Misc Fuel line leak

[Petescj]

I have a pretty good fuel line leak on the driver side of my 82 CJ7. I didnt originally follow it and my counterpart told me it went from tank to fuel pump so I ordered that. Well now that my knee is feeling better I went to install it.

Unfortunately it looks to me that this line just goes from the tank to the charcoal canister. Thats fine Ill just order the correct on as I was going to replace them all anyway.

My real question is should that line really be leaking a decent amount of fuel? I thought that was mainly valors through the canister not raw fuel?

 

[Manic Mechanic]

Are you looking at the right line? My fuel line runs on the passenger side of the frame and my return line is on the driver's side

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[Petescj]

Are you looking at the right line? My fuel line runs on the passenger side of the frame and my return line is on the driver's side

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Exactly. My return line is rusted out. Why so much raw fuel?

This Jeep has a different tank than any other Ive ever seen. It sits behind the rear axle and hangs low. Not like the ones Im used to that are more centered under the rear floor area.

Ill try to get some good pics tomorrow.

 

[Belizean]

I bought years ago a 22 gallon tank that hung low like you are talking about. Good for long trips, but I got hung up a couple of times because of that. Went back to 15 gallon. But all my lines ran in the factory locations.

 

[Manic Mechanic]

I thought all 7s hung behind the rear axle.
As for the raw fuel your return line would have raw fuel flowing through it while the engine is running

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[TSB8C]

Like Manic said, fuel supply line is on passenger side, return line is on driver side. You also have the line from the tank vents to the canister also on the driver side. The fuel supply and return both have liquid fuel flowing under pressure (well, vacuum on the supply side from the pump sucking it from the tank). The return comes from the fuel filter and has pressurized fuel not used by the carb going back to the tank. Either of these gets a leak, you have liquid gas coming out.

The tank vent to the canister should not have liquid fuel, but only vapors that pass from the tank, through the liquid and rollover check valves (behind rear driver side fender well), and up to the canister. If you have liquid fuel in this line, (a) your tank is overfilled because the vent connections are at the top, (b) your check valves aren't working, and (c) your charcoal canister has probably been ruined from saturation of the charcoal.

If your gas cap is preventing the escape of vapors (as it should be), and the evap system is not functioning (not purging vapors like it should be), then on a hot day when the vapors in the tank expand and if the tank is full, you can get fuel trying to escape through the evap line and any slight crack in that line will certainly leak.

 

[Manic Mechanic]

In my case both supply and return are pressurized due to EFI. my supply is 60 psi return is something like 15 I think.

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[Petescj]

I bought years ago a 22 gallon tank that hung low like you are talking about. Good for long trips, but I got hung up a couple of times because of that. Went back to 15 gallon. But all my lines ran in the factory locations.

Im familiar with the plastic 22 gallon tanks. This isnt one. Honestly it looks almost like an auxiliary tank to me.

 

[Petescj]

I thought all 7s hung behind the rear axle.
As for the raw fuel your return line would have raw fuel flowing through it while the engine is running

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No the 76-86 Cjs use this style tank. When I post pics of mine youll see the difference.

 

[Petescj]

Like Manic said, fuel supply line is on passenger side, return line is on driver side. You also have the line from the tank vents to the canister also on the driver side. The fuel supply and return both have liquid fuel flowing under pressure (well, vacuum on the supply side from the pump sucking it from the tank). The return comes from the fuel filter and has pressurized fuel not used by the carb going back to the tank. Either of these gets a leak, you have liquid gas coming out.

The tank vent to the canister should not have liquid fuel, but only vapors that pass from the tank, through the liquid and rollover check valves (behind rear driver side fender well), and up to the canister. If you have liquid fuel in this line, (a) your tank is overfilled because the vent connections are at the top, (b) your check valves aren't working, and (c) your charcoal canister has probably been ruined from saturation of the charcoal.

If your gas cap is preventing the escape of vapors (as it should be), and the evap system is not functioning (not purging vapors like it should be), then on a hot day when the vapors in the tank expand and if the tank is full, you can get fuel trying to escape through the evap line and any slight crack in that line will certainly leak.

Im going to go through and track the line again. Im betting its the return line and not the canister line. It never left a drop by the canister area and it wouldve if this amount of fuel went through.

Now I know why I see these lines being replced while the tub is removed. It sure would make it easier.

 

[Belizean]

Im familiar with the plastic 22 gallon tanks. This isnt one. Honestly it looks almost like an auxiliary tank to me.

Mine was all steel tank. A rectangular shape with no rounded corners. Looked like a big brick that hung about another 5 inches lower than a 15 gallon tank

 

[Petescj]

Mine was all steel tank. A rectangular shape with no rounded corners. Looked like a big brick that hung about another 5 inches lower than a 15 gallon tank

Hmm never heard of that one but sounds a bit like mine. It hangs low and I hate it. Hard to get a good pic of it but hear it is with the one spot of my frame that needs a better repair than the previous one.

 

[Petescj]

It is all behind the rear axle nothing above.



Its got horrible ground clearance. Its on the list of things to be replaced.

 

[CJ]

It is all behind the rear axle nothing above.

View attachment 100930

Its got horrible ground clearance. Its on the list of things to be replaced.

View attachment 100931

This pic looks like a car / truck tank? I don't see straps, so how is it bolted on? Could it be out of a truck? Truck tanks are usually frame mounted. How is the filler hose attached?



Typical GM straps:

 

[Petescj]

This pic looks like a car / truck tank? I don't see straps, so how is it bolted on? Could it be out of a truck? Truck tanks are usually frame mounted. How is the filler hose attached?

View attachment 100932

Typical GM straps:
View attachment 100934

The whole thing is inside a skid plate that has sides on it but no top. I dont see any straps. Theres alot of rubber inside to isolate it. At first I thought it was metal but it does seem to be made of a plastic composite. I believe Belzian may be right about it being the 22 gallon version. I thought that had a different shape though and went up over the axle as well. This skid plate bolts directly to the rear crossmember and another in front of the tank. Ill be bringing Vader out of hibernation next week so Ill have something to compare it to.

 

[Manic Mechanic]

Looks like a 20 gallon CJ tank

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One I'm working on ATM

 

[Petescj]

Looks like a 20 gallon CJ tank

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One I'm working on ATM

Ugh. Sure does look like that pic. This is going to make me rethink this whole fuel system.

 

[Manic Mechanic]

Not really that much difference between it the 15. Other than some mounting and parts

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[mdeluca]

These are some photos of my 1986 CJ7 (inline 6) frame and OEM plastic fuel tank. This was during the restoration when we took the body off to paint. This, I believe, is an all stock configuration.

Hope it helps,
Mike

 

[Manic Mechanic]

That's the 20

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