My truck has a new fuel sender fitted, where does the pipe that comes off the top go. it looks like it should have a pipe attached. Is it a vent pipe? Thanks
Assuming in-cab tank, the line off the top is the fuel supply heading towards the carburator. It goes down through a fitting in the cab floor, through a flex hose and connects to the fuel line which on my 57 GMC forward on the inside of the right frame rail to the engine compartmment.
Ah, i see. It is in cab tank but the feed must be taken from a point at the bottom of the tank as the pipe off the sender isnt connected to anything. Would it be ok to cap this pipe off in that case. Truck is 57 GMC short bed, GM front clip, 350/350.
Me too! I had exactly the same thing with my fuel tank. When I got the truck the fuel gauge didn't work (reading full all the time), everything looked OK from the outside so I bought a new gas tank sender unit from CP. When it came I thought what the ...'s this pipe for. And when I took what I though was the old sender off the tank I found there was nothing at all on the inside - it was just a plate someone had put in place over the hole and wired the gauge line up to for good measure. Anyway the tank came out and I found some one had punched a hole in the bottom of it and fitted a new supply line from there. Which I guess is what you have. For what it's worth I think it's better to plug the one in the bottom and put the correct one in from the top. That way if you ever get a break in the fitting or in the line you don't get gas pouring out. And, you can disconnect the lines to work on the fuel system without having to drain the tank. It's what I did.
The Pipe at the top is the Suction Pipe. It needs to run to the Fuel Pump DO NOT Attach a line to the Drain Fitting at the Bottom of the Tank! The Screen on the Sender sits 1/2" From the bottom so that Water will collect below it. The drain has no screen.