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BMW ****ie
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Discussion Starter · #1 · (Edited)
Thanks to this forum I stepped out of my comfort zone and have started accomplishing very basic work on my engine. Each small step increases my confidence for the next slightly more challenging task.

CLEAN YOUR MAF - It took a novice like me a total of 15 minutes (popping hood to closing hood).

CRC MAF Cleaner (spray can).
Basic tools (screwdriver 10 mm socket and a smaller socket size unknown - see pic below)

NOTE:

All E39 air filter housings do not appear to be the same. Mine is a 2002 530i (built late 2001).

There is a hidden screw that connects the plastic mounts for the air filter AND the section on the back side of the MAF. This screw is between the air filter housing and the engine block (right above the alternator). I do not know the socket size. Do NOT over torque it when you are done as it is embedded in the plastic housing of the air filter. Snug it tight. Don't crank it.

The red arrows are the four items you have to remove OR loosen to access the MAF.

You also have to pop open two clips between the DISA and the air filter housing (they can fall off as mine did so be careful).

My MAF sensor appeared to the naked eye as clean before I cleaned it. I have before and after pics below. I apologize as they are two different angles.

I filled up after completing this process to check my MPG after doing this. I changed my spark plugs also which factors into any change in MPG.

NEW OEM MAF $202
http://www.autohausaz.com/search/[email protected] & Air System&[email protected] Mass Sensor

Wonder what discount a group buy would yield?

EDIT: 10/15/2011

Just decided to taker her out for a spin. The response is significantly better and a preliminary check on the MPG seems to have significantly improved as well (jury still out as I have only driven 56 miles thus far). Unsure if the new plugs or cleaned MAF had the greater impact on the improved response. She puts me in the seat now when I punch it. Wow! This also indicates my DISA may be functioning properly but will change it anyway.

There are no odd sounds coming from the engine. She does shimmy ever so slightly on cold starts then smooths out within a minute or so. After that she purrs like a kitten. At 95k miles she is still a force to be reckoned with.

EDIT: 10/17/2011

Yesterday my SES light came on. The error code was P0174 (MAF, O2, or Fuel Injector). I immediately checked my work and found I had not tightened the MAF hose clamp when I was done. SES light cleared within 30 minutes. Throttle response is amazing! COLD START SHIMMY IS GONE!!!

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Seek to understand,^Value
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CLEAN YOUR MAF
For the record, see also:
- How not to remove and clean your MAF (1)
- Removing and cleaning the MAF sensor housing on the I6 E39 (Bentley notwithstanding)
- MAF Removal and Cleaning (2000 540i and 2001 525i)
- Cleaning a Mass Airflow Sensor (MAF) 2000 BMW M5
- Inspection II part II: Cleaning MAF & replacing power steering fluid

So others find this easily, I just added the following to the bestlinks:

- DIY for replacing (1) (2) (3) & cleaning your mass air flow (MAF) sensor (1) (2) (3) (4) (5) and how 'not' to clean your MAF (1) & buying a replacement MAF cheaper than the BMW MAF (RangeRover MAF) (VW MAF) (Hyundai MAF) & MAF resistance testing (1)
 

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BMW ****ie
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Discussion Starter · #3 ·

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Great Job!

However, my personal experience of cleaning the MAF is that it is short-lived.
Soon or later the MAF goes.
I agree completely, Went down the same path. 1st cleaning was good for about 10K miles, second for about 5K miles, the 3rd lasted a few minutes before setting the CEL or having driveability issues. When I finally did replace with a new MAF, car had much better throttle response and the occassional coasting to a stop stall's stopped.
 

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BMW ****ie
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Discussion Starter · #6 · (Edited)
I agree completely, Went down the same path. 1st cleaning was good for about 10K miles, second for about 5K miles, the 3rd lasted a few minutes before setting the CEL or having driveability issues. When I finally did replace with a new MAF, car had much better throttle response and the occassional coasting to a stop stall's stopped.
"Thank you" to both you and C90 (above). Based on this intel:

1) My improved response MAY be moreso due to the MAF vs the plugs (MAY).

2) I will look into a new MAF next spring (or upon degraded response) based on the numbers you provided.

Do you have a better MAF price than this?
http://www.autohausaz.com/search/[email protected] & Air System&[email protected] Mass Sensor

==> Do you (or anyone else) have a hypothesis as to apprx how many miles should the MAF be replaced (on average)?

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Can't wait to do this and see what the results will be with a cleaned MAF and ICV. I suspect my car will run much more smoothly. Thanks for the write-up.
 

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BMW ****ie
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Discussion Starter · #9 · (Edited)
Hows this (is where I got mine about 2 years ago): http://www.eaceuroparts.com/

Only says Bosch on it, no BMW logo, but otherwise was identical to the factory unit in every possible way.
Thank you for the input.
I have some potentially bad news for you...

The link you provided does NOT include the 530i MAF.

I did a part number search (13627567451) and this is what I found on that site:
http://www.eaceuroparts.com/parts/part_number/13 62 7 567 451/3

Their cost for the 530i MAF is $240

The link I found costs $202 for the same part number

http://www.autohausaz.com/search/[email protected] & Air System&[email protected] Mass Sensor

Lets keep searching for the best price as I just started pricing the MAF an hour or so ago.

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I reckon I am next in line.

