Changing out a stock fuel pump module on a 2002 Damon Daybreak with P30 GM chassis and an 8.1L (496Ci), motor home. Fuel pressure specs were in range at idle for 35 minutes, but test drive proved fuel pressure dropping as fuel in the tank got warmer with fuel returning to the tank and/or pump motor/georoter in the pump, temp going up. 56psi cold key on, 55 running 3000 RPM with load coldthen after 30 miles, 52 psi loaded at 2000 RPM, and 42 psi at 3500 rpm. 3800 RPM saw 38 PSI of fuel pressure. Pump is supposed to be rated at 150+ GPH so it's time for an update....
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