R56, N18, 2012 mini with manual transmission. Two known issues, minor coolant leak and cracked turbo intake line (just noticed both of these). Now, I've been getting a misfire when hitting the gas hard, it gets worse the higher the gear (basically more power makes it worse ). It starts with a deep rumble, loss of power, misfire on multiple cylinders and then limp mode. Restarting the car causes the entire thing to start over.

New intake is on its way. My question is this; would that crack in the intake cause this misfire? If the tube had a leak or came off completely would the computer detect the issue and throw it in limp? CEL only displays misfires on multiple cylinders.

 

Where is the crack? If the crack is anywhere between the mass air flow sensor and the throttle body you will have an issue for sure. You can also pull engine error codes, if it's a leak like I located, then you'll likely get a engine running too lean type of code.

 

Crack is right where it clamps to the turbo. Just got the part today but had a coolant line crumble in my hands so I have to wait for that to come in before I test it. I have a code reader, did get one for engine being stuck lean but I figured that was due to the decat since I am waiting for some money to tune it.

 

it has probably nothing to do with that crack. Slap some gaffer tape and call it a day. The knock you are having is super knock (lspi). Use api sn plus certified oil and change your driving habits to never pedal to the metal unless you are over 5k rpm. It has no real fix besides that. Cold air intake and a big intercooler with oil catch can or a good tune might ease it though.

 

I would cover that crack as recommended above. In the meantime, any codes to go off? Could be MAF sensor, coils, plugs, O2 sensor, breather hose, vacuum...

 

If there's a crack there, depends if the crack can be closed tight by the worm-gear clamps. If there's exposure due to the crack where air can be hissed out between the MAF and this joint, you'll definitely get an error code for it saying metered air volume is faulty or something of that sort.

Normally on naturally aspirated vehicle, you'll get a lean code because MAF senses less air going into the engine than actual, and as the ECU applies injector duty cycles and watch O2 sensor reading a lean burn out of range, When this happens, ECU uses a coarse open loop tune which will get the car minimally drivable for up to 2400-2500 rpms. Beyond that it gets coarser and coarser until it'll throw a bunch of check engine codes and limp mode.

On turbo cars, there's always a secondary check done by the MAP sensors, so chances are it'll just say something is wrong with the MAF meter reading when it detects a reading that doesn't make sense, but your MAP sensors should still be able to guide the DME to apply the correct injector duty cycles from a coarse adjustment, advance timing and VVT will be detered, that's probably why you get misfires on top end.

 

Actually turned out to be a connector on one of the coils wasn't connecting right. Not a huge fan of taping car parts together, tends to lead to further damage in the past. All's good now save for a minor coolant leak.