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

[GreenMagicMan]

This car was taken to a back country independent mechanic Volvo specialist.

- Fuel pump: He said the pressure was ''too high" and wouldn't come down on climbing a hill and giving it heavier throttle...
- Prop shaft: He said he heard it banging around (I did too big time driving it back from shop), that it needs clutch pack, and a few other things probably... he also said we could disconnect the rear AWD driveline and drive the car as FWD.
-"2 or 3" cats. I only thought these cars had two converters so IDK what this is all about. Said at least 2 were clogged and maybe 3rd didn't check that one.
He said that is contributing to the car's stumbling and misfires.

If the fuel pump really is the bad part, starving cylinders for fuel (or air or spark) will cause misfires.

We already installed 6 Denso TT twin tip iriidum spark plugs as recommended here on our other XC90... That worked really well on the other car.
This one had #6 cylinder ignition coil wiring fried and destroyed, and the coil was shot so that was all replaced. The old (original??) spark plug in that cylinder looked bad. Car had (5) Bosch plugs and one cheaper Autolite plug in cylinder #1 (nice) before replacing them all with Denso.

We are in the state of Vermont. At 15 years they do not require emissions anymore so CEL can be on and no one cares. That's 1.5 years from now. Inspection is due in March 2021. We could drive it until then, flunk an inspection and then have 90 days to correct it, then eek by 6 months until it's not required. I am sure this strategy will get flamed but these people I'm helping (my girlfriend's family) has 3 Volvo for safety reasons for crash protection and they don't have lots of cash to throw at these cars (Mechanic said at least $4000 - $5000 to repair what he found so far in 2 hours of labor).

I can 100% do the fuel pump if that's really the issue. I assume, yes, if it is broke it will cause the 4 cylinders misfires as stored in the ECU. I have basic scanner and can keep on top of MIL CEL codes and re-set as needed for testing.
I can do cats but I will not bother buying $5000 - $6000 in Volvo official converter parts (that's nuts on a 2007 car with high mileage - c'mon it's totaled if so).

We may in fact sell off this car for parts and leave it for dead or Viking Funeral it (that's what I'd like to do).
I buy and sell cars as an interest of mine and help close circle, and I always list every fault on the car - er, to a fault lol. So all this would be clearly spelled out.

Girlfriend's sister loves her car and was crying when she heard the bad news. Visually looks great but it's got internal problems...

I could go to massive junkyard and pull most of these parts (not cats). I could work on the rear AWD driveline repair late summer and fall before winter. We will NOT be having the mechanic fixing the car for $4000+ so unsure what to do.

[GreenMagicMan]

Re: FUEL PUMP.

Car always starts right up and goes on low idle quickly. Performs just like the other V6 and V8 XC90 we have.
It never stalls or stops.
Symptoms: going up big hills or getting on throttle more than 1/5 to 1/4 throttle for example it may stumble and shudder a little bit. This car (like our other V6) has thrown 4 separate misfire codes.

This is why I am questioning if it really is fuel pump. Could it instead be the fuel pressure regulator?

[wanderdüne]

First things first; do yourself a favor and either download a VIDA image and purchase a cloned DiCE on ebay or wherever or get something like a icarsoft i906 to read the car and use the VIDA download as a reference. With the VIDA/DiCE combo, you can test the fuel pump. Using a OBDII reader is worthless for these cars. You'd be out a maximum of $150 for either option and save yourself some massive headaches along the way. Helps us out here, too.

You can get a prop shaft here for reasonable money: https://coloradodriveshaft.com/products.htm

[pgill]

GreenMagicMan,

I am going to take credit for the Iridium TT plugs.

I own two 3.2s and if I were you I would do the following

1. Denso Iridium TT sparkplugs --- Done

2. Fuel Rail pressure sending unit (replace it) - The computer controls the pressure by turning the pump on and off based on this sensor

3. Disconnect the MAF and test drive (Does it drive better with the MAF disconnected, if yes replace or clean the MAF)

4. Thermostat is likely broken - replace it

Good luck

Paul

[oragex]

This car was taken to a back country independent mechanic Volvo specialist.

- Fuel pump: He said the pressure was ''too high" and wouldn't come down on climbing a hill and giving it heavier throttle...
- Prop shaft: He said he heard it banging around (I did too big time driving it back from shop), that it needs clutch pack, and a few other things probably... he also said we could disconnect the rear AWD driveline and drive the car as FWD.
-"2 or 3" cats. I only thought these cars had two converters so IDK what this is all about. Said at least 2 were clogged and maybe 3rd didn't check that one.

