high fuel pressure 1999 v70r

fairmont50 · Post by **fairmont50** » 29 Apr 2026, 15:32

Does anyone know the routing for the vacuum line that goes to the fuel pressure regulator on my 1999 v70r? I have been fighting a high fuel pressure problem on it for longer than I would like to admit. It runs fine but is pushing the feed line out of the fuel rail on occasion. I made a bracket to retain the feed line (genius, I know) but now it is pushing the damper out and leaking there. Near as I can tell, it is either the fuel pressure regulator or a pinched or broken vacuum line going to it. I believe the FPR is above the tank on the passenger side, I have not had a chance yet to get the car on the lift and verify that though. The pressure is about 55lbs at idle, as I understand, it should be closer to 40lbs.

Thanks

Post by **abscate** » 29 Apr 2026, 18:47

55 psi is ok for a 1999, it’s a “ return lacking” fuel system

The regulator sits above the tank. The evap line purge line is used as a vacuum source for the FPR

Vova585 · Post by **Vova585** » 29 Apr 2026, 20:20

Agree with abscate. 3.7 bar system might be slightly too high for usual 3-3.5 bar systems, but should not cause much issies. Possibly the car was fitted with aftermarket fuel pump with higher "turbo rating". In terms of "genius", you are almost certainly one. If I remember correctly the system should have a metal clip as safety measure for fuel line connector to the rail. Go to volvo parts store and look into parts diagram. You might be able to find proper part number. Please make a photo of areas of concern and some gurus here will be able to provide with more info.

Post by **scot850** » 30 Apr 2026, 07:26

My car ran at 59 psi (like a P1/P2) when Volvo checked it for me after I fitted a new pump around 10 years ago.

Neil.

fairmont50 · Post by **fairmont50** » 30 Apr 2026, 17:55

Thanks everyone for the replies. I had thought that 55psi of pressure was not enough to see the damage to the fuel rail retention clip that I was seeing. It is bending the ears back and pushing the o ring out at seemingly random times. Your replies made me think of the secondary check valve that I had put in ~4 years ago to deal with a fuel pump problem at the time. I have since put in a used pump from a v70xc that I cut out of a car in Sacramento. The check valve would likely work fine on a car with a regulator on the fuel rail where is belongs. But on a car with the regulator at the tank, during a hot soak event the pressure will spike until it cools off since there is no where for it to go. Who knows how high the pressure is going in this situation but it is obviously very high. Usually, the problem was showing up after parking the car hot for a bit. Planning to replace the check valve with a splice tomorrow and see how it works.

Thanks again,

Chris