Not sure if we got a death sentence on '07 V6 XC90... fuel pump, prop shaft, 2-3 cats + more?

[chitownV]

Okay, I cannot remember your "color cars." Just say what year and engine as that carries a lot of information (you can put them in your signature too). Blue pill, red pill, don't know what is in each, lol.

If you are used to Hondas, then you will understand that you can get cat inefficiency codes when the spool valves, VTEC valves, start to leak oil because the camshaft to timing/fuel are off. The issue isn't changing the cats, but to fix a leaking spool valve. The cost, less than $20 for the o-ring gaskets. You should also know that when doing Hondas, we almost always use genuine Honda/Acura parts because most of the aftermarket parts out there are inferior in quality.

If you have a good donor 3.2 car in which you can swap parts temporarily, then swap the coils and MAF. You said you got an Acura coil from the dealership, but are the replacement coils in the rough running 3.2 original Volvo or a good aftermarket brand? Also, that 3.2 has over 180k miles with maintenance unknown so yes, very (very very...) common cheaper wear parts that go bad should be changed to new ones to ensure they are not culprits or contributors to the running issue (FPS & fuel filter).

Next, double check your work, which is really saying double check the parts from your work. Say there is a fuel pressure issue with incomplete burn, are your plugs gunked up now? Have you double and triple checked the intake for leaks and ensuring the variable intake runners flap is active? What if the used car dealer replaced some parts with inferior parts or did a cheapo fix on something to get the car running for sale; this should be double checked.

The 3.2 has variable valve timing, cam switching (like VTEC), and variable length intake runners. These all can contribute to inefficiency cat codes. Then there is a history of coils going bad on this 3.2, you say the MAF is dirty, and maintenance is unknown to non-existent. Misfires can move because the engine is split into cylinder banks (1-3 & 4-6). Are the floating misfires along the same bank of cylinders? I am not sure if this engine can do this, but modern engines can retard timing per cylinder, so if there was a misfire one time, it could disappear due to the computer adapting and retarding the ignition timing for that specific cylinder, but the overall issue causing misfires is still there - that's why you might see a different cylinder misfire at different times. It could still be a cat is inefficient, but could some build-up be blown out once the engine is running well? It could still be a fuel pump issue, but if you change the fuel pump, with over 180k miles the fuel filter and fuel pressure sensor should be changed too.

The Approach
So the approach is, swap good parts with the donor where you can (free). Change the cheap known wear parts that could cause problems (cheap, but you have to wait). Double check spark plug condition and read the plugs for each cylinder (free). This will give you much more information and a baseline to work with. Add some good premium gas too because if these XC90s with trouble codes all get their gas from the same gas station, then that could be a source for some of the issues (cheap).

Last thought, if the shop agreed to pay for the tow there, what if you don't want them to do the work. Who pays for the tow back to the house?

[GreenMagicMan]

red pill blue pill - that's the choice we all have to make lol.
Yeah lots of cars with issues and confusing.
Yes, I agree, I do my homework on my little baby coupe and often I buy OEM genuine and / or use the best fluid for critical things - things the robots at the internets tell me to do haha. (like PS fluid, case of ATF fluid genuine Honda... but I use Denso Iridium unicorns on that too as it's a rare CA emissions Honda...) And I pull parts from junkyard like original Nissin calipers when I could not rebuild one.

The owner has AAA so tow back is feasible. We are thinking the shop may agree to fix some of the issues for parts cost (no labor), they did that before for something and were good about it.
I haven't thankfully had to tangle with VTEC issues ever. To date that's a bit out of my wheelhouse. I understand how it works but never got my fingers dirty in their system.
Coils are unknown, but speculating they are good brand like Volvo branded or Bosch.
Some good news: distant family member finally got back to us today and we are thinking we could be able to have a working VIDA software kit sent up.

[GreenMagicMan]

Just swapped in the PEM - no change. Running like s*&t. Under any load almost no power. Light throttle flat roads it runs with charm and ease.
FYI - the 2007 and newer PEM module is located UNDER THE MIDDLE ROW PASSENGER SIDE SEAT!!!!!!!!!!
couldn't find this damn info anywhere. It's not behind the rear passenger wheel well plastic like perhaps 2003-2005 models (?).
And to get to it, you need to slide just the two front plastic clips off of the middle row passenger side front, and unbolt the 1/2" or whatever it was bolts there and the two bolts behind the seat. Then lift the whole seat out. Peel back the carpet from the outside side which reveals the PEM.
It's amusing that the PEM has four bolt in spots - none of which are used. It's held in with an 'in the style of Velcro' crap or poor man's version of Velcro. FFS Volvo.

