Everything stinks on cold startup

[Mike W.]

No, I didn't put it in Tech as I don't think it's a vehicle issue as multiple vehicles do the same thing, rather I suspect it's gas or something.

Anyway, the '98 E36, the 02 E39, an 03 Nissan and an 07 Nissan. All running well, no check engine etc. On cold start they all stink. All modern 4 valve, variable valve timing etc. Start 'em up and they stink. I can't quite place the aroma, it's not a rich cold start like days of old, but it isn't good. Nothing is going to happen on my end since it's an irritation not a real problem, except if one happens to be pointed into the garage and even then it doesn't set off the smoke detector or CO monitor inside the house. I suspect it's the bizarre blend of what they now call gasoline, but I don't know. Anyone know what's going on?

And for the record, warm starts, running when hot or warm, no problem. Maybe not quite an air purifier, but I don't notice anything.

[turbodan]

I think I know the smell. Cold start through a catalytic converter produces a certain smell. Kind of like soap but not really.

[Panici]

They'll try to light off the cat converter on a cold start. This usually means running rich and at a high idle for a while.
Even newer cars will mess with valve timing to try to get more fresh air into the cat for the same reason.


You could modify the tune or exhaust system, but probably shouldn't do either for a street legal vehicle if you want to stay in compliance.

What type of fuel do you have in your area? Ethanol content?

[Mike W.]

What type of fuel do you have in your area? Ethanol content?

Oh gawd, yes on ethanol, 10% year round and it's who knows what kind of a crazy soup they've got blended with other stuff in it. The stuff doesn't even evaporate any more, you spill a little and it just sits there. California gas is "special" They make no bones about it, they want it leaner at cold start than it was designed to be, which is why the ethanol. 4% O2 IIRC in the overall gas blend.