Mass Air flow Sensor XC90

[mev]

Hi there,
I have a 2008 XC90 185bhp 2.4 D5 diesel.
While accelerating when the engine is warming up there is a loss of power for a second or two and the "engine system service required" masseage is displayed. This can happen several times during warm up.
I plugged in and the code for this is ECM-135F Mass Air Flow (MAF) Sensor.
I have removed the MAF sensor and visually it looks fine, electrical connections are good and I did not find any leaks in the pipe work. I have changed the air filter.
The measurements from the MAF sensor are 50kg/h at 700rpm, 60kg/h at 1025rpm, 90kg/h at 1500rpm and 130kg/h at 2000rpm.
It seems to be pointing to a new MAF sensor but before I get one I wanted to run it by you guys as a new MAF sensor from my Volvo dealer is a whooping €505.
My questions are:
1. Can I drive with the MAF sensor disconnected without damaging the engine and only expect to have lower mpg.
2. Can I clean the MAF sensor with a MAF sensor cleaning spray as from reading other threads some people are for it and some are against.
3. Could there be other things that I need to check before getting a new MAF sensor.
4. Could it be some other problem entirely and I am heading in the wrong direction with the MAF sensor.

All comments are appreciated.

[gmonag]

Check your swirl arm. Malfunction of the swirl valve can cause the diagnostic trouble code to be generated.

[cheshired5]

Originally Posted by mev

Hi there,
I have a 2008 XC90 185bhp 2.4 D5 diesel.
While accelerating when the engine is warming up there is a loss of power for a second or two and the "engine system service required" masseage is displayed. This can happen several times during warm up.
I plugged in and the code for this is ECM-135F Mass Air Flow (MAF) Sensor.
I have removed the MAF sensor and visually it looks fine, electrical connections are good and I did not find any leaks in the pipe work. I have changed the air filter.
The measurements from the MAF sensor are 50kg/h at 700rpm, 60kg/h at 1025rpm, 90kg/h at 1500rpm and 130kg/h at 2000rpm.
It seems to be pointing to a new MAF sensor but before I get one I wanted to run it by you guys as a new MAF sensor from my Volvo dealer is a whooping €505.
My questions are:
1. Can I drive with the MAF sensor disconnected without damaging the engine and only expect to have lower mpg.
2. Can I clean the MAF sensor with a MAF sensor cleaning spray as from reading other threads some people are for it and some are against.
3. Could there be other things that I need to check before getting a new MAF sensor.
4. Could it be some other problem entirely and I am heading in the wrong direction with the MAF sensor.

All comments are appreciated.

The answer to your questions is 4.

You have diagnostics so follow the associated troubleshooting and fix path.

[mev]

Hi,
I checked the swirl flap link and it was in place. I disconnected it from the swirl flap rail and found that there was a lot of latteral movement on the swirl flap rail which makes me think that the swirl flap rail is worn/broken. There was also some oil around the area.
I drove with the swirl flap link disconnected and this made no difference, I still get the loss of power on acceleration and the "Mass Air Flow Sensor" fault code.
I am now thinking that I need to replace my swirl flap rail.

[gmonag]

See this, it might help you decide.

http://www.volvoforums.org.uk/showpo...95&postcount=8

[osullivant]

If you do indeed need to change the maf I bought a brand new Bosch one from Amazon.de for just €157 euros delivered,

BOSCH 0281006184 Luftmassenmesser

But in reality I think it was not needed, at that time I had indications that the tmap was gone the maf the EGT sensor, the Turbo was not calibrated, and various other suggestions, all of which I tried but to no avail, eventually I replaced the turbo actuator which hugely improved things and then took the DPF off and had it cleaned out, I fitted a new dpf temp sensor and since then car is back doing close to 40mpg and driving in a desirable fashion, looking forward to the first real test on Thursday 100 mile run on motorway.

Am tempted to sell it now and move on but it is so nice to drive when it is going properly....

[osullivant]

Is that Tulla Co Clare.

I am in Cork, you are welcome to come and try if mine fixes your problem...

I have VIDA and Dice

[mev]

Hi T.
Yes it is tulla Co. Clare.
Thanks for the kind offer but I will give it a skip at the minute as I am now focusing on replacing the swirl throttle valve rail especially after watching the swirl throttle video that gmonag put up a link to.

[gmonag]

Make sure you do a proper diagnosis before you start changing parts otherwise it can get expensive and time consuming. Don't swap parts on the off-chance.

[osullivant]

Originally Posted by mev

Hi T.
Yes it is tulla Co. Clare.
Thanks for the kind offer but I will give it a skip at the minute as I am now focusing on replacing the swirl throttle valve rail especially after watching the swirl throttle video that gmonag put up a link to.

do not do it, you need to remove the injectors, pipes etc etc, you will end up needing to fit new injector seals, possibly helicoil the injector bolts etc and you might still have an oil leak in the manifold.

try the Maf first. My butterfly valves were perfect yet seemed to be disconnected, when I took the manifold off for the second time on the advice of the volvo dealer that this may be the issue....

A wise man learns from his own mistakes, a very wise man learns from the mistakes of others.

with VIDA it is possible to see if the swirl valves are actually operating, ie if they are still connected to the rod.



Tony.