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

[chitownV]

Okay, good info which changes how you will approach this. It will take some new parts since you are basically catching up to the assumed non-maintenance of the vehicle and some snake oil. So they had it for a year, how did it drive right after they bought it?

Do the fuel pressure sensor first. See if it improves. Also, get a fuel filter and change that out. Easy 10-15 mins. Then run premium gas to see if there are still issues with misfiring.

I personally like to use original Volvo spark plugs because on an issue like yours, it helps eliminate any variability from the spark plugs. If one coil was changed then the others are not far behind. Changing all 6 ensures there isn't a load problem with the coils.

Next, are the cats. Let's assume there might be an issue with efficiency, not necessarily completely gone. Even if the fuel system corrects the running issue, assuming the engine ran rich, there might be some build-up in the cats. So, run a small tank of Cataclean or similar (you can find on Amazon for ~$25 and read the instructions) and premium gas to try to blow out any build-up that there might be in the cats. Then after, change all O2 sensors. Even if you gut the cats, the primary O2 sensors are needed.

2007 transmissions had issues and assuming the valve body was changed, it needs some maintenance. Do a fluid change with specific JWS 3309/T-IV (like Mobil 3309 you can find on Amazon or Toyota T-IV). Not sure if it is related to your specific 3.2, but transmission could also affect the power to the ground.

FYI, A bad driveshaft CV and/or a center bearing can also lead to bad driveshaft joints. So, if there were many miles with the vibration and knocking, it wouldn't be a surprise if the entire driveshaft will need to be replaced.

Do a once over on the engine visually and by hearing. Ensure there aren't any intake leaks from the air filter box to the manifold.

The DICE is a simple adapter for the OBDII to USB. I run my VIDA on a virtual desktop.

So, now do a spreadsheet or write down how much time and money it will cost just to get through these issues and see if it is worth it to fix. For a safe vehicle, I understand getting the Volvo. However, there might be other XC90s with less problems, but they might still need maintenance since it appears the budget only allows for a higher mileage vehicle.

Hope that helps your situation.

[GreenMagicMan]

Great info ChitownV thanks!
I replaced the 6 spark plugs with Denso Twin Tip iridiums. It helped when the car was running very poorly.
In a few min, I'm swapping in a presumed good fuel rail pressure sensor from our silver car to this blue car and will test drive it right away (and report back).

it drove well after they bought it - but it shot two ignition coils about 4-6 months after, threw a cat code, and we did a 3rd coil a month ago. It drive very noticeably much much worse in the past couple weeks.

Mechanic here said we could disconnect the rear AWD driveline and just run it FWD. Could that be doable, even for short term to preserve it?
Also, looks like exhaust needs to be removed to get at that driveline :/

[chitownV]

If you basically have another 3.2 that you can swap some parts off of, after the fuel pressure sensor, also try swapping the 6 coils to see how it runs. I always recommend changing all 6 coils at the same time since if 1 is bad, the others are not far behind. This is a good example of that.

I have not personally removed a driveshaft for 2wd, but I believe a couple others have. I don't believe there should be dash lights as the DSTC uses the ABS sensors. Yes, when you have to remove the driveshaft, you have to remove the exhaust to get the heatshield off. So, order a new gasket where the exhaust meets the downpipe. I would also buy a set of new nuts (x3?) for that downpipe to center resonator connection due to rust.

[GreenMagicMan]

I disconnected the fuel rail pressure sensor tonight. No change, car still runs horribly uphill and huge loss of power.

Was starting swapping in a PEM tonight but got too late. Will try that one tomorrow but not that hopeful.

[chitownV]

With the fuel pressure sensor, it cannot just be disconnected to diagnose. It has to be changed. The part is less than $40 from FCP and if you purchase from somewhere else, go for Bosch. Pgill gave a link to the part earlier in this thread. FCP is in Connecticut so I am assuming you can get the part quickly. I would not suggest swapping the FPS from one 3.2 to the other because you can damage the sealing o-ring. Leave the PEM for now until you change the FPS because there is a risk of ruining any modules upon removal and installing (think static electricity, accidental dropping, etc.).

After the FPS, then swap the 6 coils.

[GreenMagicMan]

Hi - thanks again for your help and input
Didn't realize FCP was in CT and yes, it should be somewhat quick.
I was hoping to zip thru this and get myself away for a 1-3 week getaway about 5 hours from here...
(not going quickly).

I read at the FCP euro site that you could unplug the FPS and if it runs fine - boom - there's your problem. Maybe that's not so (?)
Link here: https://blog.fcpeuro.com/fuel-pump-prob ... sdiagnoses
and the direct quote from that link page here:

"How to Test a Bad Fuel Pump
Disconnect Fuel Pressure Sensor
The easiest diagnoses is to disconnect the fuel pressure sensor and see how the car performs. This will most likely cause a check engine light in the car, but the ECU will assume a worst case scenario and order the fuel pump to run at full pressure. If your car runs better without the sensor, then you’ve just found your problem."

