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BMW and MINI DIY Video, How to Remove Stuck Spark Plug Connector Boots

Sep 30 16


BMW’s and MINI’s use of “coil-on-plug” ignition coils has been great for improved engine management and efficiency, allowing longer “saturation” times for higher energy sparks and more precise spark timing control for increased engine efficiency and improved fuel economy.  All this while also reducing the servicing requirements of the ignition system by eliminating the ignition wires (spark plug wires), distributor cap and rotor (heck, the whole distributor, for that matter!) and associated hardware.  However, the newer 4 valves per cylinder, hemispherical cylinder head designs with the spark plugs centrally located in the top of the combustion chamber have created a new maintenance problem with the coil-on-plug ignition coils.

Due to the higher heat and longer service intervals, the spark plug connector boots that connect the ignition coils to the spark plugs (replacing the connector boots on the old-style spark plug wires) can tend to glue themselves to the spark plug insulators (the ends of the spark plugs).  This is especially troublesome since the spark plugs are buried deep in the recessed tubes in the cylinder head, below the coils.  If you work with these later engines long enough, you will experience spark plug connector boots that will not pull off of the spark plugs.  In these cases, you cannot remove the spark plug until the boot is removed, as the spark plug socket will not fit down over the stuck boot ….. or even the remains of a ripped boot.

At BAVauto®, we get calls from our customers (it seems like every day) who have at least one boot that will not pull off the spark plug.  In many cases, they have been fighting with the offending boot for some time before calling us for that, hoped for, magic formula to get the boot (or what’s left of it) off so they can finish the spark plug or coil replacement job.  Well, as it turns out, we do indeed have a magic formula and we want to share it with all of our fellow BMW and MINI owners.  Check out the steps we have developed to remove stuck coil/spark-plug boots.

Click below for BAVauto Pick Tool Set:

Click below for CRC Silicone Spray:

Click below for Silicone grease:


1)     If you have the earlier style bolt-on coils that utilize a separate spark plug connector boot and the boot has stayed behind when the coil was removed, first try to pull the boot off with needle-nose pliers.  If you have the later style coils (we call them “pencil” coils) that have integral connectors with just a short boot/sleeve at the bottom, and the boot/sleeve has pulled off the coil end or ripped and left a partial section on the spark plug, go to step 3.


2)    If the pliers just rip the boot, grasp the center electrical connector portion of the connector boot and pull outward.  If the complete boot comes out, great!.  If the electrical connector pulls out, go to step 3.

 3)    Now that we have a hollow boot, we can apply a shot of spray silicone into the boot.  After spraying the silicone insert a long pick tool or small flat-blade screwdriver down through the boot.  We want to gently force the tool between the inside wall of the boot and the spark plug insulator.  This will break the seal and allow the silicone to seep between the plug and the boot.

4)    Use the needle-nose pliers or long pick tool to pull the boot off the spark plug.

5)    When installing the new parts, apply a small dab of silicone grease to the inside of the connector boot or sleeve before assembling on to the spark plug.  This will prevent future boot removal problems.

Bavarian Autosport

BMW and MINI DIY Video, Why You Should Change Your BMW or MINI Spark Plugs Before the Recommended Intervals

Sep 30 16

BMW has employed some form of vehicle service reminders for the past 35 years, or so.  Initial reminders are as simple as a mileage-driven light on the dashboard saying it’s time to change the oxygen sensor, to the common ‘80s and ‘90s systems that told us to change the oil or see our BMW dealer for a “service” or “inspection”.  Maintenance intervals for today’s BMWs and MINIs rely heavily on what BMW calls CBS (Condition Based Service).  The CBS program computes service and replacement intervals for various vehicle systems based on inputs from sensors, vehicle mileage and vehicle use.  The CBS monitors various vehicle systems for service, such as; engine oil, brake pads, brake fluid, cabin micro-filters, spark plugs and overall vehicle inspection and service intervals.  While the built-in service reminders (regardless of which version is in use on your BMW or MINI) can help assure that the vehicle receives at least some level of maintenance, these reminder intervals are typically longer than desired for an optimum vehicle life cycle.  The reminders really should be viewed as the absolute minimum service intervals and certainly not the intervals for maximum systems longevity.

One good example of extended service intervals is the engine spark plugs. Current models run with spark plug replacement intervals at about 100,000 miles.  The spark plugs actually wear as a part of their function in producing a spark.  When the spark is produced, a small amount of metal from the electrode is removed (or, worn away).  Over the millions of sparks produced in just 30,000 miles of driving, the electrodes will start to show physical wear.  As the electrodes wear they become rounded and the gap increases.  The increased gap is an obvious issue in reducing spark energy and consistency, but the rounded electrodes actually have more of a degrading effect on the spark than the slight gap increase.  Add the two together and we start to see a general degradation in engine efficiency.  We may even start to experience noticeable misfires.

