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-   -   P0172 and or P0175, engine bank 1 2 running too rich, I have solutions :) (http://forum.e46fanatics.com/showthread.php?t=919568)

mmmusty 05-03-2012 05:31 PM

P0172 and or P0175, engine bank 1 2 running too rich, I have solutions :)
Whats up ladies and gents, so after having the P0172 and P0175 codes on my car for more than half a year, after an engine swap, after many other "common" parts swapped, I have found the solution(s)!

I have devised a somewhat systematic, cost-effective as well as intelligent way to go about fixing this issue.

I searched forums, took my car to the best indy shops that i wont mention, both calabasas bmw as well as beverly hills bmw... talked to a few forum members and i had not reached my solution as noone completes this after they fix their problem it seems and because the codes refer to multiple possible problems.

at any rate, im offering my help and knowledge on the subject to anybody that has this pain-in-the-ass issue and will gladly lend my hand if i can be of service to anyone. feel free to send me a PM as im not on the site often

taylor192 05-07-2012 03:46 PM

So you wanna help... yet you don't post the solution. Come on dude, WTF?

mmmusty 05-07-2012 04:08 PM

the reason why i have not written down the solution, is because there is NOT one simple solution, it varies depending on symptoms and your case... why i say people message me or reply to the thread so i can understand the specific case of the car. from there, i believe i can sort out the solution(s) pertaining to your individual case.

tell me specifics or else you would be going through the same thing as me and many others have and just throw parts and money at the car until something worked or you give up!

im only trying to help here my friend

mmmusty 05-07-2012 05:13 PM

thanks to the wise words of taylor192... i will try to write something out as he made a good point to the use of the forums.

Lets begin with a great site to decipher what the codes are and what they mean can be wrong, btw, both p0172 and p0175 are the same codes but on different engine banks. ENGINE BANKS 1 and or 2 RUNNING TOO RICH. http://www.obd-codes.com/p0172

1. for starters check your AIR FILTER and FUEL FILTER and replace as necessary as these parts would need to be replaced regardless if they are dirty and clogged and they can be the reason the codes are up. if replaced, then reset codes and drive to see if the codes come back... PARTICULARLY in the case of the FUEL FILTER.

2. Next thing is you want to do is a vacuum leak test or at least an inspection of the common areas of leaks on our cars. you want to inspect these areas in particular, at least visually yourself: the housing of the air filter (the black box), the piping particularly where the folds are of the air filter housing and pipe. The INTAKE MANIFOLD, and the rubber hoses that connect from the manifold to the throttle bodies. again, if there was a leak that you have fixed, RESET CODES, DRIVE.

3. NEXT, you want to pay for or have a thorough ECU diagnostic done which can show: MAF functionality, O2 sensors, fuel trim levels, etc. this is the most important part as far as im concerned as this will eliminate the need for swapping out parts that are otherwise the FIRST THING most shops and dealers will tell you--> MAF in particular, as well as confusion and shots in the dark.

once you find out what IS and what IS NOT working properly, ie: O2 sensors functioning, MAF readings are in range, then you can move onto other vague problems such as fuel delivery problems.

4. one problem CAN be your MAF (mass air flow doesnt react fast enough, or the readings are not good), FIRST BEFORE BUYING, try to replace yours with someone else who has no issues, RESET ADAPTATIONS, then drive the car to see if the symptoms remain and/or the codes come back. if not, then you can try to CLEAN YOUR MAF first with the MAF cleaner sold at most auto parts stores, and if that didnt do the trick, replace the MAF. also noteworthy here, some state that oiled filters such as K&N can cause an oily build up on the sensor of the MAF which can cause faulty readings... i swapped mine for the stock.

5. Ok, so now we are assuming that all of the above mentioned parts and issues have already been checked and are working properly... next place that was MY issues was in the fuel delivery. you want to start off with as much of a VISUAL INSPECTION OF THE FUEL LINES as possible, check for cracks, tears etc. Now lets assume that fuel lines and hoses are good...

i had jerky accel particularly in the lower RPM range, hesitation on the throttle, very rough and surge idle ONLY when i start the car for the FIRST TIME cold, and loss of power and smoothness. this again helps if you have a friend to swap parts with briefly before dumping money into parts that dont need to be changed. if you have some or all of my symptoms, i would go straight for the FUEL PUMP, especially if your car some miles stacked.

FUEL PUMP was my issue, and i opted for: http://www.highflowfuel.com/c-173565...pumps-bmw.html

im running it on my car now and here are the advantages and the reasons why i chose it over the walbro 255 and the stock pump.
a) performance in relation to the WALBRO pump and stock pump (supposedly!) ... and so far, i must say, its phenomenal!
b) lifetime warranty!
c) very inexpensive particularly in relation to the stock unit which you apparently MUST BUY with the whole unit (housing and fuel gauge included).

