P0313 Misfire Detected With Low Fuel Level

2002 325i, 97,000 miles.

SES light came on with 3 codes:
- P0313: Misfire Detected With Low Fuel Level
- P0171: System too Lean (Bank 1)
- P0174: System too Lean (Bank 2)

Recently (2 weeks ago), I had a friend help me go through Inspection II - replaced air filter, changed oil, everything else looked good. Had to replace oil level sensor about a year ago, but otherwise haven't had any problems.

I was relatively low on fuel (~50 miles to go) and promptly filled up when this light came on, and my last fill-up unfortunately was down wayyy too low before I got to a gas station to fill up. From my reading (http://forum.e46fanatics.com/showthread.php?p=11841843), I'm afraid that this might have clogged the fuel filter.

No whistling noises and after revving a little, the RPMs seems to come down and stabilize normally, so doesn't seem to be a vacuum leak.

Any input on this would be appreciated.

I assume the code came AFTER the fill up, right? If you haven't ran any Chevron Techron fuel injector cleaner at all I'd do it next fill up. I would also clean the MAF

The code came after the fill-up, but not immediately. Last weekend (Saturday) was when I ran it too low, and filled up fully. Yesterday, almost a full tank later (about 330 miles driven, 50 miles left on the tank), the light came on. I haven't tried any Fuel Injector Cleaner - does this need to be done on an empty tank? I did just fill up today so I have a full tank right now.....

I did notice this morning that I backed out of a parking space, then put it in Drive to pull forward, and when barely rolling forward, the car lurched 3-4 times almost sounding like it was about the cut off and die (I didn't have a chance to look down at the RPMs, but I think they were probably fluctuating low/high/low/high/low/high but then stopped doing that and it drove normally afterwards)

Also: I was low on coolant about 10 days ago, and just added some distilled water (0.5 L bottle)...I don't think this has anything to do with the code, but I figured I'd mention it.

As an update....

I haven't had a chance to add the Techron fuel injection cleaner yet, but after I did some more reading and realized where the MAF sensor is, I remembered replacing the air filter with Inspection II (not the cabin air filter, the large rectangular filter - what is this filter technically called? Intake air filter?) and with the car exhibiting somewhat of a lumpy idle since the light came on, I figured maybe that was the culprit. I purchased some CRC MAF sensor cleaner and followed these instructions http://www.bimmerfest.com/forums/sho...d.php?t=214439 to clean the sensor and screen.

After starting back up, the idle seemed to be smoother, so I've cleared the codes now and we'll see if they come back....

If the code was just indicating Bank 1 (cylinders 1-3) it is more indicative of a fuel filter/fuel pump issue since the second bank (cylinder 4-6) would still be getting enough fuel.

First, refill when you get down to closer to 100 miles left. The gas also cools the fuel pump.
The light comes on with about 2 gallons left, try not to wait that long.

At 97,000 miles, if you haven't replaced the fuel filter you should do it now.
If the code continues after a filter replacement, it may be time for a fuel pump.

Originally Posted by shanneba

Listing the actual code number would help with diagnosing your problem. if it was something like "lean with low fuel level" it would make a difference from just the normal O2 lean code.
If the code was just indicating Bank 1 (cylinders 1-3) it is more indicative of a fuel filter/fuel pump issue since the second bank (cylinder 4-6) would still be getting enough fuel.

Sorry - the 3 codes I got were P0313 (Misfire Detected With Low Fuel Level), P0171 (System too Lean (Bank 1)), and P0174 (System too Lean (Bank 2)). I've updated the OP to reflect the details.

With that, would you still think it might be fuel filter/fuel pump? So far it's been ok after the MAF sensor clean, no SES light for now....

At 97,000 miles, if you haven't replaced the fuel filter you should do it now.
If the code continues after a filter replacement, it may be time for a fuel pump.

I replaced my fuel filter at 55K (almost half your mileage) and it was already clogged up really bad. The fuel inside poured out like black coffee. MPGs went up after this.

Check your fuel pressure and volume and report back

Originally Posted by OrientBlau

I replaced my fuel filter at 55K (almost half your mileage) and it was already clogged up really bad. The fuel inside poured out like black coffee. MPGs went up after this.

To be perfectly honest, when I bought this car (used), there weren't too many records of the previous service that had been done. I've had practically no issues in the past 18 months of owning it, and everything visually seemed to be in very good condition when I bought it, so it appears that the previous owner took good care of it. Is a fuel filter replacement something that is typically done at a certain mileage? I bought it at about 75k....would there be an easy way to check whether it's been replace and/or what condition it's in without completely removing it and seeing how ugly things look?

