2.5T (S60) Observation regarding engine vibration Topic is solved

[mrbrian200]

New to me '06 S60 2.5T FWD 81k miles (my first Volvo -and- so far so good!) Picked up as a fixer-upper primarily just needed the standard round of front suspension work (control arms/bushings/mounts etc)

Got the low fuel pressure CEL last week as the weather dipped to below 0F/-20C, live data showed erratic pressure reading anywhere between 0-380kpa (0kpa with the car running + good power at WOT was an easy diagnosis).

I have noted more vibration at idle than I would normally expect for this type of vehicle. I understand this is "typical". Mounts/bushings etc are all good I replaced a couple that were worn with new rubber.

Yesterday the new FPS arrived and I replaced it (and the filter that looked original) . Woohoo what a difference. Car really "zooms" now with excellent/linear response in relation to the pedal. Now this is the interesting thing I observed: the engine vibration felt through the steering wheel/chassis tamed way down (felt really good - just enough for feel/feedback) for about 15 miles, then returned.

I did not bleed the system of air thoroughly- just keyed to position II a few times to pressurize the system, opened the Schrader on the rail but wasn't nutty about getting every last bubble of air out. So for the first few miles there would certainly have been some air trapped in the top of the rail (acting as a pressure dampener!). So I'm working up a "theory" that either the dampener in the fuel line is either inadequate, or bad. I am presuming these are a diaphragm to atmosphere design, possibly the diaphragm material stiffens and loses effectiveness or is just inadequate/poorly placed (needs to be up closer to/or integrated right onto the rail)?

[harryhendo]

In my experience, I've never bled the fuel rail. After reinstalling the fuel rail, the engine will run roughly for about a minute, then everything will settle down nicely. It could be an issue with the fuel pressure regulator, which is usually evidenced by poor starting and low idle, which does cause vibration. Is the idle RPM right where it should be?

[oragex]

As above, also how is the fuel pressure as of now?

[mrbrian200]

Edit: pressure at idle = 43.5 is normal. Knew it was a PWM pump assumed it maintained constant pressure. See "learning experience" reference below. You can skip the bulk/paragraphs to the live data does anything stand out I don't really know this car yet / what those should be.

In about a year or two I'll know this one in better than many dealer mechanics (so many of which are just following the functional equivalent of a flow chart but don't barely understand how any of it actually works).

Might be more to this than I thought, but maybe not. That 15 miles of excellence was coming out of a heated garage now that I think about it. I didn't check the pressure at that time I thought that was "done". Idle quality degraded to "hard but smooth" thereafter. Now one day later, parked outside, even colder, and 30 more miles, though the pressure reading isn't fluctuating erratically as it was before replacing the FPS and filter, diag tool shows pressure (steady) at 43.5 psi which is low. Idle quality also a bit rough until the engine bay warms a bit (was doing this-not new today). Note "hard but smooth" as I describe applied to nearly all of the '04-'07 S60s I test drove back in October/November-- you know, the steering wheel/chassis while standing in gear with the brake feels..uh..Stimulating (test drove 5, the only one that "purred like a kitten" in this respect was a '06 with 35k miles that looked garage kept (history showed Volvo dealer service through all 10 years/one owner). All the others had varying mileage and histories between 55k-110k) and were all more or less equally "stimulating" at a standstill. This one was in the middle (between the 35k one, and all the others)

My mistake on the first post: I had seen/confused information regarding other model years and have since corrected my knowledge that the EFI damper *is on the rail* on this one.

The times I saw pressure at normal (before the FPS/filter change, readings were erratic but peaked at 57-59psi) was when temps were well above freezing. I'll nail this eventually. I've dealt with far worse over the years ('95 Cirrus!). However, yesterday for that short bit the car demonstrated it is still capable of purring like a kitten.. the reassurance being when I do nail this down it will be obvious.

These are the live data I have access via my scan tool (elm327 to a laptop). Software I am using is somewhat limited but spits out the basics. Doubt it, but if anyone with more experience with these specific models can spot a specific combination of values that spell "eureka!" you might save me some time. (I'm new to Volvo, but fairly competent overall, every make/model presents "unique issues" and thus a learning experience). I haven't paid garage mechanic since around 1990 I've always been able to sort things out (sometimes with a bit of time and hair pulling a '95 Cirrus comes to mind).

**cold start, idling in park**
Fuel System 1 Status, closed loop
Fuel System 2 Status, unused
Calculated Load Value, 22.0%
Coolant Temperature, 107F
Short Term Fuel Trim (Bank 1), 25.00%
Long Term Fuel Trim (Bank 1), 3.13%
Fuel Pressure (gauge), 43.500 psi
Engine RPM, 668 r/min
Vehicle Speed, 0.0
Timing Advance, 5.0 deg
Intake Air Temperature, 37F
Air Flow Rate (MAF sensor), 0.6 lb/min
Absolute Throttle Position, 13.7%
O2 Sensor 2, Bank 1, 1.275 V @ -92.19% s.t. fuel trim
Time Since Engine Start, 0:4:19
Distance Since MIL Activated, 0 miles
Warm-ups since ECU reset, 52 (I didn't do this likely was the dealer or previous owner/auction)
Distance since ECU reset, 1566 miles (subtract my miles leaves roughly the distance between auction in Ohio -> dealer in Indy where I found it)
ECU voltage, 14.000 V
Ambient Air Temperature, 18 F

