[Karimkix]

Hello, I recently bought an E90 320i (N46B20), but I'm experiencing a problem. My car starts misfiring on cylinder 2 after driving for about 15 minutes. The misfire doesn't always happen but occurs most of the time. The car has a crackle tune. it also catalytic converters are empty.

I've already replaced several components, including:

Fuel pump and filter

Fuel injectors

Spark plugs

Ignition coils


Despite these replacements, the issue persists. A diagnostic scan revealed the following:

Errors related to all four oxygen sensors

Misfires on cylinder 2 (and occasionally on cylinder 1)

MAP sensor (though I don’t believe this is the cause of the problem)


Additionally, the car is consumes a lot of fuel, reaching as high as 18 liters/100 km (or 13 miles per US gallon).

[Karimkix]

Bump

[ptpending]

check if you have good ground wire between engine and car body
because since someone did euro2 (decat) conversion for this car, only he know what was done
the key idea for basic euro4 car is that HFM is not used if all lambdas in place(HFM not installed from factory, only temp sensor put in same assembly on intake), the adjustment done by them
if you have no lambdas, then you need to put HFM to do correct fuel mixture corrections, and also be sure that correct firmware for all of that is in DME
everything else is not possible to diagnose remotely
the first diagnostics rule in such situation (custom tuning) is put everything back as it was from factory