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

soulvoid21 · Post by **soulvoid21** » 21 Mar 2017, 15:39

Hey Guys,

Having an issue of black smoke at startup and hard starts, cold or hot, but worse when below freezing. Believe it to be the fuel pressure damper, and have it, except I can't find it on the car.. I looked on the Volvo Parts Store Page and it said it's supposed to be on the bottom of the fuel rail, I haven't pulled the rail yet, but I can't see or feel it. I would think you could at least feel it without pulling the rail.

This is the part I ordered. Just want to make sure I'm going about this right before I pull the rail for no reason.

https://www.fcpeuro.com/products/volvo- ... vo-9186278

Thanks!
Sage

Post by **abscate** » 23 Mar 2017, 20:11

It's tucked under the rail, hard to see.

It's rarely the cause of starting and running issues.

Post by **mrbrian200** » 24 Mar 2017, 12:24

It's not necessarily on the rail. Not all VINs have them and it appears that it was either deleted, moved to the fuel tank/pump assembly, or replaced by a mechanism mounted internally within the rail (see below) sometime around MY04-05. MY06 vin59 (federal 2.5LPT) does not have one. I wouldn't necessarily expect MY07 to have one on the rail either, but might depending on which equipped engine/emission standard (federal or Cali) etc.

->I have noticed inside the fuel rail on mine (MY06) appears to be some sort of spring loaded mechanism which I suspect *may* be a functional replacement of the external damper you're looking for. I don't know for certain that this is a pressure damper, but I can't for the life of me imagine what else it could possibly be.

Also note, on these engines where a damper is present on the rail it is not modulated with a nipple to manifold vacuum (the back side of the diaphragm/spring is sealed). A failed damper which would be a function of the internal diaphragm springing a leak doesn't result in excess fuel (leak) into the intake manifold/black smoke you are seeing. On an '07 momentary black smoke/hard starting (both cold and hot) more than likely points to leaky fuel injector(s).

You're confusing a FP damper with a rail mounted fuel pressure regulator that predates modern electronic PWM controlled fuel pumps (which usually utilized a vacuum connection to the manifold to modulate fuel pressure as a function of manifold vacuum or lack thereof) that could flood an engine if the internal spring loaded diaphragm developed a leak.

soulvoid21 · Post by **soulvoid21** » 24 Mar 2017, 15:59

Thanks for the explanation on that. I wasn't sure if it was possible that they removed it or not. Looks like I'll be sending that back lol.

Maybe I can get some help sorting out this starting issue. It's very strange and is temperamental. I've already changed both cam and crank sensors as I was getting a crank code, both with genuine Volvo from FCP. It left me sitting in the driveway the day they were delivered to my door, what luck, right? Seemed to fix the issue for some time. Then randomly one day the hard starting came back, and has been giving me issues ever since (about 1-2000 miles I'd say). No codes either.

As I said, hot or cold it will do it, but much worse when below freezing, assuming because the battery gets weaker. I get a lot of visible black smoke when it's below freezing too. When it's warm, I get either a very tiny amount of smoke or none at all, none most of the time. It will also idle very low and stumble to keep itself running for a few seconds, then slowly come up in RPM to the 700ish idle range. If you tap the gas a bit, it will jump up to it's normal 1500rpm cold idle like it should, then just drop to the 700 idle again, instead of the typical 1500, 1000, then 700. It'll run perfectly fine once it idles up.

It has 118k miles at this time, and I bought it with 99k. Engine was replaced under warranty by Volvo for an oil consumption at 54k, car was purchased and confirmed at the dealer, but I don't have any other issues than this. MPG is normal, I average 20-22, but I'm a bit of a lead foot. Plenty of power and never any hesitation, stalling or anything.

I haven't pulled the spark plugs or anything, though I did check for anything visible and didn't see anything wrong. Made sure the air filter wasn't clogged, the basics. I'm not getting any ticks or anything either that would point to a bad injector, only odd noise is a little bit of belt squeal, though it's very faint, may be more of an old bearing squeal. Makes me think though, I can feel a noticeable change when the A/C compressor engages at idle. Starting issue doesn't change with A/C on or off though, I have tried that.

Sorry for the long post, trying to include as much info as I can!
Thanks!
Sage

soulvoid21 · Post by **soulvoid21** » 27 Mar 2017, 11:58

mrbrian200 wrote: ↑24 Mar 2017, 12:24 It's not necessarily on the rail. Not all VINs have them and it appears that it was either deleted, moved to the fuel tank/pump assembly, or replaced by a mechanism mounted internally within the rail (see below) sometime around MY04-05. MY06 vin59 (federal 2.5LPT) does not have one. I wouldn't necessarily expect MY07 to have one on the rail either, but might depending on which equipped engine/emission standard (federal or Cali) etc.

