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2 return fuel lines?
Posted: Mon Jun 05, 2006 10:18 pm
by antt
will be hooking up the fuel system in the next few days, but noticed there are two return lines from the motor going back to the tank. one of them goes straight into the tank, whereas the other one went into a little plastic box mounted onto the tank, then back into it.
my surge tank only has one return line spot, so can i just 'tee' these two return lines together and run a single line to the surge tank? or will it cause drama's
btw, motor is g16b...1.6 16valve injected
Posted: Mon Jun 05, 2006 11:35 pm
by Gutless
The line that runs to the plastic container is just a breather, It will not carry much more than vapour.....EVER!!
If you have nowhere to run it with your new setup, tap it into your filler neck ( if you still have one) or if your tank/ cell has internal venting, just 'T' peice it into your return line.
Posted: Mon Jun 05, 2006 11:37 pm
by christover1
sounds to me like it may be part of the tank breathing system, rather than a return line.
evaporated fuel collects in the plastic box, for return to tank, but it lets fumes run up to the carbon cannister.
I could be horribly wrong, tho, and don't know enough about efi to give an answer..
christover
Posted: Tue Jun 06, 2006 4:33 pm
by antt
so if it is a vapour line, will it cause any problems to return it to the surge tank, tee'd into the normal return line?
btw, i dont have a filler neck to run it back into
Posted: Tue Jun 06, 2006 4:39 pm
by "CANADA"
antt wrote:so if it is a vapour line, will it cause any problems to return it to the surge tank, tee'd into the normal return line?
btw, i dont have a filler neck to run it back into
Wont it vapour lock that way?
Posted: Tue Jun 06, 2006 4:46 pm
by christover1
So long as the tank has some way of letting air in, as the petrol is sucked out. If not, tank could build up a huge vacuum, and car will stop, or tank can get damaged.
Also needs an expansion ability, or fuel pressure build up, ie when parked in the heat, will escape somewhere, usually with unpleasant results.
My carbon cannister died, a common problem for me.
I now breath the tank with a fuel line up to a fuel filter, pointing down so rain don't get in. This is not the best idea, but works till I get another cannister.
My breather runs from 1 side to the other, before going up, then down. This way fuel don't spill out, when I am flopped (all too common

)
Some people use a fuel cap that breathes, this was a common thing on some older vehicles.
christover
Posted: Tue Jun 06, 2006 5:11 pm
by antt
MADZUKI wrote:antt wrote:so if it is a vapour line, will it cause any problems to return it to the surge tank, tee'd into the normal return line?
btw, i dont have a filler neck to run it back into
Wont it vapour lock that way?
fawks me, this is the first fuel setup i've done, so have nfi

Posted: Tue Jun 06, 2006 5:12 pm
by antt
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Posted: Wed Jun 07, 2006 11:18 am
by just cruizin'
How does your tank breath?
I would recommend the cannister idea as this goes to atmosphere. It should be vented outside the vehicle at least.