LS tank Vent 72C10 LWB
 

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

Re: LS tank Vent 72C10 LWB
 

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.

Re: LS tank Vent 72C10 LWB
 

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.

Re: LS tank Vent 72C10 LWB
 

I'm not sure you read my post through.

http://d3d71ba2asa5oz.cloudfront.net...s/323-1229.jpg

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.