->I have noticed inside the fuel rail on mine (MY06) appears to be some sort of spring loaded mechanism which I suspect *may* be a functional replacement of the external damper you're looking for. I don't know for certain that this is a pressure damper, but I can't for the life of me imagine what else it could possibly be.

Also note, on these engines where a damper is present on the rail it is not modulated with a nipple to manifold vacuum (the back side of the diaphragm/spring is sealed). A failed damper which would be a function of the internal diaphragm springing a leak doesn't result in excess fuel (leak) into the intake manifold/black smoke you are seeing. On an '07 momentary black smoke/hard starting (both cold and hot) more than likely points to leaky fuel injector(s).

You're confusing a FP damper with a rail mounted fuel pressure regulator that predates modern electronic PWM controlled fuel pumps (which usually utilized a vacuum connection to the manifold to modulate fuel pressure as a function of manifold vacuum or lack thereof) that could flood an engine if the internal spring loaded diaphragm developed a leak.

After reading your response once again and thinking about it, fuel injectors would make sense. It would explain everything except the strange idle conditions, but that could be the computer trying to compensate, again, no codes or lights.

It's very strange, because as I said in my other most recent reply, it's very temperamental. The last few days have stayed above 40F, and I have not had issues starting since the 24th. Has been firing up perfectly every time. I'm not sure if it's common for a leaky injector to act this way, if it can be a come and go thing. I'm just a DIY guy and haven't had much experience with fuel delivery.

I'm not sure what all I can do to confirm if this is the issue or not. I've read that I could pull the rail with the injectors still connected, and turn the key on and watch if any leak when the pump primes the system. Is this pretty much my only option? It seems this wouldn't work too well as my issue is temperamental. Is there anything else I can try other than just firing the parts cannon at it? Lol. To replace injectors isn't cheap obviously, so I don't want to waste the money if I don't need.

Post by **abscate** » 27 Mar 2017, 16:17

Pull the plugs, let's have a look at them

Fuel systems are really reliable.

soulvoid21 · Post by **soulvoid21** » 28 Mar 2017, 08:44

abscate wrote: ↑27 Mar 2017, 16:17 Pull the plugs, let's have a look at them

Fuel systems are really reliable.

Will do this weekend, if weather permits. I'll take a picture of them if they seem normal to me.

Thanks again!

soulvoid21 · Post by **soulvoid21** » 28 Mar 2017, 08:45

abscate wrote: ↑27 Mar 2017, 16:17 Pull the plugs, let's have a look at them

Fuel systems are really reliable.

Will do this weekend, if weather permits. I'll take a picture of them if they seem normal to me.

Thanks again!

soulvoid21 · Post by **soulvoid21** » 28 Mar 2017, 08:45

I don't know why that made a double post lol, sorry.

Post by **mrbrian200** » 28 Mar 2017, 20:36

Looking at the plugs is a good start. I seem to recall experiencing some similar though not quite as severe symptoms on mine a year ago, and went down the same path (initially suspected a failed pressure damper but then determined there isn't one).

In my case with new plugs ran it ran slightly better but noticeably rough/uneven idle quality persisted. Couldn't trace to a specific cylinder I bought two new coils and switched them out with the originals 2 at a time to no avail.

Problem ended up being a combination of ring terminal grounds (grounds the coil packs primaries - the terminal wire crimps are prone to oil contamination if you have a leaky oil filler cap seal) and a couple wonky injectors that I suspect was due to contamination from POs neglecting to change the fuel filter. At 85k it was still had original filter, which should have been changed at least once by that mileage. Or from mostly sitting for about a year before I bought it. I have read somewhere Bosch gen 3s don't like that. One of the reconditioned injectors I got hold of was leaky and caused hard starting/long crank time/black puff of smoke at startup. The injectors I got were sold/listed for a GM 8cyl (same injectors) so with 3 spares in the box the leaker was off/replaced within a couple hours, and because it was switched quick for no additional $ I practically forgot about that.

Should you end up venturing down the reconditioned injector path there's a bit of roulette inherent to used injectors. I highly recommend acquiring more than you actually need. More often a set of 6 or 8 listed for some other make/model will be the same price or less than 5 listed specifically for your Volvo...because it seems the second you 'say' you own a Volvo the price goes up

but mostly

So long as the Bosch PN matches you're good. Bosch gen 3 injectors are a common upgrade on many older cars for people looking for better WOT performance and/or a finer atomized spray pattern/ improved fuel economy and emissions on vehicles originally equipped with Bosch gen 2's. I didn't beat up the seller over it for $70 or $80 I ended up with 5 perfectly good ones on the car + 2 spares out of 8 and was still happy.