Suburban Tank Fuel Sending Unit

[Bamm]

Hey guys, I'm installing my suburban (I think) tank this weekend and there are 4 hoses coming out of the sending unit. Can anybody tell me left to right what they are and where they go from here? Thanks guys.........Jerry

[JimKshortstep4x4]

This is just a guess as the tank on my son's 72 Burb has the fittings made into it and the sending unit only has one tube on it, (the fuel line).

Left to right, fuel fill vent, charcoal canister, fuel line, fuel return.

Jim

[Bamm]

Thanks for the info Jim. Sounds like maybe the tank I have is off of a newer model? Will a '72 sending unit fit the same? Anybody know? Any help would be great. Thanks, ....Jerry

[neonlarry]

Thats not a newer sending unit, at least it looks the same as mine (I just had the tank out) 2 & 4 are vent lines.

[Bamm]

Where do they vent to? Sorry, I don't have a clue on this one. I have only had in cab tanks. If (left to right) hose #1 is fuel going out, and #2 and #4 are vent lines, what is #3? Return? If so, return from where? Thanks guys for helping me out.........Jerry

[neonlarry]

I'm not sure if 1 or 3 is line to fuel pump (popping the cover off will tell you for sure) the other is like Jim said 'fuel fill vent' (there should be another smaller connection on you fuel fill pipe). By the way good luck finding the proper size fuel fill connector hose, and then its about a $1 an inch.

[Bamm]

I took the unit out and here's what I know: #2 has some kind of little small filter doo-dad that only drops down into the tank about 1 1/2 inches. Filter? Vent? Line #3 is definitely the fuel pickup line. #4 looks to be a skinny vent line? #1 is the largest diameter line but I don't know what it's for. I'll try to snap a pic of it tomorrow to see if that helps jog anybodies memory. Thanks Larry and everybody else for helping me with this. Later, .........Jerry

[neonlarry]

Jim and I both have said #1 is a vent line that goes to the fuel filler inlet (where you pump the gas in) if you look up inside the fender where it comes thru you will see a nipple where the hose goes.

[JimKshortstep4x4]

#2 can be used as a vent if your truck is not set up with the charcoal canister. #4 would be used on trucks that have AC so that part of thefuel being pumped to the engine is returned to the tank, (the fuel pump would have two outlet connections on it it with the small line going back to the tank).

Depending on how your truck is set up, you may not need #4 but you will need 1,2, and 3.

Jim