Fuel vapor canister

[cohiba]

While checking out my fuel starvaton problem I noticed that there is a metal fuel line coming from my tank to the right side of the engine bay. The other two lines are the main fuel feed and the other the return. But I remember years ago there was a coffee can shaped canister there on the right side of the inner fender. After a couple engine changes and two years of my son driving the car someone forgot to put that back where it belongs. Could this be the problem to my fuel starvation problems? (notice I haven't mentioned vapor lock once) Anyway I am going to order one from Bruces tomorrow and hook it up along with the new carb, mechanical fuel pump, and fuel tank sending unit. I know I have been running my car for years without it, but that doesn't mean it wasn't causing problems later down the road. Any thoughts?

[cohiba]

Well........I just might have stumbled upon something interesting. The metal fuel line that should be connected to the fuel vapor canister runs from underneath the car across the back of the firewall and then makes a right angle turn and runs parallel to the engine pointing to the front. Since I replaced the stock manifold with headers the fuel line is 1" from my headers and it is not closed off. Now the heat that is generated around my headers and in the engine bay must be being pushed back through that fuel line and right into the tank. Remember the fuel line is facing the front of the engine so while I drive the air is forcing all that heat right through that line. Wouldn't ya think? Read below what I found tonight and give me some feedback.

Fuel lines are placed as far away from exhaust pipes, mufflers, and manifolds as possible, so that excessive heat will not cause vapor lock. They are attached to the frame, the engine, and other units in such a way that the effect of vibration is minimal, and so that they are free of contact with sharp edges which might cause wear. In areas where there is a lot of movement, as between the car’s frame and rubber-mounted engine, short lengths of gasoline resistant flexible tubing are used.

[racydave]

the fuel supply line to the carb is the one to consider in any fuel starvation scenerio. it has probably a hose at fuel pump, at carb, hose in front of left rear tire, and hose at tank. also consider the fuel pickup in tank. since this is the suction side line integrity is important. mine was rusty, I replaced it all.

[cohiba]

Have new fuel sending unit on the way. Had to use the car the other day and she died on me. Dosconnected hose in front of electric fuel pump and cranked ignition to get a little gas to put down carb and pump would not even pump any gas. Got it out the old fashioned way. Man, that tasted bad. Anyway, let car sit for 10 minutes, poured a little gas down the carb and varooooom....she started right up and I continued my journey back home as if nothing ever happened. No more driving for me unitl all my fresh new parts for the fuel system come in and get replaced. WIll write about the happy ending in a week or so.

[cohiba]

I will be installing a new fuel vapor canister, the one by the battery in the engine compartment on my 72 Spider. There hasn't been one on there for years. I see the metal line that goes to it and I assume the out line will go to one of the brass nipples on the carb. Not sure of the exact set up. Does anyone know the correct hook up for these. The "in" line runs from another canister that is located in the trunk right below the fuel filler neck. It has a clear tube which runs into a plastic thing? (hacen't seen a picture of one to know the correct name is) which is mounted behind the fuel tank. From there the line goes to the engine compartment. (I am speaking about the in line that goes to the fuel vapor canister). Would anyone know what that canister under the fuel filler neck is? I will order one from Bruces which I am sure he knows what I am talking about, but would like some insight on how it all is connected up.

[ventura ace]

That thing under the fuel filler neck is the vapor/liquid separator. Vapors are gathered there and routed up to your charcoal vapor canister. Then, there should be a vacuum line from the intake manifold that sucks the vapors from the charcoal canister, but it should have a very small orifice in the line, since you don't want to be pulling a vaccum on the fuel tank. My '70 had a tiny orifice in the post that came off the intake manifold.

Alvon

[tglancy]

Do you have a diagram for the vapor recovery system. My Fiat 124 1975 is missing most of the emissions stuff (which is not required) but the smell of gas is likely come from the fact that charcoal canister is missing.

[rpconlon]

Terry:

The gas odor is often from a deteriorating filler neck. It is rubber and should be strongest from the rear of the car.
Also look down the carb venturis for leaking gas that shows it is time to rebuild the carb.
Replacing the cannister can help if the lines are still open.

Ron

[janet70]

My 1970 124 Spider, 1438cc engine has, from the charcoal canister, a short pipe that just sort of optimistically aims any emitted vapors in the general direction of the exhaust manifold to be burned off by the heat there. I was told by more than one Fiat expert that this is original to my car.

I still find it suspicious and peculiar. Heh!

[Dwight V.]

Janet, you have it right. That is what passed for vapor emissions control in 1970.

[ventura ace]

Janet, you have it right. That is what passed for vapor emissions control in 1970.

Well, almost right, anyway.

The big hose is not for vapors to exit. It is the "hot air purge inlet" to gather hot air from the vicinity of the exhaust manifold, and route it to the canister for the purposes of reactivating the charcoal. The fuel vapors, that come from the fuel tank into the 'fuel vapor inlet" at the bottom of the charcoal canister, are sucked out the top of the charcoal cannister through a hose that goes to the intake manifold,

Alvon

[janet70]

That seems to make sense.