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Q: Please help with my Volvo

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Hey, 09 Volvo s80 t6 AWD, takes 2-3 tries to start in the mornings, i can shut it right off and then it will start no problem. Also very loud noise when revving (in gear or not, moving or not) for the first 20 or so minutes. CEL P0171 comes up sometimes but most times goes away after a bit of driving. Fuel Pressure at 60psi when running but in the morning turned ignition on psi went from 0 to 30 in 2 seconds and stayed there until I started the car. Any ideas?

My car has 125000 miles.
My car has an automatic transmission.

For your car, the specifications for your fuel pressure is about 30 psi to 60 psi depending on the load. Your fuel pressure should hold the pressure to the injection system overnight and only leak down about 5 psi from what it was when you shut off the car.

If the fuel pressure drops to zero or close to it in less than half an hour then you have a fuel pressure leak down problem. The leak down can be the fuel pump check valve or one of the injectors leaking.

The most common problem is the fuel pump not maintaining the pressure after shutting off the engine but do not rule out a leaking injector.

As for the noise, this may be the fuel pump whining to try and keep the increased fuel pressure up to specifications.

My recommendation is to have the system diagnosed by a mechanic, such as one from YourMechanic. We will have special fuel testing tools that are needed to check your vehicles fuel system along with the loud noise that you are hearing.

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