Fuel tank breather

harvo · Post by **harvo** » 02 Jan 2007, 17:31

I've got my twin cam in and running but have a small steel line running from my tank to eng bay can't remember were it went/should go on new motor? With engine running the fuel tank pressurisers and forces fuel our the above mentioned line. Should it go to a charcoal canister? my rodeo neva had one think it may have gone to the emission stuff on intake/carby? could it be plumbed into the intake if tank isn't pressurising would that fix it or would i need the hole EGR vale set up. I think that's what there called. Do your Gemini's have a similar set up
Appreciate any help. Thanks Harvo

Storm · Post by **Storm** » 03 Jan 2007, 20:40

If it is pouring liquid out the pipe you have a problem, maybe the fuel cap is not venting properly or something. All EFI cars pressurise the tank to a certain degree as the return line itself is pressurised. Gottta love that whistling sound on a hot summers day. But to be pouring liquid out one of my guesses is that your fuel lines are restrictive and while the pressure going into the tank from the return line is "normal" for an injected car the fuel pump itself is either not recieving enough (doubtful as the car runs and I am assuming very well) or the line after the fuel pump is restrictive lowering the pressure difference while not affecting performance.

Also the carbon cannister is for vapour only. It will not retain liquid petrol.

Post by **IZU069** » 05 Jan 2007, 20:09

Are you using the return line? IE - EFIs have a reticulation system - pumped from tank to the injector feed and back to the tank.
Carby systems (usually) only have the feed from the tank.
(There can be other tank pipes, but these breathers for vapours etc to the charcoal canister etc.)
Maybe you got your vents & feeds mixed up (especially of your EFI fuel tank has 3 lines - feed, return & vent)?

Storm · Post by **Storm** » 05 Jan 2007, 21:55

Gemis have a return line and I am pretty damm sure that Rodeos and Jackaroos do to. Check the tank and see what you have coming out of it and see where they go. Return lines more often than not are on or very near the sender/pickup unit while breathers are usually near the top of the tank or exiting the expansion chamber.

harvo · Post by **harvo** » 25 Jan 2007, 17:51

Thank's for all your help, but i still have the same problem. I've checked out my system but dont know whitch line is whitch? There are 3 lines comeing from the tank the large one is fuel to engine? The medium is fuel return? and the small one is a vent? this is how it is hooked up at the moment, But if i leave the fuel cap on it presurises and forces fuel out the same line wether the car has been started or not. Also when it is running there is a lot of fuel one of the lines that runs to the top of the filler neck and some leakes past the cap. I have'nt really dealt with this kind of thing befor so I'm not to sure were to start?
Again thanks for all your help. I owe you guy's a beer

cheers Harvo