Help the idiot - Vapor Lines

[lintcollector]

So I do accounting by day and am learning truck by night. I can't figure out the purpose & where the vapor lines are supposed to be attached. Or do I need them if my tank is EEC?

I bought the truck already torn down, but I don't think having extra means I'm more efficient.

In reference to the below pdf, Where are the different ends supposed to connect, or do they function like a plumbing P-trap to catch/prevent vapors?

It's a 1972 Chevy C10 402ci, if that helps.

A - Goes to Fuel Pump
B & C - Are buddies/connected by hose
D - no idea...

Should #5 be vertical or horizontal?

[jradford]

Go to the LMC website and look at their catalog pictures of fuel lines. It will explain what you want to know. Easier than me scanning a picture for you. I have a 72 C20 and the the hooked line is a vent that runs along the frame rail on the passenger side. I overfilled my tank and had fuel running out of it until it drained down. If you can't figure it out from that let me know and I will see what other info I have.

[GASoline71]

A does not go to the fuel pump. It goes to a charcoal canister in the engine compartment. The big loop (5) goes up into the passenger side pillar between the door and the rear glass. D connects to the fuel tank.

Here is how the loop attaches to the tank and where it goes in the pillar. Then it runs into another hardline along the tank edge then through the floor. This is in my 1972 GMC C15.

http://67-72chevytrucks.com/vboard/s...&postcount=313

Gary

[lintcollector]

Originally Posted by GASoline71

A does not go to the fuel pump. It goes to a charcoal canister in the engine compartment. The big loop (5) goes up into the passenger side pillar between the door and the rear glass. D connects to the fuel tank.

Here is how the loop attaches to the tank and where it goes in the pillar. Then it runs into another hardline along the tank edge then through the floor. This is in my 1972 GMC C15.

http://67-72chevytrucks.com/vboard/s...&postcount=313

Gary

Great, thanks for the info Gary. I pulled the image from LMC and only added the letters as a point of reference. Thanks for the link to see how the mysterious 5 loop fits into the puzzle. I'll see if I can find any parts or rails attached underneath.

Thanks for your help, and your rebuild project looks great.

Mike

[GASoline71]

No problem Mike. And thanks!

Gary

[Ironhorse]

lintcollector, I have the EEC corner vent line (shown as #5 part) listed in the parts section if interested. Not sure, but may have the section that goes beneath the cab also, have to do some searching in the parts shed. I moved the tank on my '71 4x4 to under the bed behind the axle.

[lintcollector]

Originally Posted by Ironhorse

lintcollector, I have the EEC corner vent line (shown as #5 part) listed in the parts section if interested. Not sure, but may have the section that goes beneath the cab also, have to do some searching in the parts shed. I moved the tank on my '71 4x4 to under the bed behind the axle.

Thanks Ironhorse, I appreciate that. I went and took a closer look and I can't find anywhere to hook up any vapor hoses onto the tank. I took the tank from a 1970 C20, so I'll have to check how/if they are vented or not.

[Steeveedee]

1970 C20 trucks didn't have the vapor recovery system.

[lintcollector]

Originally Posted by Steeveedee

1970 C20 trucks didn't have the vapor recovery system.

I will go ahead and proceed without them, until I stall out, or get high from fumes. I'll let you guess which option I'm hoping to experience.

Thanks Steeveedee

[Steeveedee]

Originally Posted by lintcollector

I will go ahead and proceed without them, until I stall out, or get high from fumes. I'll let you guess which option I'm hoping to experience.

Thanks Steeveedee

:LOL: Just get a vented cap for a '70 truck and you're good to go. If you have the EEC stuff under the hood, just put caps on all the metal fittings, and the plastic fittings on the vapor canister. Leave the vapor canister there if you think you might need it again, one day. Just know that there are replacement vapor recovery canisters, and that there is a filter in the bottom that needs to be serviced periodically.