[PHMichel1]

Hello all,

First time posting on the forum, so let me know if there is a better place to put this. I have a couple of questions that hopefully someone can answer. I have a 2006 E90 330i, with ~142,000 miles (first BMW, and loving it). Only modifications are an AFE intake, and SuperSprint catback (connecting pipes, section 2 with performance resonators, and performance muffler). Owned the car for almost two years now and just starting to run into some minor problems with it. I have the "service engine soon" light on, and according to a basic ACTRON OBD reader I have, it is for two P0172 codes (bank 1 cylinders too rich). One is confirmed, the other is pending. The car drives otherwise fine, but does seem to be a little down on power at times, although this could very well be psychosomatic. Additionally, the engine will exhibit a bit of a strange behavior when under moderate to heavy acceleration. Like I said, car will seem slightly down on power/hesitant, particularly when below 3k rpm, but at times, when the engine hits about 3k, the power will noticeably jump. I don’t want to describe it as a surge, as that seems too extreme, its just a slight hesitation below three grand and/or a dead spot in power around 2,500 to 3,000rpm.

Due to a slightly limited budget at the moment, I want to avoid spending money on needless diagnostic costs and/or labor to replace seemingly simple parts (MAF, VANOS solenoid, O2 sensors). I think I may have more than one issue going on, but my first inclination in regard to the lack of smooth power delivery, is that I have a VANOS issue, as it feels as though the engine struggles to move the cams to the appropriate profile based on driving conditions. Not sure if that would contribute to P0172, but I am going to try cleaning the Vanos solenoids to see if that changes anything. Then I am going to clean my MAF, to see if that helps the code.

So my questions for you guys are these. First (i'm pretty sure this is a dumb one), if I clean the solenoids, and the MAF, do I need to clear the codes using the OBD. In other words, if either of those fixes the issue, will the computer clear the code automatically or do I need to clear it and then see if it comes back (never worked with an OBD before). Second, using the OBD live data, do any of you know what I should be looking for in regard to O2 sensor voltage and MAF grams/second numbers in order to potentially identify the source of P0172 code? Basically, what would those numbers look like from a healthy part? Or are there any other numbers I can look at? I know there could be other sources of the rich condition besides a faulty 02 sensor and/or MAF, but I figure those are the easiest things for me to fix on my own. If it is something other than that, like fuel injectors or something, I will leave it up to the shop. Just want to rule out something that I might be able to do on my own so I might save a few bucks.

Sorry for potentially drawn out post there, but thanks for the help.

[ctuna]

Get a Inpa/Ista D setup see the coding subforum for the
cost of a cable and your time to set it up on a PC.
Ista D is what BMW used for years at the dealership.

https://www.e90post.com/forums/showthread.php?t=1531814