This Blue car has 3 new ignition coils in it, maybe I can get 3 more new ones to join them and the new Denso twin tip iridiums I put in (thanks again Paul for the advice earlier this year!).

[chitownV]

Yeah, what you want to get to is baseline for running. Get a new good FPS so that adaptations can start readjusting and get the fuel filter along with that order. It could still be a fuel pump, but start with good cheaper known wear parts and fresh premium gas. I have seen bad gas affect vehicles. Bad gas could have water and sediment in it.

Swap all 6 coils in case you have a bad 'new' coil. Stick with good brands from FCP and remember they have a lifetime warranty on all their parts. Just so entire ignition system is checked, double check your work. A spark plug could have cracked or some other issue occur (like oil leaking from valve cover gasket into spark plug hole). You might be able to read the plugs for running condition in each cylinder too.

Remember that you are looking to ensure systems are good not just the single part problem. Good luck.

[GreenMagicMan]

I still keep wondering about the "clogged cat" possibility.
The exhaust certainly feels restricted and strangled. After coming up the hill here the cooling fans were ROARING for 5 minutes after shut off (thankfully I can tell Volvo at least has a good to great cooling system). Temp gauge never went over 1/2
But the heat from engine was blasting up the back of passenger side of engine and was near melting medium cut grass the car was parked over. You could smell the grass just about smoking.
Can't get Bosch FPS or coils here this weekend and not sure they would want to buy 6 new coils but I can suggest it anyway.

Mercifully, yesterday after phone call, the used car place they bought it from 1+ years ago agreed to free tow it back to their shop and try to at least give free diagnosis about what's wrong.
I was hoping if there was a fueling issue to at least have sorted it out and maybe have them focus on the AWD driveline / clogged exhaust. Tech there said he has seen some cars with clogged cats although not common.

Considering pulling 1-2 O2 sensors to free up an exhaust outlet or even removing center exhaust or drilling holes. Maybe I'll just wait for the shop to see what's up.
I do think I might pop in that PEM since it's here anyway. I would disconnect the neg batt terminal and I'm an old pro at swapping in and out regulator / rectifiers and travel with spare for those little particular pieces of sh*t. Props if you know what a R/R is. Not too worried about damaging a PEM unit.

Not even 2 months ago this car ran like a champ. Tight steering, good braking and handling and excellent engine power.

[chitownV]

Sometimes hot cats is not from clogged cats. A bank or cylinder can run lean and also run hot. A bank can run rich and send unburnt fuel into the cat where it ignites, getting hot. Remember to diagnose what lead to clogged cats. It would 'suck' to spend money on a cat, or to de-cat it, and then find out it was a simple reachable wear part causing the issue in the first place. Also, when you remove the cat there are other problems, like the exhaust will smell all the time and there could be annoying (not good type) droning raspy sound inside.

You can swap coils from the good 3.2 if that is running well. Remember you are trying to eliminate possibilities while you try to find the real issue. This leg work is how it goes without more specific info from VIDA.

[GreenMagicMan]

Fair points, thanks.
Yeah, we have to get the VIDA tool. Been so frustrating without one and without a FSM.

The thing is, with brand new coil, wiring and Denso TT plug, cylinder 6 is still saying a misfire. And the specific cylinder misfires have not always been the exact same cylinders (after clearing codes).
Misfires have many sources: air, fuel, spark. The silver car was showing spark on all 6 cylinders. New plugs helped but apparently on top of the lousy old worn out plugs (that were some bizarre tri tipped FoMoCo spark plug), there was also a bad / dirty MAF. Could have chased that a long time on the spark side and waited for parts and spent $35 - $70 per coil etc... and maybe not helped it's issue.

I'm still very new to the Volvo world. 95% of my experience now is with the Honda world. 3 cars: Integra 19.5 years still running great I sold off, TSX I had 2 years and had a couple issues (including one fried ignition coil. 6 speed manual and shattered left ankle brought me to my first AT next), and current Accord coupe for 3 years runs like a champ at 181K miles.

When I found the cyl 3 was misfiring on the TSX and and proved the coil was shot I bought a new one at Acura dealer for $120. Part sales guy said he would not buy all 4 new and that their coils (almost) never go bad, and just 'cuz one went don't waste my $500 on all new ones. That was one dealer perspective and different marque and coil maker (likely Denso), I know.
But also had two coils go out on motorcycles and simply replaced the bad one and then drove years and 20,000 miles on sport bike without another issue.
Even with this blue car running horrible - it's not flashing the CEL, and with the other P0190 code there's got to be some sort of fueling issue.