2015 328i Engine misfire
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Member Posts: 1
Appreciate any advice on this. 2015 BMW 328i, 19,900 miles, leased from new. Brought into dealer for regular service, oil change, etc. 4 days later check engine light comes on and car starts running really rough. Had it towed to dealer. Dealer report:
TEST DROVE CAR, VERIFIED COMPLAINT. CHARGED BATTERY, PERFORMED
VEHICLE TEST, FOUND MISFIRE FAULTS STORED FOR CYLINDERS 1 AND 2.
PERFORMED TEST PLAN FOR FAULTS, PER TEST PLAN I CHECKED THE FUEL
PRESSURE SYSTEM FOR ANY LEAKS/DAMAGE, ALL WAS FINE. NEXT I REMOVED ALL
PLUGS AND COILS AND INSPECTED FOR ANY DEFECT/DAMAGE, ALL COILS AND
PLUGS LOOKED FINE. NEXT I PERFORMED FUNCTION TEST OF THE INJECTION AND
IGNITION SYSTEM, TEST FOUND THE INJECTORS FOR CYLINDERS 1 AND 2 FAULTY
[TEST PLAN RECOMMENDED REPLACING BOTH SPARK PLUGS ALSO]. REMOVED AND
REPLACED CYLINDERS 1 AND 2 INJECTORS AND SPARK PLUGS. PERFORMED
INJECTOR CALIBRATION AFTER REPAIR, CLEARED FAULTS AND TEST DROVE CAR,
C/E LIGHT CAME BACK ON. BROUGHT CAR INTO SHOP, CHARGED BATTERY,
PERFORMED VEHICLE TEST, FOUND MISFIRE STORED FOR CYLINDER 1. PERFORMED
TEST PLAN FOR FAULT, TEST PLAN PERFORMED SAME INJECTOR AND IGNITION
TEST. TEST PLAN RECOMMEND REPLACING THE INJECTOR FOR CYLINDER 1 AGAIN.
GOT FOREMAN AND TOLD HIM THE SITUATION, HE RECOMMEND REMOVING THE COIL
AND PLUG FROM CYLINDER 1 AND SWAPPING THEM TO DIFFERENT CYLINDERS.
SWAPPED COIL 1 WITH 3 AND PLUG 1 WITH 4. CLEARED FAULTS AND TEST DROVE
CAR, C/E LIGHT CAME BACK ON. CHECKED FAULTS AND FOUND THE MISFIRE FAULT
MOVED TO CYLINDER 3, FAULTY COIL. REMOVED AND REPLACED COIL. CLEARED
FAULTS AND TEST DROVE CAR, ALL WAS FINE.
Do they know what they are doing? All costs are covered by the dealer, so I'm not worried about costs, but I don't want the car to die unexpectedly on me in the future. The fact that the the technician fixed it 3 times with the check engine coming back on the first 2 times makes me nervous that the problem isn't really fixed and may re-occur.
Thanks in advance for any advice
TEST DROVE CAR, VERIFIED COMPLAINT. CHARGED BATTERY, PERFORMED
VEHICLE TEST, FOUND MISFIRE FAULTS STORED FOR CYLINDERS 1 AND 2.
PERFORMED TEST PLAN FOR FAULTS, PER TEST PLAN I CHECKED THE FUEL
PRESSURE SYSTEM FOR ANY LEAKS/DAMAGE, ALL WAS FINE. NEXT I REMOVED ALL
PLUGS AND COILS AND INSPECTED FOR ANY DEFECT/DAMAGE, ALL COILS AND
PLUGS LOOKED FINE. NEXT I PERFORMED FUNCTION TEST OF THE INJECTION AND
IGNITION SYSTEM, TEST FOUND THE INJECTORS FOR CYLINDERS 1 AND 2 FAULTY
[TEST PLAN RECOMMENDED REPLACING BOTH SPARK PLUGS ALSO]. REMOVED AND
REPLACED CYLINDERS 1 AND 2 INJECTORS AND SPARK PLUGS. PERFORMED
INJECTOR CALIBRATION AFTER REPAIR, CLEARED FAULTS AND TEST DROVE CAR,
C/E LIGHT CAME BACK ON. BROUGHT CAR INTO SHOP, CHARGED BATTERY,
PERFORMED VEHICLE TEST, FOUND MISFIRE STORED FOR CYLINDER 1. PERFORMED
TEST PLAN FOR FAULT, TEST PLAN PERFORMED SAME INJECTOR AND IGNITION
TEST. TEST PLAN RECOMMEND REPLACING THE INJECTOR FOR CYLINDER 1 AGAIN.
GOT FOREMAN AND TOLD HIM THE SITUATION, HE RECOMMEND REMOVING THE COIL
AND PLUG FROM CYLINDER 1 AND SWAPPING THEM TO DIFFERENT CYLINDERS.
SWAPPED COIL 1 WITH 3 AND PLUG 1 WITH 4. CLEARED FAULTS AND TEST DROVE
CAR, C/E LIGHT CAME BACK ON. CHECKED FAULTS AND FOUND THE MISFIRE FAULT
MOVED TO CYLINDER 3, FAULTY COIL. REMOVED AND REPLACED COIL. CLEARED
FAULTS AND TEST DROVE CAR, ALL WAS FINE.
Do they know what they are doing? All costs are covered by the dealer, so I'm not worried about costs, but I don't want the car to die unexpectedly on me in the future. The fact that the the technician fixed it 3 times with the check engine coming back on the first 2 times makes me nervous that the problem isn't really fixed and may re-occur.
Thanks in advance for any advice
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Got to love "factory training" because what the tech described is exactly what they are taught by the book. It takes time and experience, which is gained by both successes and failures to learn how to really diagnose vehicle problems. Even then there can often be more than one issue with a given vehicle and that can make testing beyond an obvious failure difficult if not impossible until the obvious issue is dealt with and taken out of the system. The following is a plausible explanation that would "fit the facts".
When an injector fails it can drive a cylinder either richer or leaner than the rest of the engine. A rich mixture could foul a spark plug, but a lean mixture can have an unexpected consequence. A lean air fuel ratio drives the spark demand voltage high. Spark demand voltage is the amount of voltage required to initiate the spark in the cylinder. An excessively high demand voltage can damage the ignition coil and/or cause the spark to jump through the boot at the bottom of the coil and then leak to ground. So the injector is the primary failure and the coil and spark plug suffer and possibly fail because of it.
That leads us to an interesting tendency in understanding the difference between "A Problem" and "The Problem". "The Problem" is always the last one discovered in a string of "A Problems".
Sometimes you have to fix the known problems to deal with the unknown problems.
Meaning, some of the obvious problems may have an underlying problem, but you have to correct the results to find that.
An example.
If a vehicle has a blown fuse. You know that the fuse is a result of the problem. Now you have to find the short that is causing the problem. But sometimes you have to put the fuse in, disconnect the things you know are in the system and watch it blow........or not blow the fuse.
BTW, I have breakers for testing.
I digress.