I feel dumb for asking this, but I just wanted to make sure I was doing my fuel injection service properly. what(and why) are the 3 fuel lines on the sender? is it supply, return, and another for a second pickup? and which is which? thanks

 

There isn't any normal fuel injection service so what are you doing?

 

Im sorry, i have access to a motorvac fuel injection machine that taps into the fuel lines to flush the fuel rail and injectors better than the stuff you can just add in through a vac line.
my main question is, what are the three lines that connect to the fuel sender under the passenger seat?

 

Got a pic of it?

One is certainly fuel feed.
The other is probably return
Is the 3rd one a vent so when you pump gas, the air has somewhere to escape to?

 

Yea i'd love to see how that works

 

there are normally 2 return lines

 

There's only one return line. The line on the passenger side is carbon canister purge. The other two are pressure and return line.