My kids have been using our Fit over the last year. I rarely drive it. Recently, they’ve complained about a foul smell after startup (if sitting overnight or many hours). They say it goes away after about 5 minutes.

a little research says it could be related to catalytic converters failure or O2 sensor failure.

anyone else experience it? Car has 130,000kms. Issue is recent….wasn’t happening over the winter.

no codes thrown.

any ideas what it might be?

 

Cabin filter?

 

Possibly a loose spark plug. Outside chance it's fuel-related (broken line / pump / etc), but my money is on a loose plug.

 

Loose plug is what you want to check. To make sure it won't auto-eject. Remove bolts holding coil packs on, disconnect lead and slip coil pack off. With a plug wrench, see IF you can tighten. For a torque wrench that's 20lb ft, but seeing as many ppl don't have one, the important thing is that when you try to tighten it, it shouldn't easily get tighter. If it does, tighten it snug but not overly so. Do NOT try loosening the plugs first: if you loosen good ones with a good seat they may not seat as good after, so you should leave loosening to future you who is ready to put new ones in.
My 09 also don't smell great cold. Catalyst not warm yet. Not necessarily sign of failure. If the plugs are loose the problem wont go away when it's warm.

 

What kind of smell is it? I have never smelled a rotten egg or gasoline smell from my fit. I do however get a strong whiff of gym socks fairly often. This is from the HVAC.