While the spark plugs used today, as well as improved engine management, do allow longer service intervals than the BMW recommended 30,000 miles from the ‘80s, we have consistently found that the 100,000 mile recommendation is well past the optimum spark plug life cycle.  While the plugs may still be operating acceptably, in general, they may be experiencing random misfires and reduced spark energy.  This is due to the normal wear of the electrodes.  We may see this degradation as a noticeable miss in the engine or generation of an engine management fault code (CHECK ENGINE or Service Engine Soon warning light).

So what can you, the BMW or MINI owner, do about this?  Replace your BMW’s or MINI’s spark plugs at a shorter interval.  With experience, we recommend replacement between 30,000 and 40,000 miles to ensure maximum fuel efficiency (fuel mileage) and engine performance.  Check out the samples of spark plugs that we recently pulled from three different vehicles.  Coincidentally, each of these sets of plugs had between 30,000 and 35,000 miles on them.  All were exhibiting noticeable engine misfires.  One of the two later vehicles also displayed individual cylinder misfire fault codes.  Note that all of the plugs were burning well.  In other words, no heavy carbon, oil or fuel additive build-up that would have caused the misfires.  The plugs are just simply worn.  New spark plugs cured the misfires and improved engine response on all three.

Click image below for BMW and MINI spark plugs:

Click below for Metric Socket Set:

Check out the old vs. new spark plugs for these three vehicles, noting the fairly clean burning, but worn electrodes:

1995 M3, 145,000 miles:
Occasional misfires (bucking) under acceleration. No fault codes. Spark plugs had between 30,000 and 35,000 miles of use.

2012 MINI Cooper, 32,000 miles:
Quite apparent engine misfire and backfire noise through exhaust.  Cylinder #4 misfire fault code.  Spark plugs had 32,000 miles of use (original plugs).

2007 335i, 90,000 miles:
misfires under acceleration.  No fault codes.  Spark plugs had 31,000 miles of use (Walnut de-carbon blast performed 8,000 miles before).

Bavarian Autosport

BMW and MINI DIY Video, How to Install a Performance Tuning Module, aFe Scorcher, Dinantronics Sport, Burger JB Plus

Sep 29 16

Can you really add up to 60 Horsepower to your BMW for under $300 and 30 minutes of your time?

The short answer is yes, you sure can.  BMW’s newer turbocharged models make great power, right off the dealer’s showroom floor.  This applies to the four cylinder models just as well as the 6 and 8 cylinders.  With this noted, many BMW enthusiasts yearn for even more power and the BMW turbocharged 4 and 6-cylinder engines are certainly up to the task …. IF …. the engine management systems allow it.  The new generation of plug & play programmer/tuners from aFe Power, Burger Tuning and Dinan allow these engines to easily make “seat of the pants” power increases with great horsepower per dollar cost ratios and very little install time.  30 years ago, we would have to spend many times these amounts to achieve a 10% to 20% power gain.  We also would have spent dozens of hours to install the parts, all while working with comparatively dismal fuel economy.  The “Good Old Days of Hot-Rodding” are TODAY!

Click HERE for aFe, Burger and DINAN performance tuners

Let’s take a look at a few sample installations of the basic plug & play tuners from aFe, Burger and Dinan, on some BMW turbocharged models.

aFe Scorcher Power Module:

The aFe Power SCORCHER Module is designed to alter the pressure sensor signals to increase turbo boost to an optimum level throughout the entire RPM range. The result is a harmonious balance between power, throttle response and driveability. This module provides a hassle-free installation with no cutting, drilling or splicing and installation can typically be completed in around 30 minutes. Factory electronic accessories are not affected by installing the Scorcher module.  Available for most BMW turbo 4 & 6-cylinder models, including diesel and M3/4/5/6.

Burger Juice Box-Plus:

This plug-n-play performance tuner gives you huge power gains in just a few minutes. Choose the default gains or select maximum gains to be used with higher octane fuel.  Simply unplug two factory wires and insert the unit. That’s it — no cutting, no modifications, no tools. Plus, at the default setting, it will not trigger any codes. Available for most 6-cylinder BMW turbo models (except M & diesel) plus MINI.

Dinan DINANTRONICS Sport Performance Tuner:

DINANTRONICS Sport employs simple design and execution that allows for easy installation or removal in just minutes, producing results you’ll feel, and enjoy, from the first start. The DINANTRONICS Sport Tuner incorporates Bluetooth capabilities that allow user controlled adjustability and a live boost monitor to keep track of the action.  Available for many late model 4 & 6-cylinder BMWs and MINI.

Bavarian Autosport