P2178 system too rich at idle bank1

[shinwin]

I have changed the maf and pcv but still the fault on computer and a black smoke came from the exhaust what should i do??

[Gunnark100]

I have changed the maf and pcv but still the fault on computer and a black smoke came from the exhaust what should i do??

Which engine?

Possible causes - Intake air leaks - Faulty front heated oxygen sensor - Ignition misfiring - Faulty fuel injectors - Incorrect fuel pressure - Faulty Mass Air Flow (MAF) sensor - Incorrect Positive Crankcase Ventilation (PCV) hose connection.

Tech notes Then engine is "too rich" when the O2 sensors detect more fuel than air during combustion. Leaking fuel injectors (stuck open or damage seals) and faulty Mass Air Flow (MAS) sensor are the most likely causes for this problem.

[shinwin]

The engine is 2.0tfsi the is no faults except the system too rich at idle how should i know which one of them causes the fault?

[shinwin]

And the code is p2188 am sorry about that

[van462]

Do you just have a code scanner, an OBD reader that connects to a smartphone or VCDS? To aid in giving you more steps to follow. These motors do experience a fairly high number of fuel injector failures but when an injector sticks it usually causes a misfire in the effected cylinder. You can pull your plugs and see if any are wet with fuel indicated a stuck injector. You will typically have white smoke and a strop gas smell in the exhaust.
Since its at idle only and no other signs then its possible the high pressure fuel pump is leaking gas into the crankcase. Remove the oil fill cap and see if there is a strong gas smell. If gas enters the crankcase either by washing down the cylinder walls or from the pump the gas laden vapors get sucked into the intake manifold by the PCV. The gas vapor can raise the fuel/air mix enough to read as rich. It occurs more at idle as engine vacuum is highest. Idle speed is also the least active for the ECU as the maps are pretty much the same as limp mode.

I supposed extremely gummed up intake valves could also trigger this as they may block enough air to cause a rich mix but I would think you would have very rough idle.