Intermittent E46 snottiness

[BasilRathbone]

2003 BMW 325i Saloon E46 / M54 Engine


Last spring (2018) I
replaced my O2 Sensors
rebuilt the DISA valve (vane and vacuum diaphram)
cleaned out the idle control valve
replaced split intake runners


The car passed DEQ and has been running without problem(s) for over 10 months now.


The "Check Engine" light came on around the beginning of February this year. My Peake tool sez' the O2 sensors are hitting their limits and all six cylinders show misfires.


The issue comes and goes, it's not constant. The car won't idle when the problem presents itself. The car will start but dies as soon as I let up on the gas.


And then the problem will disappear, the CEL will turn itself off and everything will go back to working like it always has.


I don't know where to start looking. Intermittent DISA valve? Failing Idle Control valve?


Peake R5/FCX(3) Code Readout


19 Code Table
E4 O2 Sensor Adaption Limit, Cyl #4-6
E3 O2 Sensor Adaption Limit, Cyl #1-3
CB O2 Sensor Control Limit, Cyl #4-6
CA O2 Sensor Control Limit, Cyl #1-3
F0 Misfire, Cyl #3
EE Misfire, Cyl #1
F2 Misfire, Cyl #5
F3 Misfire, Cyl #6
F1 Misfire, Cyl #4
EF Misfire, Cyl #2

[MarcoZandrini]

How old is the fuel pump? When was the fuel filter last changed? The filter contains the fuel pressure regulator. The fuel pressure has to be at least 50psi under all engine speeds and loads.

What causes misfires:
- old/wrong spark plugs
- bad coil
- crapped up/dirty/bad fuel injector
- failing fuel pump
- blocked/bad fuel filter
- bad fuel pressure regulator
- poor compression
- bad crankshaft position sensor
- mechanical issues such as a burned valve.

The first step in properly diagnosing a problem is to scsn the engine computer (DME) with a proper scan tool. The Peake tool is ancient history.

[BasilRathbone]

MarcoZandrini

I also replaced the fuel filter last spring while I was doing the O2 sensors.

I'd buy the 'fuel' scenario if the car was snotty under acceleration or cruise but it's only snotty at idle.

I'm leaning more towards an Idle Control Valve that intermittently gets stuck in the wide open position.

I'd really rather it be something else 'cause , as you know, it's buried so deep in the intake. Sigh!

What do you consider 'a proper scan tool'?

Any software scan tools worth a hoot (coupled with which ELM327 Adapter actually works)?

[RobertDenali]

Your codes say otherwise. Freeze frame data would be interesting. You can clean your ICV with ICV cleaner and brake kleen. Remove it from the intake, clean it and then reinstall.

It will take you about an hour.

[MarcoZandrini]

Get the OBDFusion app for your smartphone or tablet. Then head over to E46Fanatics and search for threads that mention OBDFusion and in which jfoj has commented. He’s the guru.

The O2 sensor codes are saying that the fuel/air mixture is way out of whack.

[jclausen]

I have never had to replace a idle control valve on an e46, I've seen lean faults for fuel pumps acting up