I'm not sure how Volvo specialist is that place, but I stopped reading after "the pump is bad because the fuel pressure is too high". Either that place has never seen a Volvo, either it's a total scam artist. And reading about the clogged catalytic converters, while it may happen, it's also a classic garage scam. If your fuel pressure is indeed too high, that is a typical faulty PEM (google up) problem, a classic, that's why I'm saying harsh things about that garage. $50 used from Ebay. Which engine is this ? Bosch usually makes the genuine ignition coils for Volvo. You could check for a misfire yourself by disconnecting the injectors one by one (it's easier than disconnecting the plugs) - see video. The 3.2 may also have an issue with the MAF that may cause stuttering, misfire codes and loss of power. Also making sure all ignition coils work properly, before starting to replace fuel pump, AWD and other things. If the engine is 3.2, worth replacing the thermostat if never done. Ask us which are the quality brands, we like to buy online from sites likes Fcpeuro.com but need to know the right brands for the engine. I have quite serious doubts about that garage and if I'm right, pretty much all repairs he suggested are not needed

Also see this topic on the 3.2, the person fixed the problem with a new MAF viewtopic.php?f=10&t=87918

[GreenMagicMan]

Credit dully deserved Pgill!!!! Thank you again!! Saved one car's bacon.

Not sure the Tsat is broken. Basing this on the silver '07 that was broken and what it had for symptoms. The car goes to 50% on the gauge briskly just as the silver car we replaced the broken T stat on. More credit to this forum for help with all that!!
That particular T Stat broke a tab on the black plastic so the T Stat was always loose and 'open' (it didn't fail 'open' by seizing up in another words).

Heat works well in the car.

[GreenMagicMan]

Wow! Thanks Oragex. DANG... that's some information there.

I could not quite remember what this mechanic said so was from memory from 3 days ago. I just dug out the report he wrote up and am directly quoting it here now:

" Read codes many codes set checked history. Misfire codes had changed.
Check fuel pressure and duty cycle on computer and check fuel pressure with gauge. Pressure sensor looks like it is in agreement at this time with the sensor at the rail. Duty cycle higher than expected 52% at idle should be low 30s and mid 40s normally start posting codes.
Road test car and found duty cycle does jump when on the road.
Drove up the hill and asked a lot heavy throttle to see if fuel pressure would drop lower than needed and cause skip. But car did not have a dead miss but would not wake up and perform.
The more I asked of it the less it performed.

I had a car like this in the past and it was melted cats.
With the history of codes and misfires I feel like this is what is wrong and they will need to be replaced at next inspection.

Prop shaft was vibrating, felt like center bear(ing) or support is shot and some strut noise.

Fuel pump will need to be ordered about $750 installed.

3 aftermarket cats installed with gaskets, if no exhaust manifold bolts break, about $2700 and another estimated $300 if they do.

Used prop shop installed $450
Struts are about $300 each installed.
Contact customer to explain what I had found, not sure if the car is worth fixing."

[pgill]

No worries.... I am always glad to share what I've learned

Note: what Oragex wrote is an important consideration not to over look.

The 3.2 doesn't have a traditional Mechanical regulator, it is a return less system that adjusts the fuel pump speed to maintain pressure.

Here is my understanding of how it works

1. Fuel rail sending unit measures the pressure and it sends a voltage signal to ECU that matches the pressure

2. ECU uses this information to communicate to the PEM

3. The PEM controls the fuel pump using PWM (or duty cycle if that makes more sense)

4. This feedback loop is constantly updating as you are driving down the road

If I remember correctly early Volvo's with the 3.2 had the PEM mounted in the wheel well behind the liner and for later vehicles the PEM was moved to inside the vehicle.

As OrageX pointed out you may have a PEM problem.

For my 3.2s the PEM is mounted inside the vehicle so I haven't had the corrosion related problem of the earlier cars.


One last thing my S80 3.2 does have 4 CATs

But I agree with OrageX the diagnosis from the garage that you went to seems to be making a lot of assumptions without completing the diagnosis.

It may be time for a second opinion.

Good Luck

Paul

[GreenMagicMan]

Thank you again, I'm going to look heavily into the PEM and MAF for good measure as well.
I also have a cringe inducing CEL list from the 2005 V8 XC today on my scanner (face to palm).
Naturally, many things I've never seen triggered and I've never dealt with so either steep learning curve on that one for me or we may have to consider replacing that car too

[pgill]

It could be the PEM but it also can be a sticking pressure sending unit.

The PEM is counting on good pressure reading from the sending unit

For the MAF you can switch between your 3.2s (I think you wrote that you have two 3.2s)

Let us know what you find out

The XC90 3.2 is a very reliable vehicle

But it can be a bit demanding at times.