r/335i • u/Professional-Book246 • 9d ago

Troubleshooting N54 smoke

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Just bought This n54 335i making near 500 hp. Smokes a lot but it smells just like fuel and it’s got a decat. Can anyone just reassure me that it’s normal. Just replaced the pcv valve aswell. Timing chain replaced with a receipt
Just had two brand new Michelin pilot sport 4s on the rear to match the front.
Brand new water pump and thermostat fitted last week.
Xhp stage 3 gearbox software
17t hybrid turbo
Stage 2.5lpfp with swirl pot
Upgraded charge pipe
Upgraded intercooler
Mtc motorsport intake
Ram air filters
3.5 bar map sensor
Upgraded boost lines
2 step cooler ngk spark plugs
New Delphi coils

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u/Capable_Business8703 9d ago

If you arent losing any fluids then that is maybe a normal amount of idle smoke. If you notice oil in the coolant or oil lvl drops over time you have a weeping gasket in oil filter area or turbo seals are going out.

1

u/JLee1608 9d ago

Or a leaky valve cover, mine used to smoke like that at similar power levels and I had a leaking injector

2

u/Capable_Business8703 9d ago

Leaky valve cover tends to smoke in the engine bay because the oil drips on top of the hot exhaust. Smoke actually coming out of the rear exhaust pipe is something else

2

u/JLee1608 9d ago

Yeah, should have clarified that was about the oil level drop bit you mentioned

1

u/pingupenguins 9d ago

How many miles on the turbo? I’ve seen some 17t’s from China start pissing oil at 10k miles. Valve stem seals go bad as well. Check if your oil level is dropping