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BMW or MINI Spark Plug Fouling – Misfire Fault Codes P0300, P0301, etc.

Jul 30 14

Are you having trouble with random or specific cylinder misfire fault codes?  These OBD-II fault codes can often be troublesome and difficult to track down and eliminate.  OBD-II fault codes for ignition misfires are commonly displayed as shown below:

P0300 – Random misfires; this is indicating that the engine management system is detecting misfires intermittently on multiple cylinders.

P0301 – Misfire on cylinder #1

P0302 – Misfire on cylinder #2

P0303 – Misfire on cylinder #3

P0304 – Misfire on cylinder #4

P0305 – Misfire on cylinder #5

P0306 – Misfire on cylinder #6

P0307 – Misfire on cylinder #7

P0308 – Misfire on cylinder #8

P03xx – Misfire on cylinder #xx, where the cylinder number is the last two digits of the code.

Today’s engines are designed to run within very tight parameters in order to satisfy emissions requirements.  Small variances in system functions can trigger fault codes through the OBD-II (On Board Diagnostics, v-2) monitoring system.  While there may be genuine problems within the engine management system,  keep in mind that short-trips, slow driving and prolonged idling can compound cylinder misfire issues, by not allowing the spark plugs to work at the higher temperatures required for “self-cleaning”.  In these cases, an otherwise properly functioning engine can generate misfire fault codes due to minor spark plug fouling.  Therefore, engines that see these types of conditions may need more frequent spark plug changes.

If you have fault codes for specific cylinder misfires, the first step is to swap the ignition coil assembly from the indicated cylinder, with the coil assembly from another cylinder.  Next, clear the fault codes and drive the vehicle.  If the fault code now comes up indicating the new cylinder location (the cylinder that the coil was moved to), you can assume that the coil assembly is at fault and replace the coil.  If the original fault code returns (same cylinder as the original misfire code), you can assume that the fault involves this specific cylinder.  The fault could be a fouled or worn spark plug, fuel injector problem, vacuum leak at this cylinder or a mechanical problem within the cylinder (leaking intake or exhaust valve, carbon build-up, etc.).

If the fault code returns to the original cylinder, after the coil swap and code clearing (as noted above), the next course of action should be to inspect the spark plug.  The plug may be worn or fouled, causing the misfire.  If the spark plug looks visibly fine (if not, replace it), swap it with another cylinder, similar to the coil swap.  Clear the fault codes and see if the fault returns.  In the same manner as the coil swap, test, if the fault code moves to the new cylinder, replace the spark plug (in fact, you should just replace them all, in this case).  If the code returns on the original cylinder, further testing and diagnosis will be required in order to determine if the fault is caused by the fuel injector, a vacuum leak or an issue within the cylinder.

If fault codes for random misfires are present, this could be fouling or worn spark plugs, arcing coil to spark plug connector boots or weak coils in addition to other engine management system faults.  If the spark plugs have more than a few thousand miles on them, it would be wise to pull them and have a look at the electrodes and the center electrode insulator for wear or a buildup of deposits.  If in-question, replace them, especially if the vehicle sees a lot of short trips and/or idling time.

Spark plugs and ignition coils:

Fault code readers and reset tools:


BMW E63 E64 6-Series LED Angel Eye Bulb Install – How To

Jul 24 14

This install guide covers installation of the LED upgrade Angel Eye (Halo) bulbs on the E63 and E64 6-series models 204 thru 2007 (645ci, 650i, M6 coupes and convertibles).

Click below for the install guide:
BMW E63 E64 LED Angel Eye Install

Click below for LED Angel Eye Bulb Kit:


Bavarian Autosport



AFE Power Hits The Dyno for New BMW M4 Intake and Exhaust Upgrades – Video

Jul 21 14

aFe Power – Here’s a couple videos and some inside photos in the development of new intake and exhaust upgrades for the BMW M4.

Click below for aFe performance intake kits for your BMW or MINI:

Click below for aFe performance exhaust kits:

aFe POWER is well known to BavAuto customers, for it’s BMW performance intake, exhaust and programming upgrade product lines.  aFe has just purchased the all-new BMW M4 and has begun work on it already.  This is the first step in a complete build of the M4, starting with the intake system. The M4 features an asymmetrical dual intake path feeding the S55 twin turbo inline 6-cylinder engine. Starting with 430hp and 406lbs x ft of torque makes for a great baseline, but aFe POWER will have plenty to add to that when they are done.

The BMW S55 engine steps down in displacement from the previous gen M-series, but increases the torque by 111 lbs x ft of torque, and holds it from 2000 to 5400 RPM, making this new platform pull hard and seemingly never give up.  As you can see things are also a tight fit in the S55 engine bay, especially with the carbon fiber strut tower brace that sweeps across the front.

Beginning the process of tearing into the engine, doing measurements and 3D scanning, which will enable afe engineers to bring the engine into a fully CAD environment, designing the intake in a virtual space, before even creating the first articles.  From there they will be able to print and assemble parts from their in-house 3D printers, they can then verify fitment, ease of installation, and even dyno test differing designs to ensure we make the most horsepower possible.

Below are some additional photos, as well as a very short clip of what the 3D scanner looks like in action, creating a 3D model of the engine space. aFe engineer Christian is seen here scanning the M4 into his computer and will bring that scan into SolidWorks as the intake begins its life.