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Discussion Starter · #1 ·
hey guys, i'm new to BMW cars and society, just got my car couple weeks back. it's a E46 325CI 2002, automatic transmission (yeah i know automatic tell me about it!! but couldn't find a manual car in mint condition)
anyways i'm having troubles with the Mass Air Flow Sensor. the engine does not idle correctly (that's often not on a regular basis), somewhat bad mpg and i guess not its optimum performance. the "Service Engine Soon" is on, obviously.
i went to a mechanic who's a friend, told me that it cannot b cleaned or whatever, it needs to b changed. i googled this and found that there's a cleaner called CRC that would fix this issue without changing the sensor, any ideas?
thanks :)
 

· Coyote Racing Team
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Honestly it can't hurt to try the CRC Mass Air Flow Sensor Cleaner.

Pick up a can at your local auto parts store and follow the directions. $4 and very easy to do yourself. If it fixes it, GREAT! If not, you're only out $4 and 1/2 hour of time.
 

· Coupe OR Never
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Yes, it cannot hurt to use CRC MAF sensor cleaner and it is very cheap and easy but do not expect miracle from it. It could very well be your MAF sensor on its way out or could be something else like torn air intake boots or bad O2 sensors(pre-cat).
I would get the codes read out. Why don't you do that first and let us know. You could get lot more and specific help with some codes...

I have the same exact car you have even the model year same...
 

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Discussion Starter · #7 ·
2moro i'm gonna get it scanned and see what's really goin on.
i did some research on the CRC on how to use it and the feedbacks, if there's hope the CRC will do its work, keepin my fingers crossed....
oh btw "iskoos", ur car is auto or manual? what's ur mpg? mine now is barely doin 60mpg!! could the MAF/O2 sensors cause this ?
 

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2014 535d xDrive
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I had irregular idle as well. If you are spewing the dreaded 1074 1071 codes, along with others I would highly recommend doing the following as well while you are in that neighborhood. Clean your idle control valve. While you are in there check the butterfly flap (you'll recognize instantly when you go after the idle control valve) and clean it. Make sure to buy the connector tubing as it will probably crack when you go in (I have no idea what the tubing is for but your dealer should sell it, it's expensive! $20 a meter, but I got them to cut me a small 3" piece for free) Replace the air duct that connects to the idle control valve (it's $18 and if it isn't cracked so what you spent $18 too much, better than getting in there and realizing its cracked to hell and don't have a replacement). Might as well replace the air filter too. CRC also makes an idle control valve cleaner. This should take you about 2 hours to complete and about $50 in parts with the CRC, intake, and if ur lucky a free piece of tubing. There are DIY's on all of these things in this forum. If you do a search for my name and my posts you will see I listed the DIY's on a similar post. Only "funny" tools you need are the TORX but you should buy a set anyway for any work you are doing on your car. I did all this along with some other things (fuel filter, thermostat, oil change, coolant flush) and all of my codes have gone away and have not been back for a week or so now, that's a couple of tank fulls.

Good luck to you and don't be scared, just read the DIY's carefully and follow the instructions. They will walk you right through it.
 

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Discussion Starter · #11 ·
ok here's what i got on the scanner: "168 Thermostat, map cooling, mechanical, jammed open"
btw after cleaning the MAF sensor i got that error. so they were probably affecting one another :dunno:
about the idle problem, when i'm stuck in traffic, it gets really cranked up when i'm on Drive gear and standing still, when i'm on Neutral it's totally fine, is this normal? and will solving my problem help with the idle problem? and which sensor should i change to solve this? this is the first time i'm workin with this mechanic so i wanna b sure he's doin a right job and not doin some experimentations on me:rolleyes:
 

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ok here's what i got on the scanner: "168 Thermostat, map cooling, mechanical, jammed open"
btw after cleaning the MAF sensor i got that error. so they were probably affecting one another :dunno:
about the idle problem, when i'm stuck in traffic, it gets really cranked up when i'm on Drive gear and standing still, when i'm on Neutral it's totally fine, is this normal? and will solving my problem help with the idle problem? and which sensor should i change to solve this? this is the first time i'm workin with this mechanic so i wanna b sure he's doin a right job and not doin some experimentations on me:rolleyes:
Replace your thermostat, reset the code. Then take it from there.
 

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Discussion Starter · #13 ·
thermostat changed, no more SES signal :)
but i still get that idle problem a few times, do 325 engines suffer from this or is there anything wrong? cuz nothin's showin wrong on the scanner...
btw it's doin around 18.5mpg on average, is this reading standard, good or bad?
thanks :)
 

· a man made of men like me
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18.5 isnt low enough to cause concern. I think the average is 20 but the older the car gets the more likely that average will drop. I average around 19mpg right now :dunno:
 

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Discussion Starter · #18 ·
cleaned the MAF sensor and now she's makin in the 18 neighborhood, i guess this is the best i can get out of her :dunno:
and the engine is idling alright now :thumbup:
 
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