So as we all know, there are 4 tubes coming from the sending unit; one for the vent, one for the vapor canister, one for the pump feed (1983 carbed) , and one for the return. Obviously, the large tube is for the pump feed. My question is: which one goes to the vapor can and which one to the return? I'm not sure, but I may have gotten them switched when I was replacing the short rubber hoses. I never disconnected the one with the vent, so I know that one is correct...

 

The return line goes to the bottom of the tank. So blowing into it using low pressure air should bubble through the fuel. Should be able to hear it at the filler neck with the cap off.

The line that goes to the CCP canister has a restriction in it at the tank. And goes to the top of the tank. The restriction will back pressure any compressed air.

With these checks should be able to figure out which line is which.

RBob.

 

Thanks. I don't "think" I mixed them up, but not 100% certain...

 

got a nice hand drawing over here, with some other links. https://www.thirdgen.org/forums/tech...ding-unit.html

 

Does that diagram apply to the '82-'83 carbed cars? Or just the '87-'92 fuel injected?...

 

you got me on that one, didn't even think about older units. I don't even know if the carbed cars have fuel pumps on the engine or the tank! maybe someone else will chime in......

 

Hey T.L. Just got to thinking on this, check the part number or go to rock auto and see if the sender is same for the years in question. that may give you a clue.

 

 

Thanks gt4373. That helps a lot...