Fuel Pump Problem??
 

Has anybody else noticed that after awhile their 190lph HP does not hold pressure in the system for very long after it's turned off? The OEM held pressure for days on end. It has not caused a problem...yet. Just interesting.:ugh2:

My 255 does the same thing. Over-night the pressure on the gauge will be "0" before I start it.... No problem priming on start though, turn key, and it catches.....

Dave,

My MSD aux pump is the same way. I wondered about this too, but doesn't seem to be any problem, I feared leaking injector, but I've never had any issues that would indicate that to be a problem.

Mine leaks down in a min or two.

Glad to see I'm not alone on this. Must be the Walbro design/execution with clearances on the gears.

Comment. It may not be the fuel pump as pressure is trapped between the stock FPR and the fuel pump. The stock FPR is just a mechanical diaphragm.

No priming is needed as the fuel system is a closed loop. The fuel lines and rail are full of fuel, just not under pressure. When you hit the start switch the pump builds enough pressure rather instantly. Does not matter where the throttle is or what the timing is set at during start. All that is mapped by the ECU.

Yes, I guess it is possible that the FPR is getting weak, but it isn't worth the effort to find out yet. No problems at all, just noticed the pressure drop after sitting a couple hours. Used to be it would hold for days with the OEM pump. On the plus side, I didn't need to crawl under the dash to pull the relay last time I changed injectors. The car had been setting two days and the pressure was down to -0-