So, change fuel pump with a buddy or replace yours, reset codes and drive. my car was good after that... now lets say that everything else is good but you still have issues... the FUEL PRESSURE REGULATOR would be the next and final part... swap or change, reset, drive!

at this point, you should have checked in order:
1. fuel filter and air filter
2. vacuum lines and hoses, AND FUEL LINES.. shouldve put that with the rest of the hoses and lines
3. diagnosed the car if you dont have a buddy to swap parts with freely
4. MAF
5. fuel pump
6. fuel pressure regulator

hopefully its not your cats or O2 sensors from the beginning as those are the most expensive and difficult fixes... but at least with the diagnosis you should be able to tell if they are working properly.

the main thing i hope to pass on to people is to not just jump to the first thing that ALL SHOPS told me--> MAF, CATS, O2 sensors...

i hope this was helpful, apologies if it wasnt, this is my first time writing something like this... but as stated at the start of this thread, please feel free to message me so i may be able to help on your particular case

good luck with this annoying problem lol!

taylor192 05-07-2012 05:22 PM

Awesome post! Thanks! and you said it would be hard to summarize :)

taylor192 05-07-2012 05:23 PM

Did you ever read the BMW codes using a Peake reader? It'd be nice to know what the BMW codes were, not just the standard OBD-II codes.

mmmusty 05-07-2012 05:27 PM

I used my general one which is just generic codes for p0172 etc.... actually never knew that the bmw peake reader was different than the general code reader! what does the peake reader show??

taylor192 05-07-2012 05:41 PM


Originally Posted by mmmusty (Post 14369862)
I used my general one which is just generic codes for p0172 etc.... actually never knew that the bmw peake reader was different than the general code reader! what does the peake reader show??

It shows more specific BMW codes than the stand Pxxxx OBD-II codes. For instance on the car I just read there were 2 OBD-II codes, P0172 and P0175 yet 6 BMW codes: AE, AF (mixture adaptation on both banks), D0, D1, D5 (multi misfires during warm up, cylinder 4 and 5), and 48 (Vanos intake retard valve).

The Vanos code stands out and could save him replacing other parts when its just a bad solenoid - thus why it would've been interesting to see your code. Maybe you had a BMW code that stood out that could've pointed to the fuel pump. Oh well. :)

mmmusty 05-07-2012 05:50 PM

thats awesome, i wish i knew about that earlier. but i had my codes run by other shops and the dealer.. i didnt have anything else and i was told by both shops (one of the best in Los Angeles) and two dealers that my MAF was the culprit, so much so, that despite telling them that ive already swapped it out, they insisted that was the issue again! i swapped it out through warranty again... then i went on my own, as all the shops generally want you to do is leave the car with them until they swap out enough parts and do enough labor until there is nothing else left to change and no change left in your pocket... they look almost superficially at the problem whereas something like these codes which is vague requires symptoms and thorough diagnosis. do you have any recommendations on where to pick up the peake code, i found them for 150 roughly, anywhere less expensive??

taylor192 05-07-2012 05:55 PM

I picked one up used for $100. $150 seems steep considering it doesn't do much more than my $30 OBD-II code reader, yet the information is gives is invaluable.

amw-bmw 05-09-2012 12:33 AM

I recently undergone engine swap as well in my e46 vert. It keep throwing p0172 and p0175 codes after replacing air filter, MAF sensor and and all intake house...... and still tripped codes ......then one day, it was gone and hasn't been back.....#crossingfingersitdoesnt comeback

Sent from my DROID BIONIC using Bimmer App

mmmusty 05-13-2012 03:49 PM

how long after you replaced those parts did your codes go away?? or how many miles of driving and under what conditions... i have another theory about that which im hoping you can confirm...

amw-bmw 05-14-2012 02:56 PM

Well after about a 100 miles or so i figured it would clear itself. But it didnt. So i took it back to the mechanic to clear codes but after doing so codes came back within a couple of daysi figured it might be something I would just have to live with. But after about three months started the car and codes where gone.

amw-bmw 05-14-2012 03:08 PM

For a month I drove it cautiosly. But after that....anywhere from 75-105mph... :)

7to3_enthusiast 05-14-2012 08:05 PM

I had the same codes. Replaced my air mass sensor and after 300 miles it went away.

mmmusty 05-14-2012 11:55 PM


Originally Posted by amw-bmw (Post 14392434)
For a month I drove it cautiosly. But after that....anywhere from 75-105mph... :)

so after the codes came BACK from the mechanic resetting it, they just went away on their own WITHOUT you even having to reset it??

mmmusty 05-14-2012 11:56 PM


Originally Posted by 7to3_enthusiast (Post 14393392)
I had the same codes. Replaced my air mass sensor and after 300 miles it went away.

you sir, are ****en lucky lol! congrats though :thumbsup:

amw-bmw 05-14-2012 11:56 PM


mmmusty 05-15-2012 12:03 AM


Originally Posted by amw-bmw (Post 14394161)

ok, so that actually confirms my theory... basically, i think when it comes to rich and or lean codes, the ECU has adjusted air/ fuel to compensate for the vacuum leak and or the fuel pressure accordingly, for example if you have a vacuum leak, the ECU asks for more fuel, which it gets... then even after you fixed your leaks and or the MAF, the computer takes time again to ADJUST to the new or proper air intake, which would cause you to trip codes for a short while, after which, once things are adjusted to normal, the codes will stay away and the car runs great.

on my car, even after the fuel pump was changed, the car ran great... but then i got codes for complete opposite of engine running too rich, i got too lean codes!!

i figured it could need a bit more driving to adjust the system as i reset codes directly after swapping the pump. ive put on over 100 miles of canyon driving, heavy traffic, multiple cold starts and normal and hard driving and the codes have not come back!

this is just my theory, i am by no means an expert on cars, but just from my observation and thought process thats what i come up with and seems to be that both of our cases prove that

andrey.kvotchenko 05-15-2012 06:30 AM

What if your getting 0172 and 0174 which one means lean and other rich!!!

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