Fuel pump Check Valve

[volvolove]

UPDATE:
I finally ordered the check valve and installed it in the fuel line running from the tank as close to the tank as I was able. That is another story, as the fuel line is a rubber line, but inside of the rubber it is actually nylon. Anyway, after I installed it, I primed the line by turning the key on a couple of times. No problems. After a short jaunt, I shut the car down, and started it right back up. I did this probably 3 times just to feel it out. Then I went inside for roughly 10 minutes. When I came back, the ol girl wouldn't start at all. Before I installed this check valve, it would always start on the second try if not after the first try, and now it would not start no matter how often and for how long I cranked it. I crawled under the car to check my work. No leakage. I checked the fuel pressure on the fuel rail, and it sprayed me w/ plenty of pressure. The fuel rail never had pressure in it at all before unless the car was running, not even seconds after running.
After draining the pressure, the car fired right up. Then I drove it down the road to my house. Did the same thing: shut it down, started it up; several times. No problems. Went inside for about 10 minutes again. Came out, same problem. I released the pressure, and she fired right up. Now the third time I drove a couple miles, same thing with shutting it off and starting it right up but this time I went inside for an hour and came out and fired her right up. Went inside for another hour, came out and fired her right up again. Then I drove back home. Shut it down and waited about 10 minutes again, and no dice, she did not want to start. Then I cam in and researched on this webpage and started to write this post. After about 40 minutes, I just stepped out and fired her right up. WTF? I know I know, I can probably replace that check valve w/ a junction or replace the whole line, and be back where I started, but I cannot figure out why this would happen unless it messes w/ the fuel pressure regulator? I just read a post that said the regulator in the XC is back by the tank. Does the check valve need to be before that?

Thanks again

[MixEngineer]

Why not just REPLACE the old check valve instead of adding an additional? Or is the original check valve non-replaceable?

Thanks

[JRL]

Not replaceable, integreral part of the OEM fuel pump
If the poster installed it correctly and not backwards for instance, it should be fine.
We install ours right at the back of the fuel filter and we buy a NEW filter

[rspi]

Isn't the fuel pressure regulator suppose to hold pressure?

Also, the fuel pump usually does not build pressure unless you have the key in the start position. So, you can turn it to run 100 times and still have no pressure until you turn it to start.

[JRL]

Not true in 99s and newer

[shiloh51933]

Isn't the fuel pressure regulator suppose to hold pressure?

Also, the fuel pump usually does not build pressure unless you have the key in the start position. So, you can turn it to run 100 times and still have no pressure until you turn it to start.

Most fuel injected vehicles pump fuel once you turn key to on position or position II in this case. Check valve holds pressure while engine is off, bad check valve equals hard or no start during first crank of key/motor. But yes your also right, fuel pressure regulator does maintain steady pressure while engine is running. That's the reason they still run good even though the check valve is faulty, the pressure is constantly being maintained while motor is running.

[MixEngineer]

No, the fuel pump does build pressure just by turning the key to the position before Start. You can hear the pump come on without starting the engine. Maybe older models don't, but I know that from at '02 to '04 it does (those being the years that I have owned).