XC90 2.5T 2006 misfiring problem

[vegasjetskier]

I wouldn't buy new coils yet, as the odds are about 1 billion to 1 against four or five of them failing at the same time. I think the problem is much more likely to be the MAF sensor. I'll see if I can find some diagrams showing where it is.

[vegasjetskier]

The MAF (Mass Air Flow) sensor measures the amount of air going into the engine so that the Engine Control Unit can supply the correct amount of fuel through the fuel injectors.

I don't have a diagram for the 2006 model year, but I do for 2005. Maybe it's the same. Item #13 is the MAF sensor.

Here is a thread discussing how to clean it. It's for a different car model, but probably applies to yours too: https://www.matthewsvolvosite.com/forums ... php?t=5168

You wrote that you cleaned the air filter. Do you have a K&N or similar type filter? If not, you're not supposed to clean it, you just throw it away and put in a new one. That may be your problem.

[JDS60R]

I agree.

On this new a car to have all of the plugs, injectors or coils go is silly. After 15K some cars need plugs.

The MAF mass air flow sensor does control the fuel usage as does the first oxygen sensor. The MAF is weaker than the O2 sensor so I would start with the MAF. Clean it once the car has cooled with a proper MAF cleaner.

It is possible you have a bad MAF and that cleaning will not resolve the issue. A relacement may be needed.

Its ok to use K&N. Better not to clean them. They filter better when dirty and still have more flow than is needed. Some cars do have an extremely tight calibration on them. Please put a stock filter in after cleaning the MAF as this has fixed the concern you are having previously.

[Dhimas Yuniarso]

Did replaced the plugs and the light back on after 3 km driving. (this time without any sign of misfiring)

Back to garage this morning to get the error code

1. ECM-2900 Fuel Pressure control valve/fuel pressure. Faulty signal too high/low
2. ECM-290D Fuel Pressure signal too Low.
3. ECM-120D Intake air temprature (IAT) sensor Mass air flow. Faulty signal/signal too low.

I think you guys are right, this is related to MAF problem, or is there anything else to check?

Thanks

[vegasjetskier]

What type of air cleaner do you have?

There is an IAT sensor also. I'll see if I can find a diagram showing where it is.

[vegasjetskier]

I turns out the IAT is integrated into the MAF. Here's a quick tutorial on how to clean up the MAF connector and hopefully solve that problem: http://volvospeed.com/Repair/maf_secure.php

[Dhimas Yuniarso]

Thanks Vegajetskier.

I am still in garage now, when I ask them to open the MAF sensor, they found out the airbox was loosen so that the box was moving (not in proper position).

They removed the MAF sensor and get it cleaned and also taighten the air box.
I think this is related to the last link you send to me, a bad connection due to vibration. If the airbox was loosen then i can imagine the connection failure and this is not only vibration but moving airbox(worst).

Now the machanic is doing some test drive and let see if they can get the problem fix.

I will report the progress.

[Dhimas Yuniarso]

Mechanic back from testing and the ceck engine light back on after about 10km drive test. No sign of misfiring. Same error code.

Any other clue gentleman?

Thanks

[Dhimas Yuniarso]

I did replaced the air filter with new original/stock.

[vegasjetskier]

Mechanic back from testing and the ceck engine light back on after about 10km drive test. No sign of misfiring. Same error code.

Any other clue gentleman?

Thanks

Which codes are you still getting?