What do I do with the vent port on my sending unit?

What to do with the vent port on a fuel sending unit. We get asked very often what the purpose and what to do with that 3rd vent port on fuel tank sending units.  What does a vent on a fuel tank sending unit do? A vent is an important part of your fuel system as temperature changes occur either from outside environment
What to do with the vent port on a fuel sending unit. We get asked very often what the purpose and what to do with that 3rd vent port on fuel tank sending units.  What does a vent on a fuel tank sending unit do? A vent is an important part of your fuel system as temperature changes occur either from outside environmental factors or the heat introduced into a system from operation of the fuel pump the fluid and vapors within a tank expand as fuel system temperatures increase and retract as the fuel system temperature goes back down.  Can I cap off my fuel system vent? NO, you must allow the fuel system a way to relieve system pressure and equalize the pressure with the surrounding environment. The only way to get around utilizing the fuel sending unit vent is by running a vented gas cap in it's place but at the end of the day the system needs a vent.   What do I do with the vent port? On a factory system this vent likely vented out to a charcoal canister which kept fuel vapors from stinking up the garage. Most aftermarket builds have had this system removed entirely in which case you can install a roll over valve onto the vent port. A rollover valve will prevent fluid from leaking out of the gas tank in case of a vehicle rollover. See HERE for our rollover valves.  Symptoms of a clogged fuel tank vent.  Some symptoms that you may experience if your vent is blocked on your fuel tank.  Reduced fluid fill volume Reduced power levels at high throttle Pump starvation and/or loud fuel pump In extreme cases the tank may collapse No start/no prime on the fuel pump As you can see something as simple as a vent can cause a number of issues with your vehicle.   

vacuum in the fuel tank - Dodge Diesel - Diesel Truck Resource Forums

In the Tank - 240 Volvo Tank Pump and Sender

CPP Fuel Tank, Fuel Injection-Ready, Set, 57% OFF

Package includes 1 x fuel tank vent valve grommet, 1 x fuel tank vent valve It's an aftermarket replacement part,Not OEM one Durable plastic

Fuel Tank Vent Valve & Grommet Kit,Fuel Tank Vent Valve Compatible with Jeep Wrangler, Cherokee, Grand Cherokee,Dodge Ram Van,Chrysler Cirrus,Replaces

* A duct window kit designed to pair with inline fans for ventilation to the outside environment. * Constructed for exhaust and intake purposes to

Window Duct Kit, Adjustable Vent Port for Inline Fans

SEE BANNER FOR CURRENT LEAD TIMES, WILL FIT YEARS 63-72 * Pictures show Rollover Safety Vent and Sending Unit Options installed., -Tank Dimensions

63-72 C10 Side Fill NON EFI Tank

CPP Fuel Tank, Fuel Injection-Ready, Set, 57% OFF

CPP Fuel Tank, Fuel Injection-Ready, Set, 57% OFF

Gas tank venting/Fuel sending unit

Everbilt 4 in. Dryer Vent Duct to Wall Connector EZCNHD - The Home Depot

Vent tube on Gas Tank Sending Unit?

Multiple Pocket Car Phone Holder - designed and developed in 2004, the High Road DriverPockets is a cell phone holder that hooks onto air vents on the

High Road DriverPockets Car Phone Holder Air Vent Pouch and Front Seat Organizer with 3 Pockets, Hanging Hooks and Charging Port

CPP Fuel Tank, Fuel Injection-Ready, Set, 57% OFF

P/N 18071 & 18073: 82-92 Camaro Stealth Fuel Pump200 & 340 LPH pump options, billet hat and 0-90 ohm sending unit High performance replacement for

82-92 Camaro 200 & 340 LPH Fuel Pump & Hanger

Caring for Your UreSil® Thora-Vent™ Memorial Sloan Kettering Cancer Center