Engine/Transmission (1998.5 - 2002) Lift Pump Cavitating?

[cap-n-cray]

I had a lift pump failure at 36K. Replaced the lift pump. I took apart the failed lift pump and there was some wear. It still runs, but it's not going back into my truck.



I did a search and didn't find too much about cavitating. Could cavitating the lift pump be causing it to fail? Everyone by now agrees that the lift pump should be located by the fuel tank. A lot of members are running pusher pumps. Larger fuel lines seem to help. Less resistive?



Is the lift pump sucking from a small fuel line and restrictions from the tank, cavitating the lift pump and causing it to lose its lubrication and fail? If the lift pump runs too fast could that be causing the pump to fail? Could the pump be surging when it cavitates causing excessive wear?



I know that in a boat when you cavitate the prop the engine speeds up. You can over rev the engine when this happens. Could a cavitating lift pump wear out excessively?



I found this:



Cavitation – heart attack of the pump



Thus fundamentally, cavitation refers to an abnormal condition inside the pump that arises during pump operation due to formation and subsequent collapse of vapor filled cavities or bubbles inside the liquid being pumped. The condition of cavitation can obstruct the pump, impair performance and flow capacity, and damage the impeller and other sensitive components. In short, Cavitation can be termed as “the heart attack of the pump”.



Quote is from this Site .



Any thoughts?



Cary

 

[Gary - K7GLD]

In an external LP test I was running on a Frantz fuel filter, I found that significant obstruction to fuel flow CAN cause the LP to go into full-cavitation mode, and once in that mode, flow would NOT resume until the pump was fully shut down and restarted. Circumstances that MIGHT cause fuel flow obstruction and subsequent cavitation are a plugged in-tank filter, plugged regular fuel filter, or pinched or restricted fuel line. As far as the cavitation causing the pump to actually fail, *I* seriously doubt it - there is likely still enough fuel inside the pump to keep vanes and pump wall lubed, and motors such as used in these pumps commonly are operated totally dry in other applications, such as windshield wipers...