what makes your run rich?
Staging Lane
Joined: Jan 2004
Posts: 65
Likes: 0
From: Annapolis, MD Fmrly Lansing, MI
My car has run rich from the get go, factory errs to the side of rich. Lots of things could cause it to run rich.
Headers allegedly increase the richness because you are moving the cats back. The 02 sensor sees more/cooler air and sees more 02, then it compensates with more fuel.
Bad EGR, PCV problems, bad 02 sensor, etc...all could ontribute or be the cause.
Is it REEAAAAAAAAAAL bad or just a little black on the tips???
Headers allegedly increase the richness because you are moving the cats back. The 02 sensor sees more/cooler air and sees more 02, then it compensates with more fuel.
Bad EGR, PCV problems, bad 02 sensor, etc...all could ontribute or be the cause.
Is it REEAAAAAAAAAAL bad or just a little black on the tips???
Commanded AFR from the factory is 12.5:1 at
WOT. This is richer than you need in most
cases.
Cold O2 sensors output a low (or no) voltage,
misinterpreted as lean mixture, causing the
PCM to compensate and make things too
rich. Headers lower the exhaust gas temp
quite a bit because the sensor is further from
the heat source and there's a lot more wall
area to shed heat before it gets there.
WOT. This is richer than you need in most
cases.
Cold O2 sensors output a low (or no) voltage,
misinterpreted as lean mixture, causing the
PCM to compensate and make things too
rich. Headers lower the exhaust gas temp
quite a bit because the sensor is further from
the heat source and there's a lot more wall
area to shed heat before it gets there.
