Fuel squirting out of the gas cap holes

[RedGTRUSA]

Hey Guys, I can’t figure out a way to stop the fuel from squirting out of the gas cap holes (pressure holes). My mechanic and friends can’t see any reason for this. I have a bridge line going from tank to tank, I’m stumped.

[stig]

When you're filling up, or when you're driving?

[mhussa]

Or do you park at strange angles? see the reply by GreenV8S in this thread:

www.pistonheads.com/gassing/topic.asp?t=219313&f=20&h=0

[GreenV8S]

I assume you have ruled out sillies like being parked on a steep slope!

Do you run a recirculating fuel system with a return to just on tank? Is it that tank which is overflowing? If so, this might be a sign that the amount of fuel being returned is more than the balance pipe can handle with the available pressure differential. Otherwise the only reason I can think of is thermal expansion if both tanks have been filled with cold fuel which has then been warmed inside the tank.

[mhussa]

yes I see the flaw in my question but the concept described in the thread is what I was letting him know about.

[gtrclive]

Do you mean the Vent Holes or the cap it's self ? If its the cap just tighten up the 10mm nut on the bottom of the cap as this puts more tension on the cap when closed..

Does this happen only when full ? Do you have the twin pump setup. If so have you fitted the None Return valves after the fuel pumps ??

>> Edited by gtrclive on Saturday 19th November 17:10

[RedGTRUSA]

I have a twin pump setup and the fuel squirts out of the vents while driving or parked. It seems to be random.

Thanks for all the help!

[andygtt]

If you are using a twin pump system that only uses one pump at a time, one possibility is that one of the pumps non return valves has failed and that the running pump is forcing fuel past the non running one and filling the other tank up with fuel as well as supplying the carb.

[RedGTRUSA]

Yes I only use one pump at a time. This could be the problem. Would I benifit IF I had both pumps run at the same time? I was thinking of running both pumps to help stop fuel starvation at the track.