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X3 E83 (2004 - 2010)
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  #1  
Old 09-27-2009, 12:00 PM
tmwoodall tmwoodall is offline
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Is this what a Dying MAF does?

Ok so I had my problems last week right after I purchased the X3. Well I decided to drive it and keep listening to make sure it was in fact the MAF due to not wanting to spend 240 bucks on something that was not the cause.

I started the car up and it did not want to turn over. The first time I tried to start it up after it had sat for two days it actually died and had to be restarted. Once on it did the rough idle much worse than before. Once it is warm it acts just fine.... until last night.

I noticed while pulling about 2k or so RPMs at 65(ish) MPH it was starting to kind of surge a bit like it was starved for gas or air. It was in and out like a wave if that makes sense. It was not enough that my fiancee noticed it but as the driver I could certainly feel it.

I am pretty sure it is the MAF just want to see if this sounds in line with my issues before buying a new one.
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  #2  
Old 09-27-2009, 01:57 PM
bluskye bluskye is offline
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failing fuel pumps do things like that too. Did the car throw error codes?
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  #3  
Old 09-27-2009, 03:01 PM
tmwoodall tmwoodall is offline
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Yep Running lean on bank 1 and bank 2 o2 sensors. I forget the actual codes but it is what I have read correspond to the MAF going out.
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  #4  
Old 09-27-2009, 03:24 PM
spokelizard spokelizard is online now
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OK, I give up, does someone want to explain what the MAF is and what it does?
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  #5  
Old 09-27-2009, 04:49 PM
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X3-terrestrial X3-terrestrial is offline
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Quote:
Originally Posted by tmwoodall View Post
I started the car up and it did not want to turn over.
Meaning it didn't want to crank over? That could be a low battery sign.

About the MAF, try desconnecting the plug to the sensor and see if the symptoms desappear/or improve.
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  #6  
Old 09-27-2009, 05:01 PM
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Solidjake Solidjake is offline
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Originally Posted by spokelizard View Post
OK, I give up, does someone want to explain what the MAF is and what it does?
Google works wonders..

http://www.autoshop101.com/forms/h34.pdf
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  #7  
Old 09-27-2009, 05:13 PM
eXhilarat3d eXhilarat3d is offline
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MAF = Mass Air Flow
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  #8  
Old 09-27-2009, 06:22 PM
tmwoodall tmwoodall is offline
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Im totally aware of what the MAF does, most of my symptoms have pointed to the MAF but a few have not.

It is not a dead battery it is more like on an older car where the carb needed to get some gas flowing. I am going to go unplug it right now to see if that does anything different on startup.
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  #9  
Old 09-27-2009, 06:31 PM
tmwoodall tmwoodall is offline
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Quote:
Originally Posted by X3-terrestrial View Post
Meaning it didn't want to crank over? That could be a low battery sign.

About the MAF, try desconnecting the plug to the sensor and see if the symptoms desappear/or improve.
Startup was maybe a tad better if at all, however driving it it did not like to shift correctly at all. It would down shift very harshly and not quite in the right spot when slowing down.

Last edited by tmwoodall; 09-27-2009 at 07:11 PM. Reason: More accurate description
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  #10  
Old 09-27-2009, 07:07 PM
tmwoodall tmwoodall is offline
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Starting to consider ICV???

I am fairly well versed in this stuff on my old truck, jeep, and newer truck. I just don;t have much baseline and there are not may write ups for these damn things. I only had about 30 miles before the code went off so not much to go off of.
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  #11  
Old 09-27-2009, 08:05 PM
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Originally Posted by tmwoodall View Post
Starting to consider ICV???
Why? Isn't your code P0171? That's a lean fuel mixture code and nothing to do with the ICV, which would throw P0505. Is it giving you any other codes?

I'm still thinking the MAF needs to be replaced, but that just my opinion it's really hard to diagnose a problem over the internet.

A competent Indy shop would charge around $75.00 to diagnose it, that would be the only way to be 100% sure what it is.
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  #12  
Old 09-27-2009, 08:16 PM
tmwoodall tmwoodall is offline
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Originally Posted by X3-terrestrial View Post
Why? Isn't your code P0171? That's a lean fuel mixture code and nothing to do with the ICV, which would throw P0505. Is it giving you any other codes?

I'm still thinking the MAF needs to be replaced, but that just my opinion it's really hard to diagnose a problem over the internet.

A competent Indy shop would charge around $75.00 to diagnose it, that would be the only way to be 100% sure what it is.
Ok yea time to call in the pros. I was just starting consider the ICV due to other "symptoms" read on the web. But yes that is my code that and the paring code that correpsonds to the downstream sensor.

Reason for doubt: It does not run any better and shifts WAAAAAY worse with the MAF unplugged.
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  #13  
Old 09-27-2009, 09:18 PM
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X3-terrestrial X3-terrestrial is offline
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Quote:
Originally Posted by tmwoodall View Post
Ok yea time to call in the pros. I was just starting consider the ICV due to other "symptoms" read on the web. But yes that is my code that and the paring code that correpsonds to the downstream sensor.

Reason for doubt: It does not run any better and shifts WAAAAAY worse with the MAF unplugged.
Yeah I forgot I read that.But based on the code, I will also be suspecting a bad coil as was suggested on your other thread.
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  #14  
Old 09-28-2009, 11:43 AM
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HT417 HT417 is offline
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Wouldn't bad coils create the opposite condition? Rich instead of lean?
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  #15  
Old 09-28-2009, 12:34 PM
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Wouldn't bad coils create the opposite condition? Rich instead of lean?
Reading about it, it would be a cilinder XX misfiring code. So I guess the MAF is the winner.
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  #16  
Old 09-28-2009, 01:20 PM
tmwoodall tmwoodall is offline
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I would tend to agree with the MAF conclusion, as everything else I have read with similiar symptoms usually come really close in most if not all regards EXCEPT they all run rich instead of Lean.
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