2017 Honda Civic 1.5T - P0172 System Too Rich - Gasoline smell in oil

Question

I have a 2017 Honda Civic with the 1.5 Turbo. Lately, it's been running a bit rough and the MPG has dropped from 35 to about 26. The P0172 code popped up for a rich condition. When I checked my oil, the level was actually *higher* than the full mark and it smells like a gas can.

I'm worried about the engine longevity if there is gas in the oil. I do a lot of short trips in cold weather, which I heard might be related, but this seems excessive.

OvernightOscar · Accepted Answer

✅ Confirmed fix: This is the well-documented fuel dilution issue on the L15B7 engines. The fix involved a dealership software update to the PCM that modifies the fuel injection timing to help the engine heat up faster, and in some cases, a replacement of the original AC control unit to prioritize engine heat. Since the update and changing my driving habits to allow for longer warm-ups, the oil level has remained stable.

DIY_Denise · Answer

You might have a leaking High Pressure Fuel Pump (HPFP). The seal on the plunger can fail, allowing pressurized fuel to leak directly into the valve train area. If the software update doesn't work, that's the mechanical part you need to inspect.

2017 Honda Civic 1.5T - P0172 System Too Rich - Gasoline smell in oil

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