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Discussion Starter · #1 ·
I've been having the hard start issues described in several threads and it appears to be a failed fuel pump check valve. I've found several how-to's for installing in-line check valves on earlier model XC70s but nothing for P3 XC70s. Has anyone done this or can provide advice for where specifically to install a check valve? I don't really feel like replacing the fuel pump. Thanks!
 

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Fuel Check Valve

I have read enough about P3 to know if I ever have any symptoms of a fuel pump that I will first replace the sensor on the end of the fuel rail on the head. These are know to have problems and cause issues.

I've been having the hard start issues described in several threads and it appears to be a failed fuel pump check valve. I've found several how-to's for installing in-line check valves on earlier model XC70s but nothing for P3 XC70s. Has anyone done this or can provide advice for where specifically to install a check valve? I don't really feel like replacing the fuel pump. Thanks!
 

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Discussion Starter · #3 ·
I have read enough about P3 to know if I ever have any symptoms of a fuel pump that I will first replace the sensor on the end of the fuel rail on the head. These are know to have problems and cause issues.
I've encountered fuel pressure sensor issues on other Volvos and never had this symptom. Simple enough fix, though, so I might go ahead and try it. I know in another thread about this hard start issue the poster tried a new FPS and it didn't help. What I'm seeing in VIDA is an almost instantaneous drop in fuel pressure (which of course is read by the FPS) after shutting off the car. There's no external leak so from what I've read the likely culprits are the fuel pump check valve or a leaky injector.
 

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Yours may not be the FPR is you are monitoring it in VIDA. A 20 Oz bottle of Techron concentrate may help clean up an injector problem.
 

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Discussion Starter · #5 ·
Yours may not be the FPR is you are monitoring it in VIDA. A 20 Oz bottle of Techron concentrate may help clean up an injector problem.
Yes, I tried Techron (12 oz in 12 gal) thinking it might help the check valve if that was the problem but no difference. Maybe I'll hit it with a more concentrated dose to clear up any injector issues anyway.
 

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I saw yesterday Amazon running a $12.XX deal on a 32 oz size. It is in a container like gear oil. I have never seen that before.
 
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