2007 S60 2.5T AWD Fuel Pressure Damper Location Topic is solved

[Massanka1]

The fuel pressure regulator is located in your fuel tank inside of the fuel pump assembly. It's no longer attached to the injectors rail.

[soulvoid21]

Alright, so I got my Fuel Pressure Gauge today. Seems the pump isn't priming all the way. 0psi when I connecting the gauge (obviously), cycle key to position II, it seems to only prime the system 4psi at a time, sometimes it doesn't prime at all.

While starting the engine, the pressure builds very slow as the engine stumbles, then levels out to 40psi and seems fine.

Leaving the gauge sit right now to see if it leaks at all.

[soulvoid21]

Alright, so here's my test numbers. It only seems to prime 4psi at a time when it's empty, and that's what's causing the hard start. I get the exact symptoms I used to when I empty the rail and try to start the engine right away.

During start: 4psi
While running: 42psi
At 2:24pm after shutting down the engine: 37.5psi
10 minutes: 32.5psi
20 minutes: 31psi
30 minutes: 30psi
40 minutes: 28psi

I also want to note that the pressure gauge I'm using, and the pressure readings from the computer is off by a random amount of pressure every time. Possible signs that the pressure sensor on the rail is going bad? If I turn the key about 15 times, I can get it to prime up to 35psi on the gauge, but no higher, and it will read 45psi on the scanner. It does help make the car start better as well, but not like it should.

[soulvoid21]

So today I pulled the Fuel Pressure sensor just to visual inspect it, and there didn't seem to be anything wrong. There was some corrosion inside the metal ring that it bolts with, I'm not sure if this is a ground terminal. But I clean it and the bolt up the best I could, but same issue.

I also crawled back under the car to check the fuel filter. I'm not sure that it was in this condition when I check it last, but I could have been mistaking it for my other car. Seems to have the same road grime and buildup as the rest of the body, and still had the factory wrap or tape (not sure what it is) on the connectors at each end of the filter.

I didn't want to unbolt and disconnect it as I don't have a replacement on hand in case something happens. But judging by it's condition, and after checking Volvo's scheduled maintenance, it's the factory filter. They only get replaced at 120k per the book. Will most likely order a replacement.

[soulvoid21]

Fuel filter

[soulvoid21]

Was out around town today with a client of mine after messing with the pressure sensor, and had the car almost leave me sitting. Took a solid two minutes to get it to start.

The strange thing is it wasn't consistent cranking of the starter/engine. It sounds like it's trying to make a full revolution, pauses at the same point like the engine is hydro locked on a cylinder and all of the lights dim like the starter is pulling all power from the car (assume it is), but will then continue and did this over and over, seeming to pause at the same exact point every time. It does this once in a great while, but never takes that long to actually start. Only does this when the car is hot as well. It's a nice 85F and about 80-90% humidity is my area today -_-

I left the car idle as I finished my trip around town instead of risking being stranded. Once I got home, I attempted to record what happens, but of course, it was starting normal, just with slight hesitation like always.

Keep in mind, I replaced both cam and crank sensors a few months ago. They maybe have 3k miles on them. No codes or CEL either.

Please help! lol, so extremely frustrating

[soulvoid21]

Awesome, I found a video of someone having the exact issue I stated above. Though my tach doesn't jump around nearly as much.



As stated, I replaced my cam and crank sensors with Volvo replacements about 6 months ago after the car left me sitting in the driveway. This fixed the problem for a very short while. Maybe a week before it came back and slowly got worse.

Someone in the comments mentioned that they had to have the flywheel and starter replaced. Something of note, when I pulled my old crank sensor out months ago, it seemed to be scraped a bit where it would get the readings from the flywheel. Not by dirt as it was shiny and clean, but seemed like metal on metal.

Another stated the fuel relay was the culprit, which I know is a common failure with Volvos. Both my 850s needed replacements, and one of them I had to replace twice. All of them for crank, but no start issues.

Should I take the time to pull my crank sensor out and check to see it's been damaged?

Someone else mentioned in the comments that the crank shaft could be loose, but I highly doubt that. The car runs perfectly fine under any type of load, and doesn't leak or burn any fluids, and doesn't have any type of knock, rattle or squeak.

[soulvoid21]

Finally received a CEL, code, and was put into Reduced Engine Performance mode for a few seconds. All cleared themselves and the car runs normal again, just still hesitates at startup.

Code was P0336 - Crankshaft Position Sensor A Circuit Range/Performance

No other codes or lights, was an orange warning light too, not red.

I just replaced this sensor but about 5k miles ago with Volvo brand parts from FCP, I did both cam and crank at the same time because the car left me sitting in my driveway.

Any tips? I really don't want to just throw another crank sensor at it.

[soulvoid21]

I'm going to start a new thread that is properly named, and has all the info in one post.

The original question to this post was answered. My car doesn't have a Fuel Pressure Regulator, the Fuel Damper is part of the fuel pump assembly.

Am now getting the Reduced Engine Performance at all times. Same code as above, no CEL or Red Warning light, and the car seems to be running at full performance, even with the message on the info center.

No stalling issues, and it will start after trying for about 10-15 seconds on average. I'm not driving the car daily anymore and haven't been for about 2 months, just on occasion so it's not sitting.

[jimmy57]

Actually the damper is a flattened brass tube inside your fuel rail on that 07. The device in sending unit/fuel pump cap is the pressure ventilation valve. Effectively the max fuel pressure regulator used only if PEM or fuel pressure sensor fails and pump is delivered full current. If the system controlling fuel pressure via pump current regulation has an issue then it goes to default full speed and lets the PVV regulate fuel pressure. Damper function is to suppress hydraulic hammer from pressure drop and rise of injectors flowing fuel and then suddenly closing and the fuel pressure would spike. If the spike was not handled then if the timing of next open injector was within pressure spike period it would deliver more than the desired fuel amount.