Ok so we know that electric lift pumps are a good solution for various problems caused by the fact that the lift pump is at the engine. But a thought occured to me, might not a simple check valve just past the tank help out with air accumulation problems?

My thinking is that some of the trapped air might come from when the vehicle sits, and a little bit of a leak lets air into the system, and the fuel drains back towards the tank, but by putting a check valve there you would keep fuel from being able to do that, maybe reducing the risk of air buildup.

There is a BMW part that costs $7 and comes with the valve, hose, and clamps, its a pretty popular option for XJ people who have the in tank high pressure fuel pump check valve fail. I recently ordered 2 so I will post pics of it when it arrives.

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got a link handy to a forum or something where they are installing that onto an xj?

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Fumoto, Second gen fuel head,EHM, GDE eco tune, Airtex E7181M lift pump.

We already have a check valve in the fuel filter primer pump that prevents fuel from draining back to the tank from the fuel head.

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Has anyone observed that the check valve in the primer pump does stop flow back to the tank when not priming?

Locating a check valve in the return line from the injection pump might work better than one in the supply near the tank. The injection pump can handle some air if it doesn't lose its prime. By putting a check valve with low opening pressure in the return, the IP should retain its prime. A check valve in the supply would just be more resistance for the IP suction to overcome. This would make it easier for air to leak into the line between the check valve and the pump. The check valve in the supply line at the tank would, if it didn't leak, keep fuel in the line from the tank to the filter head. Fuel might still leak back from the IP to the tank via the return line, allowing the IP to lose its prime.

I agree with Wobbly, more negative pressure is not a good thing. You might be better off to put a solenoid near the fuel tank instead.

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