LS tank Vent 72C10 LWB

[rmv23887]

Adapting stock pump to stock (suburban/Blazer) steel tank behind axle. What do I need to do about vent? Have one(vent) on stock tank and one on pump.
Any input?

RandyV

[BR3W CITY]

Assuming you mean adapting the sending unit? The pump itself is just the little pump motor, not the whole basket assembly.

Either way really, you've got a few choices;
a) just stick a breather on the vent or run a line to a breather.
b)actually run the vent to a charcoal cannistor/evap (this is the factory config)
c) block it off and run a vented cap.

As long as there is some way to vent pressure, it doesn't really matter how.

[rmv23887]

No, i am modifying tank to accept the stock fuel pump out if donor(2003 Silverado) Tank has a vent pipe, fill neck and a sending unit (including cab fuel pickup) The fuel pump has feed, return and a third connection. I assume the 3rd port is for the canister, i am asking how out to vent, pump or tank vent.

[BR3W CITY]

I'm not sure you read my post through.



That whole thing is the pump assembly, the pump itself is only the lower portion, while the upper portion contains the sending unit (the arm) and the 3 ports.

You do not need a vent on the tank AND on the pump assembly. The third port is EVAP. If you re-read my post, it explains your options. You can hookup the EVAP like o.e., or just run a vent or vented cap.

Vehicles that use an external pump (so, not having the whole sending unit assembly) will sometimes have a vent on the tank which will either vent to air through a breather or a charcoal cannistor, or just use a vented cap.

You do not need both, tho they both pretty much serve the same purpose.