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Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 7 Series / 8 Series > 7 Series - E38 (1995 - 2001)

7 Series - E38 (1995 - 2001)

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  #1  
Old 02-12-2013, 09:50 PM
jordan101 jordan101 is offline
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Location: springfield
 
Join Date: Feb 2013
Posts: 37
Mein Auto: 1998 740il
maf problem? code p1071 p1073

First off its codes p0170 and p0173. Well my e38 runs great idles right around 600 rpm. purs light a kitten. I just bought the car had everything check over and everything was good. I drive 200 miles home and the next day those codes come on. I sprayed carb cleaner around intake gaskets but no effect in idle. I then took off maff and cleaned it. The engine light stayed off for almost 300 miles. Do you guys think the maf is bad? Oreily said the fixes are intake gaskets a maf sensor or vacuum leaks. but I don't get a lean code.

Last edited by jordan101; 02-12-2013 at 09:59 PM.
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  #2  
Old 06-06-2013, 04:00 AM
delorian delorian is offline
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Location: Stockholm, Sweden
 
Join Date: May 2007
Posts: 40
Mein Auto: Bmw 528 98
I hade the same problem, and was going to replace my maf.

Then i finally found part 19 cracked.
I was about to replace 14 also but bmw said 14 was not a component on my car.
http://www.realoem.com/bmw/showparts...95&hg=11&fg=40

That was what was causing my high fuel consumtion.
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  #3  
Old 06-06-2013, 09:24 AM
jitsjaf2009 jitsjaf2009 is offline
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Location: Hemet, Ca
 
Join Date: Aug 2012
Posts: 451
Mein Auto: 1995 325i Convertible
When I first got the 740 for my wife, I had the leaky boot, rough idle, white smoke and had already determined to replace ALL rubber and plastic gaskets, caps, hoses, osv, etc, to eliminate all questions since the intake system is so involved. After doing so, all was well, Passed CA smog test "hands Down" and still original MAF.
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  #4  
Old 06-06-2013, 09:48 AM
JakE38&Jade JakE38&Jade is offline
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Location: tulsa oklahoma
 
Join Date: Apr 2013
Posts: 40
Mein Auto: 1998 BMW E38 740il
my ses light came on and I got it checked and one of the codes were for the mass airflow sensor. does this mean it needs replaced? I tried cleaning it with non chlorinated brake parts cleaner and still the same.
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  #5  
Old 06-06-2013, 11:01 AM
jitsjaf2009 jitsjaf2009 is offline
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Location: Hemet, Ca
 
Join Date: Aug 2012
Posts: 451
Mein Auto: 1995 325i Convertible
You may get that code for air leaks after the sensor, including intake manifold leaks and major vacuum leaks. Use the carb. or brake cleaner test method to localize it.
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  #6  
Old 06-06-2013, 03:01 PM
Mayorchuck Mayorchuck is offline
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Location: Farley, MO
 
Join Date: May 2013
Posts: 641
Mein Auto: '96 740iL
Keep in mind that all codes from past or present are stored until they are cleared. If you have not had your codes cleared recently, I would do so and check them again after a drive. MAF are more often than not caused by a dying MAF. If can be caused by vacuum leaks so after verifying the code, it always best to check for leaks:

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  #7  
Old 06-13-2013, 02:49 PM
skychez skychez is offline
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Location: Washington
 
Join Date: Oct 2010
Posts: 4
Mein Auto: 2001 740i Sport
I just had the same codes on my 2001 740i

P0171 - System Too Lean (Bank 1)
P0174 - System Too Lean (Bank 2)


Spent hours trying to find a nonexistent vacuum leak - everything looked good, no idle changes while coating vacuum leak zones with carb cleaner, etc.

Cleaned the MAF (Mass Airflow Sensor) with electrical contact cleaner - to no avail. I had cleaned this sensor a few years back, and it actually got my 'Service Engine Soon' lamp to go out, but not this time around.

******THE FIX*******

Realizing that the fault codes pertain to both banks of cylinders, I decided to just replace the MAF, and you can achieve this for the cost of a tank of gas...

The factory Bosch BMW replacement part costs about $300.

After some research - mostly within Bimmerfest (THANK YOU!) - I found that a cool suggestion based on part interchangbility actually works!

The interchangeable sensor in question is meant for the VW Beetle, Golk, and Jetta MkIV. Here is a link for the specific item:

http://secarpart.com/products.php?pr...52d-06A906461A

You will notice that the factory Bosch VW MAF is much smaller than the factory Bosch BMW MAF. The actual sensor, though is the exact same and can be extracted from the VW unit by removing the (2) torx head security screws holding it in place. These look to be FIVE-point torx-plus security screws, about 25mm. I do not have those bits, and carefully removed the screws with some knipex pliers.

After removing the faulty MAF from my 740i - held in place with (2) torx security 20mm screws - I inserted the VW Bosch MAF into the orifice and seated it down with the BMW 20mm torx security screws. After plugging in the MAF harness I started the car and needless to say I was very pleased with the results - even more so after test driving.

The throttle response on ALL levels of the power band is now consistent and crisp. The hesitation I would experience when flooring the vehicle is completely absent and the acceleration is back to 100%.

Would definitely like to thank the member whom posted the alternative Bosch part suggestion earlier in the forum. It is a logical fix that saves you a lot of time, money in aimless shop hours, and remedies a car that does not perform as it should based on vague OBD fault codes.

Good luck - hopefully this helps!
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  #8  
Old 06-13-2013, 06:54 PM
Mayorchuck Mayorchuck is offline
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Location: Farley, MO
 
Join Date: May 2013
Posts: 641
Mein Auto: '96 740iL
Good catch on the part. Just note, this only applies to facelift E38's. Some detailed info:

http://forums.bimmerforums.com/forum....php?t=1615005
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