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  #1  
Old 09-11-2019, 02:59 PM
Philm35 Philm35 is offline
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Location: Cincinnati, OH USA
 
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Mein Auto: 2011 BMW 335d
Mass air flow sensor fault-After Carbon Buildup Blasting

Yesterday my 2011 335d with 83k miles lit up the "Engine Malfunction" warning, with the advisory that the engine has "reduced power". The car has been running perfectly, and fuel mileage has been consistent.

Dealership diagnosed a mass airflow sensor fault. They want to replace it for $645.

Two months ago the car had the intake system dismantled for carbon-buildup walnut shell blasting.

Could a sensor failure be somehow related to the carbon buildup, or its repair two months ago?
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2011 BMW 335d, Space Grey/Black, Sport, Premium, Cold Weather, Convenience, Nav, Harman Kardon/Sat, iPod
2010 Audi A4 2.0 Quattro P+ 6MT (Wife's car)
2004 BMW R1150RA
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  #2  
Old 09-11-2019, 10:50 PM
ard ard is offline
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Location: Sierra foothills, California USA
 
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Mein Auto: '12 X5 35d/E39M5/996TTX50
If they did it right, probably not related.
Impossible to prove.

You're not going to pay a dealer to replace, right? $100-150 part (Bosch OEM)..15 minute to pop in. As I recall. Even the BMW branded OE part is only $275-300



Edit. I know people get nervous... "I better let BMW do it, that way I have them standing behind their work". Unfortunately that is generally a suckers bet.
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Alignment here: The Definitive Alignment Thread

OE is Original Equipment aka 'BMW Original Parts' aka 'What you buy at the BMW dealer with a BMW label'

OEM is Original Equipment Manufacturer... EITHER the company that made the OE part or.... A part this is identical to the OE part, but is sold by the OEM under their own label


OEM is not what BMW sells


http://www.bimmerzone.com/category/T...ricks_OEM.html

https://www.turnermotorsport.com/t-OEvsOEM

Last edited by ard; 09-11-2019 at 10:53 PM.
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  #3  
Old 09-12-2019, 05:55 AM
Philm35 Philm35 is offline
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Location: Cincinnati, OH USA
 
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Mein Auto: 2011 BMW 335d
Include in that price is the cost of diagnosing the problem, but I agree it is a rather steep estimate. I intend to discuss it with them today.

This 335d has had far more of its share of intake-related problems than it should.

EGR cooling sensor, two carbon build-up blastings, one replaced fuel injector, and now the MAF sensor. I've lost track of how many thousands I've spent on the intake system of this car.

I love the car... I wanted to keep it for several more years, but now I'm debating whether that's a wise idea.
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2011 BMW 335d, Space Grey/Black, Sport, Premium, Cold Weather, Convenience, Nav, Harman Kardon/Sat, iPod
2010 Audi A4 2.0 Quattro P+ 6MT (Wife's car)
2004 BMW R1150RA
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  #4  
Old 09-12-2019, 06:23 AM
KeithS KeithS is offline
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Location: Central NJ
 
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Mein Auto: '11 335d, '17 340iGT
Mass air sensor failures are somewhat common. I've needed to replace them on more than one BMW. Our D had it replaced at about the same mileage (different fault code - power was not reduced). Was covered under the extended warranty.

Don't know if it's luck or driving pattern but our 335D has actually been the most reliable car we've ever owned. 110K miles and have had: One carbon cleaning, MAF, one NOx sensor, glow plug controller, and DEF tank (usual bad temp sensor). Non engine issues included radio antenna amplifier and the steering rack (blew a seal). I've done very little to the car, original belts, hoses, injectors, and coolant (dealer keeps saying it's fine). But now that my driving pattern is changed to mostly short trips, for the health of the car, it's probably best to let it go to someone who will drive it more than I will. In case anyone is interested (Space Grey - black - premium- cold weather) I'm in NJ.
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Old 09-12-2019, 06:28 AM
Philm35 Philm35 is offline
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Location: Cincinnati, OH USA
 
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Mein Auto: 2011 BMW 335d
I don't drive it like a grandmother, but I don't do track days with it either. I'd say I use it pretty normally, with a good mixture of highway miles and city driving.

I also had the DEF tank issue, and a couple of incidents with clogged DEF valves early on. I just had to replace a non-functioning cup holder.

It seems to me that all of the intake problems are somehow related and feeding each other, but that's just a hunch.

