D5 (2005 on) Maybe it is the MAF sensor after all?

[scribe0101]

Hi All,

Starting to change my mind a bit now. Here's a rundown of my car's symptoms (2010 D5 XC90).

• The 'Engine System Service Required' message came up several weeks ago.
• Got hold of VIDA DICE which pointed me at a MAF issue.
• Searched posts on here for similar problems and the majority of the discussions seemed to redirect people to the swirl valve.
• Checked it out and sure enough the control arm wasn't connected.
• Connected it back up and the message went away
• A week later the message came back and I found the arm had come off again.
• This time the arm wouldn't stay on and the message persisted.

At this point I was pretty sure the swirl control arm was the problem. I've seen posts here about fitting limit brackets, but at £6.99 I just bought a new arm and fitted it.

I've been driving around hoping that the message would clear but that hasn't happened. Tonight more problems have shown themselves:

• The car has basically lost most of its power (has at most 1/2 the power of my wife's 1.3 Suzuki Ignis)
• When I try to accelerate its like the car is struggling through treacle
• If I put my foot down all that happens is it kicks down a gear or two and revs high, but doesn't have much pull at all.
• I've checked the swirl arm and it's still attached

It's dark at the moment so I'll put it on VIDA tomorrow to see if anything else has arisen, but I'm starting to think the disconnected arm was a red herring (seen people on here driving thousands of miles with it off without issue). If VIDA shows nothing I may change the MAF sensor.

Is the MAF a regular fail (I can't seem to see a post on here where someone has had to change it)?

Or is anyone aware of any other issues hiding under a MAF problem?

I've heard overfilling oil can cause problems, but it's been about 8000 miles since the last service and the level looks fine to me.

Cheers

Chris

[colinbos]

A common problem that occurs when you get a MAF fault code is an air leak, split pipe in the induction system. Also, check your EGR valve and pipe work. It could be clogged with carbon reducing the air passing thru. There are many posts on how to clean this out (dirty work)

MAFs do fail but not often and are not a common problem. Check youtube for MAF testing before you spend out to replace.

Check all pipes and in particular the resonator pipe seals for air leaks. They can leak and cause limp mode to be effected giving the symptoms you describe. Ive experienced this.

[scribe0101]

Many thanks.

I'll check the pipes and EGR valve and maybe buy some MAF cleaner - as soon as I stated I couldn't find anyone with MAF problems I found this post http://www.volvoforums.org.uk/showthread.php?t=178304

Is what I described about the loss of power officially 'limp mode' (when I've seen other cars go into limp mode there is an associated message or warning light)?

Cheers

Chris

[cheshired5]

You have Vida so you have no excuse to not test the MAF.

[colinbos]

Originally Posted by scribe0101

Many thanks.

I'll check the pipes and EGR valve and maybe buy some MAF cleaner - as soon as I stated I couldn't find anyone with MAF problems I found this post http://www.volvoforums.org.uk/showthread.php?t=178304

Is what I described about the loss of power officially 'limp mode' (when I've seen other cars go into limp mode there is an associated message or warning light)?

Cheers

Chris

As Cheshired5 says, the MAF can be checked as working via VIDA. Don't go buying MAF cleaner until you've done this.

Yes, limp mode is the engine in reduced performance, self instigated, No warning are given or displayed save for the Engine System Service Required message.


Also search for Posts including Resonator seals. Check them, they are prime for popping and leaking.

Any other noises from the engine ?

What mileage is on yours ?

[scribe0101]

Thanks guys,

Mileage is about 97k and no other noises that I can identify (but these aren't exactly quiet engines )

I haven't had much time to learn how to use VIDA other than identifying the MAF code (which right now I don't recall).

When you say test the MAF with VIDA, I'm assuming that as it's already raised a code to do with the MAF there's a specific test that can be run through the software?

If so I'll have a look for that.

Thanks again

Chris

[colinbos]

My moneys on the EGR valve being clogged and or an Air leak.

You can see if the MAF is working within VIDA. The MAF parameters can be viewed live and increasing and decreasing wth engine input.

There are a set of parameters that it should work within. I haven't done this test myself. Someone else may explain this more eloquently than me !

Have a play, you'll find it.

[5cilinder]

Like others said, its more probable that you have an airleak than a maf problem.
Major suspects are intercooler, resonator seals(cheap) or if you took a few speedbumps to have a split pipe underneath the oilsump.
Its easy to device a simple airtight test in various parts in the induction system with some cans in airhoses and a lid with hard niple to connect a bicycle pump to pressurize the system part and listen for leaks.
Small individual airleaks will be known that otherwise wont be noticed by the tolerance in MAF /lamda mismatch, So its not work for nothing , airleaks tax the turbo and wear it down due to somewhat overspeeding.
If thats all ok check also the intake between the turbo and maf if there is leaking hose or loose clamp the maf reading will also be messed up.
If thats all ok then (after callibrating the maf in vida didnt help ), its probably the maf

[scribe0101]

But of an update:

I haven't had time to put it on VIDA yet, but was forced to go out in it for a short while at lunch.

Drove with the window down (didn't do that last night when the problem occurred as it was below freezing), and even under mild acceleration there is a very loud hissing noise, kinda like that little spirt of air when you change air tools, but prolonged under acceleration.

When keeping a constant speed the hiss is not there, but (for example) even a small increase on the accelerator to maintain the speed up a hill results in this.

It's going to have to wait until tomorrow before I can get it on VIDA and give things a good inspection, but if I'm not mistaken this hiss should direct me to the seals on the resonator box (as suggested by colinbos)?

I'll check over as much as I'm able though, and I'm probably going to give the EGR a clean out anyway and any other places I can easily get at after seeing this video: D5 Euro 4 EGR Clean Video. Quite shocking the amount of build up in there.

I'll hopefully post the results of my investigation tomorrow.

Cheers

Chris

[colinbos]

Originally Posted by scribe0101

But of an update:

I

It's going to have to wait until tomorrow before I can get it on VIDA and give things a good inspection, but if I'm not mistaken this hiss should direct me to the seals on the resonator box (as suggested by colinbos)?

I

Its got to be high on the last of probabilities. It could also be the condenser or pipes going to and from, but in any case, you definitely know you have an air leak.

The resonator seals are from Volvo (less than £10 for 2 I think, or fit a silicone resonator pipe as mentioned in other posts. Ive got one on with two jubilee clips on each end, so no matter how much pressure goes thru, its staying put and less likely to crack or split.

If its not that, you have a bit of digging to do, as well as possibly in your EGR !