Originally Posted by jbeurotech

Check your fuel pressure and volume and report back

Could you give some more details on how to do this? By volume, I'm not sure if you just mean the fuel level right now (about 7/8 tank), but I'm not sure how to check the fuel pressure. Thanks!

If you are going to work on your BMW, get a Bentley Manual for it.
It has details on the troubleshooting.
You can measure the fuel pressure at the fuel rail and measure the volume pumped in a specified number of seconds following the procedures in the Bentley Manual NO SMOKING!!!!!

With lean codes for BOTH banks, check for a vacuum leak first, very common on the E46s.
Searching here for the two codes should return hundreds of threads with more information.

Originally Posted by shanneba

If you are going to work on your BMW, get a Bentley Manual for it.
It has details on the troubleshooting.
You can measure the fuel pressure at the fuel rail and measure the volume pumped in a specified number of seconds following the procedures in the Bentley Manual NO SMOKING!!!!!

With lean codes for BOTH banks, check for a vacuum leak first, very common on the E46s.
Searching here for the two codes should return hundreds of threads with more information.

yup there you go!

I had exactly the same problem, reset the light and should be ok, if not check your valve cover gasket, valve cover for cracks, vaccum hoses

Thanks to everyone for the advice.

After resetting the light, about 35 miles later the light came back on, this time just with codes P0171 and P0174. Feeling around the edges of the valve cover gasket (without removing the valve cover yet), it still feels nice and rubbery, not hard/dry/plasticy. From what I understand, over time the heat causes it to turn hard and brittle, but the edges I could feel still feel fine. I suppose there could still be a crack/leak somewhere, but I got some CRC cleaner to try to check for a vacuum leak. Spraying by the intake elbow didn't have any impact on the car idling. However, here is where I did notice a difference:



Spraying at the location where I have my flashlight shining caused the engine to rev up a little. I was under the impression that by spraying near the vacuum leak location would cause the engine to sputter/rev down, so I'm not sure if I've found a vacuum leak or not....? [I apologize for being a newb, but am trying to do as much learning/research on my own as I can (i.e. learning about VCG, etc.) and sincerely appreciate the patience and guidance]

Thoughts with this latest info? Should I be thinking more along the lines of a vacuum leak or fuel filter problem? I've also seen the info on the adjuster unit (http://www.e46fanatics.com/forum/sho...d.php?t=576774) but I'd be curious for input on what seems to be most likely based on the current scenario. Thanks!

I hate to bump my own thread, but I would definitely appreciate advice on what seems to be the most likely possibility to check next....

With the lurching I've experienced at low speeds (pulling out of parking spaces), it leads me to believe that it might be a vacuum leak, but I'm not sure if other possibilities like the fuel filter would contribute that significantly.

are people really not immediately suggesting vaccum leak. while not 100% of course, those are textbook vaccum leak codes.
i would check, in this order

-all vacuum lines
-valve cover gasket (yes it can cause a vacuum leak)
-fuel filter
-it can also be MAF or pre Cat 02 sensors, but i doubt on the sensors because of the instantaneous lean on both banks
-CCV
-fuel pump

Originally Posted by g6

are people really not immediately suggesting vaccum leak. while not 100% of course, those are textbook vaccum leak codes.
i would check, in this order

-all vacuum lines
-valve cover gasket (yes it can cause a vacuum leak)
-fuel filter
-it can also be MAF or pre Cat 02 sensors, but i doubt on the sensors because of the instantaneous lean on both banks
-CCV
-fuel pump

EXCEPT MISFIRE WITH LOW FUEL!!! That code screams pressure or volume. Pretty easy check the pressure and volume of the pump and we can go from there....

Originally Posted by jbeurotech

EXCEPT MISFIRE WITH LOW FUEL!!! That code screma pressure of volume. Pretty easy check the pressure and volume of the pump and we can go from there....

Misfire with low fuel code is gone (as of the other day). I can re-check the codes and make sure it hasn't come back, but as far as I know, it's now just 0171 and 0174 (System too lean in both banks)

I know but the fact all three codes happened together the first time is the signal. Hence the reason DIY cars are a PIA because you guys clear codes then try to fix it. Give up and bring it to me with missing "puzzle" pieces....

I have 330I 2001 with like codes and have not found vacuum leak. I did replace the DISA(it was toast) and got rid of the rough idle and stalling. I will check the fuel pressure but this sounds like possible root cause. Can you guys tell me where the fuel filter and fuel pump are actually located and level of difficulty? I got 130K miles so I am sure the replacment is due. what kind of pressure should I be looking for on the injector tube side too?

CCV fouling your spark plugs.