump in the rail. cross flow between tanks was mostly from 90 and newer, where the pump was only in the tank. what happened, was that the check valve would go bad in the pump, and it would push the return line fuel into the opisite tank it came from.on my 89 [3 pump system] I started to smell fuel with a full tank, it wound up being a hole in the tank.as far as fuel in the charcoal can, there is a check valve on the tank [all systems, all ford products] that closes when the liquid pushes on it. these go bad, and are easy to replace, but you have to drop the tank , or remove the bed, to do so. if this valve goes bad, the vacume to draw off the vapor, sucks fuel instead, on a full tank.once the fuel level drops, it should stop doing that
Thanks guys. Dusty and Jim, you guys are correct on the tank check valve/rollover valve. Cool front moving through today, and no liquid fuel from canister. Now that you mention it, yesterday when fuel dripping, I opened the cap of each tank. Rear tank was just a pssst, but the front tank also had a pop or thud noise.