Boost pump check valve stuck closed

[edclee]

This has happened to me twice now. This type has a manifold on each end and the fuel can be drawn through the check valve in the flow direction and does not go through the manifold because the boost pump itself will not pass fuel in either direction unless the pump is running. If the boost pump is turned on it sucks the fuel from the intake side of the manifold and pumps it through to the other side manifold and up to the outlet. That pressure also tried to go back through the check valve to the tank but the check valve has a delrin ball that will sit on a conical seat, preventing the boost pump from pumping back to the tank and only to the outlet to the engine. The check valve is the smaller cylinder of the two in the picture.
This is the second time the check valve stuck and would not pass any fuel. Only the boost pump will get fuel to the engine. I took it all apart and all looks fine, cannot get it to stick, works fine after disassembly and reassembly. Put it in the aircraft and it works fine.

Has anyone run into this before?

 

[Ralph Inkster]

I see the current EFII boost pump module’s check valve component is now a pretty blue color. Maybe they updated the innards too. Give them a call.

 

[RV7 To Go]

This has happened to me twice now. This type has a manifold on each end and the fuel can be drawn through the check valve in the flow direction and does not go through the manifold because the boost pump itself will not pass fuel in either direction unless the pump is running. If the boost pump is turned on it sucks the fuel from the intake side of the manifold and pumps it through to the other side manifold and up to the outlet. That pressure also tried to go back through the check valve to the tank but the check valve has a delrin ball that will sit on a conical seat, preventing the boost pump from pumping back to the tank and only to the outlet to the engine. The check valve is the smaller cylinder of the two in the picture.
This is the second time the check valve stuck and would not pass any fuel. Only the boost pump will get fuel to the engine. I took it all apart and all looks fine, cannot get it to stickView attachment 65634, works fine after disassembly and reassembly. Put it in the aircraft and it works fine.

Has anyone run into this before?

I would appreciate you letting us know what you find out. I have the same system, which has not yet seen fuel, installed in my under construction 8. I am going to use the Airflow Performance maintainable 40 micron prefilter instead of the one you have in the picture.

 

[edclee]

I see the current EFII boost pump module’s check valve component is now a pretty blue color. Maybe they updated the innards too. Give them a call.

I have the nice blue one already. The pic I showed was from aircraft spruce.

 

[Walt]

You running 100LL or auto fuel? I have the same pump, so this interests me, never had a problem though.

 

[edclee]

Running a mix of high test non ethanol and 100LL

 

[edclee]

Flew the airplane again today and it’s working fine. Of course it was about a year ago that I had the problem the first time and the system has been installed for 6 years

 

[Walt]

Please let us know what Robert says. I probably would have replaced the valve the second time it failed.
This is a really important part of the fuel system!

 

[edclee]

Please let us know what Robert says. I probably would have replaced the valve the second time it failed.
This is a really important part of the fuel system!

Robert says there are no repair parts available for it, but they can repair it at their place. The overhaul inlcudes all new parts and costs $292 total including return shipping. If I didn't already have it back in the plane I would send it now, but it is in the plane and working. From a safety perspective, It worked fine when the boost pump was on so if it stuck in flight I would do what I did this time and turn on the pump. My EFIS is set to warn me of the loss in fuel pressure to 20psi, so the engine never runs out of fuel pressure. Of course I always run the boost when taking off or landing. If it DOES stick however, I am down to a single point failure.