MINI Cooper S N14 Engine Misfire, Valve Timing Problems

Vehicle details:  2009 Mini Cooper S / N14 Engine / 66,xxx miles
6 speed manual transmission

TechnicianTyler Seawright (Master ASE Certified)

Initial condition:

  • check engine light on, hard starting condition and noisy engine.
  • Dealership diagnosed as valve timing problems:  Broken timing guides, bad VANOS pulley, and possible other repairs needed
  • Client came in looking for a second opinion

Diagnostic Process:

  • Verified with computer diagnostics:  misfire codes for all of the cylinders
  • Visual inspection of ignition components (spark plugs and coils) suggested they were ok
  • Tested basic engine datastream – found all parameter data with the engine off was correct, IE Coolant temp, Oil Temp, Battery voltage, Etc.
  • Monitored low side fuel pressure (the N14 is equipped with direct fuel injection system so it has 2 different fuel supply systems):  Low side fuel pressure system was good.
  • Attempted to start the vehicle and it started.
  • Ran running fuel pressure tests.  Fuel pressure within specs
  • When running the DME (engine computer) set a code “2B64 Intake manifold, unmetered air“.
  • Per MINI’s technical service bulletins, removed the valve cover to physically check the valve timing. With the camshaft alignment tools in
    place we found that the valve timing was correct.
  • Also inspected timing chains, guides, and tensioners:  all ok.
  • Further running tests found that the variable Valve timing( VANOS) degree measurements would not deviate from 36degrees.
  • Monitored the Duty Cycle command to the VANOS Solenoid actuator and noticed that the Duty Cycle was changing when being commanded from the DMEto change but the actual valve timing was not changing.
  • This lead us to a physical fault with the VANOS system that cannot truly be measure electrically by the DME.
    We removed the VANOS Solenoid and found that it was physically broken and was not able to supply engine oil to the VANOS gear and therefore would not change the valve timing.  (pictured below – broken solenoid in front / new (good) solenoid behind)

MINI_VariableValveTiming2 MINI_VariableValveTiming1

 

Conclusion:

This is a classic case of a physical inspection trumping what a diagnostic tree / computer diagnostic process suggests.  The dealership followed all MINI protocols and formal test procedures to conclude, consistently but incorrectly, that the problem was with the physical valve timing components.  Knowing that as a weak-spot in this engine design, MINI’s repair suggestions weren’t a bad thing for the vehicle but would not have fixed the client’s concerns.

In the end, we saved our client over $1300 of misdiagnosed repairs.  A big win!

Smart TIP:

This engine is not equipped with a oil level warning system to alert the driver that the engine oil is getting low. We Suggest that every other time you fill your car with gasoline, Check the engine oil.