First of all I have the 2000 XC70 AWD Turbo.

The car is hard to start so I hooked up a fuel pressure gauge and discovered that as soon as the key is turned on pressure hits 30 psi. I start car and it runs around 30-35. When I turn off, the pressure immediately bleeds off to zero in a minute or so. This isn't right. Pressure should be maintained for quite a while after shut down. So, I'm pretty sure the fuel pressure regulator is on its way out.

Now the insanity begins. Lots of searching on all the Volov forums and VADIS for FPR location. VADIS says it's on top of the fuel tank for this year and model. Some people said it was on front axle (nope not there, I checked). So dropping the tank is a huge job to get to it.

But now more mystery is thrown into the equation. When I go to check on prices and part availability at the dealer, they tell me the FPR is actually built inline in the fuel hose that runs from the fuel filter to the engine ($410) yikes!!!

The part on top of the tank that I thought was the fuel pressure REGULATOR is actually called the fuel pressure SENSOR.

So my questions are 1) what is the function of the fuel pressure sensor on top of the tank? 2) would failure of this fuel pressure sensor cause the fuel pressure to bleed off after shut down or this is symptom a function of the fuel pressure regulator solely?

Anybody really understand this set up?