Fuel pump check valve for 94ATX

[ISHOU]

When I replace my fuel pump on my 94 ATX in the near future I want to replace the check valve on the end of the return line because I've read here they can go bad causing a hard start when the engine is hot. I go to Ford and the guy asks me is my return line 7.2 mm or 5.7mm because there are two applications. I have no idea about the diameter of my return line. Anybody have some insight on this. The part was only $5 so I could buy both but he said it's special order and I couldn't return the wrong one.

 

[LT]

Purpose of the check valve is to maintain fuel pump prime and fuel supply line pressure after engine is shut off. Check valve is normally closed, opens when pump pressure exceeds the check valve spring load. Is mounted on the in-tank fuel pump.....you sure you want to mess with this???

 

[DJ SHO]

IF you expereince hard starting now, or think you will in the future, don't worry about the check valve. I think it's with the pump assembly. I had hard starting (loooonnnggg cranking time) before I replaced the fuel pump. Move up to something like a 155 lph and u should be set. It will take care of the long crank times too, if u r having that problem.

 

[sdpatt]

I believe that he is referring to the fuel return line check valve that helps to keep a small pressure on the fuel return line. When this valve wears out, there is a noticeable bubbling of fuel vapor up through the gas in the tank when a hot engine is restarted. It can cause a loping idle until cool fuel reaches the return line. Search the Forum on the key words as I have previously posted the part number and there have been pictures also posted.

The fuel pump check valve is internal to the fuel pump and does help hold the fuel line pressure to the fuel rails after the engine is shut off. That valve is not replaced separately from the pump.