Big Fuel SumpBig Fuel Sump This sump was designed by us for when you are running two separate fuel supply pumps. For example, when running a 2011 Current 6. 7L Power Stroke with dual HP Fuel pumps you must run 7 10 PSI into the CP3 and 70 PSI into the factory CP4. This requires two separate low pressure fuel pumps (FASS or Airdog) one at 7 10 psi and one at 70+. The dual outlets allow you to connect both to one sump. You can return them both into the single return