ulmapache
Registered User
Does the mechanical fuel pump act as a check valve to prevent fuel from draining out of the filter? If fuel is draining out (filter not completely full, half full) does that indicate a failing fuel pump? Thx...
fuel pump
- Thread starter ulmapache
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nelstomlinson
Full Access Member
No, surprisingly enough, the mechanical fuel pump isn't a check valve. Any sort of air leak in the return system will let the fuel on the supply side run back down into the tank. There are several sources for check valves, like Classic Diesel Designs. A half full filter is more likely to be a return leak than a bad fuel pump, especially if you can climb a hill without seeing fuel starvation issues.
Do you have a little puddle of fuel anywhere on top of your engine? That points to your problem, if you do.
If you don't have a tell-tale puddle, consider the possibility of air intrusion either on the suction side of the pump, between the tank and the pump, or on the pressure side, mechanical pump to filter or filter to injection pump.
Do you have a little puddle of fuel anywhere on top of your engine? That points to your problem, if you do.
If you don't have a tell-tale puddle, consider the possibility of air intrusion either on the suction side of the pump, between the tank and the pump, or on the pressure side, mechanical pump to filter or filter to injection pump.
A leaky hose at the lift pump can cause air intrusion too. I had that problem.
ulmapache
Registered User
Thx for the replies!!! No puddles, filter is full,..so it is definitely the glows...thought I was going to do these this weekend, but the guy doing our floors has a cancellation...we get our wood floors sanded and refinished...starting this Friday...move all furniture etc. Takes a week...so maybe next week i can do those glows...
!!!!
!!!!Booyah45828
Full Access Member
A mechanical fuel pump should act as a check valve, but after how many years and thousands of miles it might not perfectly seal anymore.
There are actually 2 check valves inside, one for the inlet, and one for the outlet.
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