Burning rich.

[MadOx75]

So while cleaning my car, I noticed that there is a lot of carbon built up on my exhaust tips. I'm figuring that between the new better flowing exhaust and the K&N filter, the engine is burning rich. But shouldn't the ECU eventually adjust to the airflow and change the fuel mixture? Or maybe it has already and I just didn't notice the carbon until now? Should I just go out and yank the negative battery cable to reset the ECU just in case?

[ProudNissanFreak]

How long ago did you get the new parts?

[MadOx75]

How long ago did you get the new parts?

It's been a little over a month for the exhaust, and probably closer to two months for the K&N filter.

[philipa_240sx]

So while cleaning my car, I noticed that there is a lot of carbon built up on my exhaust tips. I'm figuring that between the new better flowing exhaust and the K&N filter, the engine is burning rich.

No, it's fine. Mine also has a considerable amount of carbon around the exhaust tip finisher. I have no mods. Carbon is a byproduct of combustion, it's normal to have some.

Nissan's have used mass airflow meter systems for years so they compensate quite well for engine modifications.

But shouldn't the ECU eventually adjust to the airflow and change the fuel mixture? Or maybe it has already and I just didn't notice the carbon until now? Should I just go out and yank the negative battery cable to reset the ECU just in case?

The ECU will adjust the fuel mixture over the long term (several weeks). Pulling the battery cable will do NOTHING to change this. That method went out with the old ECU's back in the 80's and 90's. The only way to reset the fuel trims nowadays is using the Nissan CONSULT III diagnostic tool.

[MadOx75]

That all makes sense, it just seemed to be a bit excessive. I guess its just that its more noticeable with stainless steel tips as opposed to the regular exhaust pipe. And good to know about not being able to do the ECU reset by yanking the battery... I havent needed to do it in so long I didnt realize.