Fuel pouring out of charcoal canister.

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McDougle

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Hello All,
I have an 86. I have just replaced my original 350 with a remanufactured vortec 350 with no provision for a mechanical fuel pump. My remedy for this was to get an intank fuel pump (and fuel tank) from an 87, and run a wiring harness with relay. I only have the fuel vapor line running to the charcoal canister as I desmogged while doing the engine swap.
Can anyone think of a reason, other than the tank was overfilled, why there can be fuel overflowing out of the charcoal canister? I know for a fact I only had 5 gallons of fuel in the brand new tank.
Thanks for your input!
 

squaredeal91

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Do you have dual tanks? Maybe selector valve malfunction sending gas through return to wrong tank? Or improperly routed fuel hoses. Maybe return is going to canister?
 

McDougle

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Do you have dual tanks? Maybe selector valve malfunction sending gas through return to wrong tank? Or improperly routed fuel hoses. Maybe return is going to canister?
Single drivers side tank and original fuel lines which are 3 different sizes to prevent mixup.
3/8" supply
1/4" return
5/16" vapor to canister
 

mtbadbob

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The carb has to be sending the fuel through the hose, maybe float level is too high??
 

TotalyHucked

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Or too much fuel pressure blowing past the floats? (I'm a fuel injection guy so I'm shooting in the dark lol). Carbs need what, like 5-8psi? And most in tank pumps run 58psi
 

squaredeal91

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Or too much fuel pressure blowing past the floats? (I'm a fuel injection guy so I'm shooting in the dark lol). Carbs need what, like 5-8psi? And most in tank pumps run 58psi
I think huck has something here. In description It sounds like you're running a carb but your using the tbi fuel pump. Is it regulated?
 

Ricko1966

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Yes you have too much fuel pressure, a tbi pump is going to be about 15 psi, a carbureator needs about 5. Your overfilling the float bowl and the bowl vent is draining into the canister. You need a bypass fuel pressure regulator,I'd mount it down where the original fuel pump was. Easy plumbing there and you can runbsteel line all the way from the regulator to the carb. No rubber hoses to leak on top of the engine.
 

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