Reposting this here, initially posted in a different thread, but didn’t get many responses:
I recently learned that my M240i will need a new engine. The only modification is a Dinan Stage 1 tune and the car has less than 20k miles. I noticed that the engine was running rough after I exited the highway and slowed to a stop at a stop sign. Shortly thereafter I got a drivetrain malfunction and CEL. I carefully drove the car home (about a mile or two). It seemed like the car was just misfiring so I assumed it was a spark plug, an injector or some other ignition or fuel issue or maybe at worst a head gasket. I had it towed to the dealer and they later informed me that I need a new engine. I was shocked. Up until this point the only issue I had was a new crankshaft sensor, which I think was the subject of a recall (at the time this issue seemed significantly more serious and caused significant engine and drivetrain issues). The dealer was unable to say why I need a new engine at this time (seems like they are still looking into it), but one individual said they probably reached that conclusion after a compression test or finding metal in the oil.
I am certainly not a mechanic, but there seem to only be a few possibilities given the situation (i.e., car runs, seems to only be misfiring, and needs a new engine): (1) spun bearing, but I did not receive any oil pressure warning, (2) piston ring failure, (3) burned piston, and/or (4) a scored cylinder.
My dealer has submitted the claim to BMW, but no determination has been made yet. I also alerted Dinan in case BMW denies the warranty claim. Given the nature of the Dinan tune, it seems unlikely that it would cause any of the issues above, unless the knock sensor failed, but that would be a problem with or without the tune. Any similar experiences? Any thoughts or suggestions?
Based on the posts I have read, BMW seems to usually deny these types of warranty claims, but I’d be interested to know if anyone has had an issue that BMW covered despite the Dinan tune. It seems like Dinan is good about honoring their warranty, but any insight would be appreciated. My worst fear is that both BMW and Dinan deny warranty coverage or that it takes months to get the warranty issues figured out. This seems unlikely, but who knows... I’m not exactly on a lucky streak right now
