98 S70 Base Fuel pressure loss and P0172

tharde · Post by **tharde** » 11 Jun 2015, 04:57

98 S70 is throwing P0172 code and needs two cranks to start after sitting. Is it possible that the two issues are related? Would the fuel pump check valve show up as a vacuum leak? Any help would be appreciated.

Post by **Ozark Lee** » 11 Jun 2015, 07:57

In theory the two are unrelated but if the fuel pressure is low while the engine is running it could run lean and limit out, causing the P0172. I would get a fuel pressure gauge on the rail and see what you have for sure.

...Lee

tharde · Post by **tharde** » 12 Jun 2015, 12:30

Thanks, Lee. I'll check it out. It runs fine after starting, but could be running lean. The CEL usually comes on after about 30 mi or so.

Post by **abscate** » 12 Jun 2015, 14:52

Isn't the fuel pressure regulator vacuum driven on the pre 1999 cars? Common point for both symptoms?

tharde · Post by **tharde** » 22 Jun 2015, 14:12

Figured out that the fpr on this car IS NOT in the fuel tank, as suggested for a returnless system. It is in line with the fuel filter on the engine side; both are located by the right rear wheel. The fpr gets its vacuum from the purge valve line to the evap canister via a y-connector; this vacuum line had been previously cut near the engine and had been repaired. The front side (toward engine) of the fpr has a vacuum line and the back side (toward fuel tank) has a double walled fuel line (hard plastic covered by rubber). I'm going to replace the fpr and hope that fixes the problem.

Post by **McKennaR** » 10 Oct 2017, 11:32

Sorry to resurrect a zombie thread, but I wanted to perhaps provide some closure to people who find this thread by googling and wonder if replacing the FPR fixes the symptoms in the original thread

For my car (98 S70 n/a base) replacing this FPR (also called a "CPL" or Capillary Pump Loop in Volvo literature) located just forward of the fuel filter fixed the exact same symptoms that the OP describes (long cranking, weak starts, etc).

I tried asking around for 9445592 at a few Volvo/Euro parts outlets, nobody had one. I tried sourcing just the FPR itself (Bosch p/n 0280160556) but couldn't find a new unit in the US. I ended up googling 9445592 and finding it on CarID, of all places, and it came with the Bosch FPR (0280160556) on it.