Can fuel pumps die a slow death

[racecar866]

I started a post few days back regarding a 944S that loses fuel pressure when you increase rpm's. A few poeple suggested fuel filter, vacuum, and regulator. Well the filter is new, the regulator is new, i dont see any kinked fuel lines, vacuum lines all hooked up ok. Starting to wonder if it is the pump, but I've never heard of a pump getting "weak" and not being able to keep up. When idling, the fuel pressure is fine. Any thoughts

[seaboltman]

generally its "enough pressure to run" or "not enough pressure to run" from what I understand. Do we have electric fuel pumps? If so i could be a loose connection for the pump.

[Ferrara_racing]

It could happen that way, usually they just go. It is an electric pump. A plugged fuel filter could cause simular symptoms..Good luck.

[mike944]

Sounds like a clogged filter to me. What happens is, as the RPM's go up, the computer starts asking for more fuel, and the injectors start opening for a longer duration. This dumps more fuel out of the injectors, than can be supplied into the fuel rail. Once the volume that the injectors are asking for, becomes greater than the volume supplied into the rail, the regulator can no longer bleed off the excess fuel to control pressure (because there is no excess fuel). That's why the pressure drops.


It could be a bad pump, but probably just a clogged filter. You might have to replace some of the rubber hoses when you change the filter, as the metal end fittings corrode pretty severely, and sometimes they can't be disassembled without destroying them.