It's very frustrating, and it's bleeding my wallet.
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2011 BMW 335d, Space Grey/Black, Sport, Premium, Cold Weather, Convenience, Nav, Harman Kardon/Sat, iPod
2010 Audi A4 2.0 Quattro P+ 6MT (Wife's car)
2004 BMW R1150RA
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  #6  
Old 09-12-2019, 06:38 AM
KeithS KeithS is offline
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Location: Central NJ
 
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Quote:
Originally Posted by Philm35 View Post
I don't drive it like a grandmother, but I don't do track days with it either. I'd say I use it pretty normally, with a good mixture of highway miles and city driving
Just as an information point, our driving styles seem pretty similar. For many years we would take a couple trips per year of 800 miles in one weekend (visiting our son, who has since moved much closer). It was on these trips we were able to hit 40 MPG.
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  #7  
Old 09-12-2019, 07:00 AM
Philm35 Philm35 is offline
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Location: Cincinnati, OH USA
 
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Mein Auto: 2011 BMW 335d
I've never hit 40mpg with my car, but I tend to drive pretty fast on the freeway. My average mileage hovers around 29, with a mix of freeway and city driving. I can get up to 34MPG on long trips, but that's usually at 80mph.

I've heard other 335d owners claim higher mileage... Maybe my intake problems over the long term have decreased my mileage.
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2011 BMW 335d, Space Grey/Black, Sport, Premium, Cold Weather, Convenience, Nav, Harman Kardon/Sat, iPod
2010 Audi A4 2.0 Quattro P+ 6MT (Wife's car)
2004 BMW R1150RA
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  #8  
Old 09-12-2019, 07:05 AM
KeithS KeithS is offline
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Location: Central NJ
 
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Mein Auto: '11 335d, '17 340iGT
Quote:
Originally Posted by Philm35 View Post
I've never hit 40mpg with my car... Maybe my intake problems over the long term have decreased my mileage.
My only symptom of carbon buildup before it finally set the CEL was reduced MPG. 40 MPG was achieved only with a clean intake system.
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  #9  
Old 09-12-2019, 10:32 AM
Philm35 Philm35 is offline
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Location: Cincinnati, OH USA
 
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Mein Auto: 2011 BMW 335d
The first time I had the carbon blasting done, there were no drivability symptoms at all, and mileage was normal. I was just getting an SES light triggered.

The second time I needed it, the engine was running very roughly at idle, but OK at driving speeds.
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2011 BMW 335d, Space Grey/Black, Sport, Premium, Cold Weather, Convenience, Nav, Harman Kardon/Sat, iPod
2010 Audi A4 2.0 Quattro P+ 6MT (Wife's car)
2004 BMW R1150RA
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  #10  
Old 09-12-2019, 10:32 AM
Philm35 Philm35 is offline
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Location: Cincinnati, OH USA
 
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Mein Auto: 2011 BMW 335d
This is the sequence of intake-related issues I've had with my D...


49717 miles 6/1/16 SES light came on, no drivability symptoms with the car. Replaced EGR cooler.
50412 miles SES light came on, again with no other drivability symptoms. Carbon buildup walnut shell blasting done.
71564 miles 8/8/18 Rough idle. #4 Fuel injector replaced.
Approx. 81,000 miles. 6/20/19 Rough Idle. Second Carbon buildup walnut-shell blasting done.
Approx. 83,000 miles (this week). "Engine Malfunction/Reduced Power" warning activated. No other driving symptoms. MAF sensor needed.
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2011 BMW 335d, Space Grey/Black, Sport, Premium, Cold Weather, Convenience, Nav, Harman Kardon/Sat, iPod
2010 Audi A4 2.0 Quattro P+ 6MT (Wife's car)
2004 BMW R1150RA
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  #11  
Old 09-12-2019, 11:39 AM
Bolosman Bolosman is offline
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Location: UK
 
Join Date: Apr 2017
Posts: 84
Mein Auto: F01 740d M Sport
Try cleaning the MAF sensor with some electrical contact cleaner.

I had the walnut blasting done on mine and as long as they're not spraying the **** everywhere with no vacuum lol it shouldn't affect the MAF

Plus, in order to greatly reduce future carbon build up I've removed all of my EGR system and had it mapped out so now there will only be fresh air plus any bits of oil that normally float around the intake system.

Last edited by Bolosman; 09-12-2019 at 11:43 AM.
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