Stored PIDs 3,10,11,29,30. Doesn't tell me "when" or the DTC when the snapshot was stored.
CEL not presently lit

I haven't yet ruled out the Damper and might open the rail to reintroduce air (remove the FPS drains the rail, restart, observe) but this time do it outside/good cold start. Mileage is definitely off. It got 37MPG on the highway drive when I drove it home from Indianapolis (100 miles). Since this started about 10 days ago I'm getting 28 at best highway, stop/go is awful, except for that short period of 15 miles/minutes where it was back up. There's no telling how fluid hammer might affect the reading off that sensor. In addition to peaking high, the rebound would be low, especially if it times just right with a subsequent injector pulse. I should probably pick up an old school gauge. Tools for me generally get bought if I need them. Fuel delivery problems I've dealt with on previous vehicles were "all or nothing", or more obvious (leak, sputters at WOT, bad ground, pump works again if you whack the bottom of the tank, etc.)

[mrbrian200]

Little more testing/driving today monitoring live data. Fuel delivery/FPA issue does appear to be fixed. 61psi at key position 2, idle and part throttle cruising 42-44 psi, spikes up under hard acceleration (I saw 51 at about 50% throttle). Roads aren't good enough today to do a WOT and hold it there I suspect if I did it would spike higher as it's supposed to.

Discovered this morning (little rough, hard start, 2 tries) kicked the throttle quickly a couple times and got smooth/normal idle. Did notice some surging and non linear pedal/power response.

I don't know which number on there is the date code. (see attached pic) No yellow sticker. Not sure that all applies to an '06?

If it does, was that an open ended recall or a "warranty extension" (likely on my own on an '06/now)

[jimmy57]

Throttle issue is over for 2002 MY for turbo and 2003 MY for non turbo on that model.

That is an electric throttle assembly and not a throttle module that was the culprit for the throttle issues.

[mrbrian200]

OK. Thx for the heads up regarding the TBA/TBM warranty/recall. Haven't managed to decipher the date code but judging by the bit of corrosion/dirt on the housing (matches other alum parts around it) it's certainly original. Similar/identical design Bosch TBA used in some Benz models found info on. Pretty simple inside really (DC motor, couple gears and a pot). This is the sort of thing I'm really good at. Either the pot is dirty, the DC motor builds internal resistance from dust/contaminants (most likely) or a bad motor winding (unlikely). Makes perfect sense it would get touchy in the cold with age. Probably a dry bearing shaft just pick it apart and clean it. If the bearing looks greased I'd say Super Lube/Synthetic+ PTFE should do the trick. Will report back but it might be a few days/week till I get to this. Want to finish up front suspension work first. Came with bad aftermarket axle shaft that spun/locked into the hub new hub arrived yesterday plus front struts waiting to go on. Control arms already done. CA Bushings were all torn up/ shaking like an earthquake and pulling hard to the right when I bought it. Its getting there... Talked the dealer down several thousand I'm not in over my head/ARV yet...but approaching that point, we'll see. If much more pops up I might end up in the hole yet on this one...

[zanzabar]

I have similar issues with my '07 2.5T V70. Have not gotten around to troubleshooting fuel system.

Any chance injectors are to blame? Perhaps a partial blockage got freed up for those 15 miles of bliss, then clogged up again?

[mrbrian200]

I don't suspect that no. I've experienced injector problems like that in previous vehicles I've owned. Symptoms I would expect to be different. (apparent miss/eneven on one cyl not generally "rough" across all) I wouldn't rule it out completely but based on symptoms it's near the bottom on my list. Looks like I just worked myself in a tizzy assuming I had one primary issue that wasn't resolved (fuel delivery/FPS sensor) when I actually had two issues - It just took me an extra day to realize that and move forward. The 15 mile moment of clarity (looking back) had nothing to do with air dampening effect in the rail. It was because I was working on it in a heated garage. The TCA was warm and working (you know metals shrink when cold, contamination+dust will bind up a dry bearing progressively as temp drops: consider a cheap AC floor fan as an example we have all experienced), together with my observation that its fine with warmer weather/engine bay I'm pretty sure I got it. Never say never though...

[JudgeRat]

Engine RPM, 668 r/min
Vehicle Speed, 0.0
Timing Advance, 5.0 deg
Intake Air Temperature, 37F
Air Flow Rate (MAF sensor), 0.6 lb/min
Absolute Throttle Position, 13.7%
O2 Sensor 2, Bank 1, 1.275 V @ -92.19% s.t. fuel trim

Guys, am I wrong, or is that idle speed hinky? (that's a technical term: hinky ) Isn't it supposed to be more like 700rpm? If that is the case, then this reading is ~4.5% low. I don't know enough to know if that falls into an acceptable variance or not. I'm just thinking that at that ambient temperature, I would expect it to be a little high, if anything, to compensate until the engine was completely up to normal operating temperature (a little over 4 minutes of running and it is only up to 107 degrees coolant temp). I did a quick search of the inter-web and found that a couple of folks that were seeing idle like that had done so when they had either MAF or PCV issues.