I have the same symptoms for my 2003 525i with 68,000 miles. Changed the air filter which was the original one, and it was in a mess. The foam backing was disintegrating into just black dust. I think that helped some but still have the idling problem, like it wants to stop.
Have the P1083, 1085, 0171, and 0174 codes that Autozone read for me free. :thumbup:

The CRC 05110 Mass Air Flow Sensor Cleaner I ordered will be here in a few days and I am going to clean the MAF sensor and see what happens. Maybe that will fix my problem. Will let you know what happens.
 

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I have the same symptoms for my 2003 525i with 68,000 miles. Changed the air filter which was the original one, and it was in a mess. The foam backing was disintegrating into just black dust. I think that helped some but still have the idling problem, like it wants to stop.
Have the P1083, 1085, 0171, and 0174 codes that Autozone read for me free. :thumbup:

The CRC 05110 Mass Air Flow Sensor Cleaner I ordered will be here in a few days and I am going to clean the MAF sensor and see what happens. Maybe that will fix my problem. Will let you know what happens.
Clean the ICV if you're car has one. My car runs like a dream now after I cleaned mine. I'll be cleaning the MAF shortly as well.
 

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I've got an oil change and spark plug job this weekend. Was going to clean the MAF as well (have only done this once before and that was a year ago). To be honest, I do the MAF clean as preventative maintenance but have not experienced any issues with the engine that could be attributed to it.

My question is, is cleaning the MAF actually going to cause more damage than simply leaving it alone (for those that have no issues related to the MAF)? I guess this question is somewhat related to the age old question, 'should I change the transmission fluid in my auto tranny, even though it says lifetime fluid or if it ain't broke, don't mess with it?
 

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What is the ICV and how will I know if I have it on my car.
The ICV is the Idle Control Valve, it has a lot to do with how the car starts and runs when cold and it also affects acceleration at times. I believe your car should have one because they are present on 528's. Here are some DIY's: http://forums.bimmerforums.com/forum/showthread.php?t=928735 http://forums.bimmerforums.com/forum/showthread.php?t=589747. The second one is what I used for my 540i. The placement of the ICV on the V8 is much more easily accessible, but it's somewhat hidden away on the I6.
 

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I've got an oil change and spark plug job this weekend. Was going to clean the MAF as well (have only done this once before and that was a year ago). To be honest, I do the MAF clean as preventative maintenance but have not experienced any issues with the engine that could be attributed to it.

My question is, is cleaning the MAF actually going to cause more damage than simply leaving it alone (for those that have no issues related to the MAF)? I guess this question is somewhat related to the age old question, 'should I change the transmission fluid in my auto tranny, even though it says lifetime fluid or if it ain't broke, don't mess with it?
Good question, I'm curious as well. I've heard cleaning the MAF can result in a shorter lifespan.
 

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I've cleaned the MAF on my 528iT without any subsequent problems. I wasn't having any symptoms or codes before doing so, thus noticed no change in operation afterward. I don't think you'll shorten the life as long as you don't do it frequently or (obvously) damage the element.
 

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I've cleaned the MAF on my 528iT without any subsequent problems. I wasn't having any symptoms or codes before doing so, thus noticed no change in operation afterward. I don't think you'll shorten the life as long as you don't do it frequently or (obvously) damage the element.
:thumbup:
 

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Test them before you clean/replace

Nice timing on thread - I've just started considering the MAF issue.

According to the crew over at M5Board, there is a way to check your MAFs via the unlocked cluster. Haven't done yet, but will be doing this weekend.

Directions below, and I've attached the spreadsheet for the temp and barometric translations. I'm not sure if this is applicable to all E39s -- apologies if not.

Edit - For some reason I can't upload translation table -- here's the link: http://www.m5board.com/vbulletin/at...-correction_for_peak_fuel_flow_data_ver_3.xls

Edit #2 -- be careful looking at your nav screen while traveling at WOT.

Update Edit #3 -- darn hard finding a place near me to go WOT.

Select the mode for fuel consumption per hour. (Screen 04)
With the engine fully warmed up, drive several WOT (wide open throttle) accelerations. Notice the fuel flow per hour numbers. If everything is ok the numbers should increase continously to about 140 litres per hour at WOT at 7000 RPM. (don´t worry about bouncing into the rev-limiter)

The fuel-flow is directly proportional to the MAF reading reported to the Engine Electronics, so if the Fuel-flow is correct, the MAFs are most likely correct too.

To be able to compare your fuel-flow readings with other people´s readings,
you need to correct the data for temperature, barometric pressure and altitude. This is easy: look at the table attached at the bottom of this sheet.

Look up the two factors matching your temperature, barometric pressure and altitude. Then multiply the reading from the instrument cluster with both those factors. The result will match what the fuel flow number would have been at sea-level, +20 deg C and normal barometric pressure.
 

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BMW ****ie
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Discussion Starter · #19 ·
Nice timing on thread - I've just started considering the MAF issue.

According to the crew over at M5Board, there is a way to check your MAFs via the unlocked cluster. Haven't done yet, but will be doing this weekend.

Directions below, and I've attached the spreadsheet for the temp and barometric translations. I'm not sure if this is applicable to all E39s -- apologies if not.
[/B]
Nice test info. Great writeup. I think this info should be a best links DIY MAF test procedure.
 
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