[abscate]

Leave the cats alone For now, plugged cats very rare and usually only suggested when a shop doesn’t want to work on your car.

Noises in the shaft are cheap to fix once you find the powertrain repair shop; you have a ton of them in VT because of farm tools. At a Volvo dealer, OEM driveshaft replacement will bankrupt you..

With a high mileage Volvo, oil changes of 5000-7500 miles with quality oils is essential. If you don’t want to do this bail out now and move to a more disposable brand car.

[GreenMagicMan]

Just pulled the passenger side upstream O2 sensor - the one right ahead of the cat to see if the exhaust flow was restricted maybe this would help the exhaust exit.
Just made everything louder, no more power at all going up hill.

[pgill]

GMM,

You will need to decide if you want to spend the $$$$ to get your XC90 back to a useful state.

ABSCATE is right, the XC90 is a complex machine, if spending $2,000 to get it running well is out of the question then my best advice is to sell.



Did you swap the fuel pressure sensors between your XC90's? Or did you buy a new sensor?

Does your code reader read PIDs?

If yes then what is the fuel trim? LTFT (Long Term Fuel Trim)? STFT (Short Term Fuel Trim)?

Can you see the throttle opening % on you code reader?

If yes then does it show almost closed at idle?

Does it show 100% or something close when you put your foot to the floor?


Try this test

With the transmission in Park or Neutral

Engine at idle

Press the gas pedal to 15% or 20%

How long does it take to get to 3000 RPMs (use the stop watch on your phone)

Repeat the test on your other 3.2 are the times about the same or very different?


Good luck

Paul

[GreenMagicMan]

Cannot find the fuel pump RELAY fuse. I guess it's internally located in the PEM???!?!?!?

four separate fuse boxes on this car. nice. wtf. my favorite is the f-ing torx 25 under the dash. awesome. sign me up.

Trying my best to DRAIN FUEL out of the fuel rail... to swap in a new or working fuel rail pressure sensor.
'Other' Volvos list to remove fuse #74 for fuel pump relay that 'works for the XC90 "also"'. It does not.

So can I just pull the under hood #8 fuse for the fuel pump?
Started car and it died instantly with the fuse #8 for pump removed.
Now I'm trying to figure out if this car has an ignition kill if pump not working and THEREFORE I still have tons of pressure in the rail.
Since it ran for no more than 1 second I cannot possibly see how the fuel pressure was released at the rail.

You know, I'm trying not to have a fire hose of fuel spray everywhere and all over me when I pull the rail pressure sensor. Should be simple, and it's not.

[chitownV]

When looking at the engine IIRC, on the passenger side of the fuel rail end should have a plastic cover (I think Phillips screw head?) then a schrader valve in which you can push it in to release the pressure while holding a rag over it. This should relieve the pressure. Then have another rag ready when removing the fuel pressure sensor on the driver's side for spillage because there will still be fuel in the rail that dribbles out.

Good Luck.

[pgill]

GMM,

Doe your code reader read PID?

If it does then check the fuel pressure with the code reader

That will tell you if you relieved the pressure.

If you removed the fuse on a cold vehicle that sat over night then running for 1 second makes sense.

If you had recently shut off the engine then the residual pressure should run longer than that.


Note: with the pump not running the fuel pressure will drop very fast with the engine running

Good luck

Paul

[GreenMagicMan]

Paul - Thanks again!! I think it does / may read PID, it's a horrible freight $40 on sale tool. It does show data / conditions "freeze frame" when MIL / CEL code was thrown...

I only read your response after I did this all and posted this below:

Well, whatevs. If anyone reads thru this all...
I kept the fuel pump #8 underhood fuse out.
I also went to passenger rear wheel area and just ahead of wheel and next to fuel tank is the fuel filter.
FCPeuro site showed a schrader valve there to release pressure (for changing fuel filter) so I went ahead and let out some fuel there.
Then I finally got that idiotic T25 bolt out - using a T25 standard size screwdriver 1/4" bit and a small crescent wrench.
Sensor was in very tight. Took some good force to pull it and I had a bread bag around the area and collected the spilling fuel (maybe 2-3 soda cap 2 liter bottles at most, maybe 1-2). It didn't spray out really so that part at least was mellow.
New part is getting picked up now and will post up if it works.
I could potentially replace the fuel filter in case that's plugged.
Re-installed passenger side Oxygen sensor last night and will test drive car in about hour with new rail pressure sensor in.