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

[5cilinder]

Its not a boost problem , its an (potential) airleak problem that can be optimized to prevent worse
Its a small effort with the right tools 10 minutes at most,
Most people also dont resistance measure their glowplugs before winter , because they dont know better
But hey most people spend more time polishing their alloy rimms and that i never do ;-)

[colinbos]

Originally Posted by colinbos

Its got to be high on the last of probabilities. It could also be the condenser or pipes going to and from,

CONDENSOR - I meant intercooler. Sorry if this threw you, Scribe.

[scribe0101]

Pretty sure I've found the problem (until I find another).

Pulled the engine under tray and found it plastered with an oily gunk around the centre.... and this sorry looking resonator box:





I assure you there's an orange seal to the left side of that jubilee clip. Inspecting the top op the resonator box behind the engine, it seems dry and clean, but following the plastic pipe from the box and up behind the radiator fans and it joins to a rubber hose just below the dipstick and there is a small amount of gunk there also.

So I've found one thing to fix but I have a further question:

Is finding oil there normal when the seal fails, or is this highlighting a bigger problem?

If that's a stupid question then I apologise, I'm learning

Regards

Chris

[cheshired5]

Originally Posted by scribe0101

Is finding oil there normal when the seal fails, or is this highlighting a bigger problem?

As long as you're suffering no significant oil loss between services (ideally less than half a litre if any at all) there's unlikely to be a further issue.

Going back to the title of this thread, do you now see how a MAF sensor code doesn't always mean a MAF sensor fault?
In fact it rarely means a faulty sensor.

[sv70]

scribe0101,i had similar problems with the resonator box seals and when i took them off i found that the plastic where the seals fit cracked and in poor shape so i got the silicone hose which replaces the resonator box and makes it a simple connection instead of the fiddly and original flimsy seals.They are £39 but i think long term a better job,got mine off the bay called dph sport in Derbyshire,there are 2 different hoses though so be sure if you order one.

[colinbos]

Nice one Scribe,

The forum strikes (helps) again.

Seals are cheaper, hose is a matter of choice (I went with it) and got mine here. Fits well. Get 4 jubilee clips two on each end as a good back up. Nice tight fit. And a more resolute solution in my opinion.

http://www.partsforvolvosonline.com/...6b41d1bbc50d85



Whats the EGR like ? I reckon that will be bunged up.

[scribe0101]

Okey dokey.

Update is as follows. Changed the seals on the resonator box (only £3.49 each! from Volvo), the air charge pipe and the hose that connects to it in front of the dipstick. Not a hard job, just tricky getting everything seated correctly, and feeding the rigid charge air pipe under and up in front of the engine was the definition of a PITA. It did need doing as was evident by the crap and mess blowing out and there is a minor improvement, but unfortunately that wasn't the main cause and the big leak is still there.

The bottom of the resonator box was the way it was because some genius (<- sarcasm) had been there before and decided to hold the jubilee clamp in place with a self tapping screw that pierced the seal (you can see it on it image I posted on the opposite side to the clamp screw).

My problem now is I don't know my way around this engine well enough to trace the problem, plus it's made harder by the leak only hissing under load when driving. There is a small black hose that comes over the top of the engine and terminates behind the dipstick and that is one further culprit, but I can't be sure.

The car will have to go into the garage now as I need the car for work and can't afford to wait from weekend to weekend to learn and sort this out I have the loan of my cousins car for another week and then I'm stuck, so it has to go in. Gutted to have to admit defeat.

And I didn't get to the EGR valve either. I undid all the clamps holding the black plastic pipe that is fed from the top of the engine and I couldn't budge it at all. I could be wrong, but it seems to me that the only way to get it out without cutting the hose that connects things is to take apart the plastic assembly on top of the engine. From videos I've seen it's the left hand side of the valve and the connecting pipe that collects the buildup, so didn't even bother going in from the other side which is actually easy to access with the air box off.

Anyway, defeated, gutted and will now have to pay labour to get it fixed. Oh well, back to restoring my TR7. Now that's a much easier car to work on

[scribe0101]

Arrrggghh!

As soon as I pressed submit on the above post I realised I should have taped tissue paper around all the suspect hose connectors and took it out for a drive. The evidence of the hiss would be visible by the tissue paper that was either grubby or blown apart.

Like I said earlier, I'm still learning about this engine. Shame I'm out of time. If I could afford to wait another week I may have ended up victorious.

Oh well.

[colinbos]

A valiant effort Scribe.

I know may way around a car, but the XC90, it seems to be a different animal all together, and one with a bite too.

The further into ownership I get, I become more used to it and know they take some time, diagnosis and this forums help to fettle.

Shame time has caught up, I think you'd have won this one with more.

[5cilinder]

Why not methodicly checking every part in the induction system? starting with the intercooler, hoses and piping

Pressurize it with a can ,clamp and bicycle pump . its better than guessing