socallmechris

my secondary o2 is bad, would this change my fuel economy? ive been getting like 25mpg out of a d16y8. i used to get 35-40ish depending on how i drove.

97Ej6mike

No, the secondary 02 is strictly for emissions.

Gas milage is dependant upon things like primary 02, map sensor, EVAP system, fuel system, motor efficiency (proper ignition, timing, spark, ect) and most of all... Driving habits.

thesmogman

The secondary O2 sensor is just for cat efficiency only.

Now if the Check Engine Light is on it will effect your mileage. When the CEL is on the ECU run's off a standard set of settings to save the other emissions components. It run's rich to do this and running rich will effect your mileage.

97Ej6mike

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by thesmogman &raquo;</TD></TR><TR><TD CLASS="quote">The secondary O2 sensor is just for cat efficiency only.

Now if the Check Engine Light is on it will effect your mileage. When the CEL is on the ECU run's off a standard set of settings to save the other emissions components. It run's rich to do this and running rich will effect your mileage.

</TD></TR></TABLE>

You sure about that, that may be limp mode your thinking of. Ive driven 8 months with and now 7 months without a CEL, and ive maintained a pretty steady D.D rate of about ~30-34 mpg.

thesmogman

Well that is the way it is suppose to work Are you sure? Just kidding

I am now wondering if there is some codes that will and some won't.

What was your code? was it for the cat efficiency like the OP?
I'm just trying to understand why!

socallmechris

the CEL is on, thats how i know its bad. and that would put my increased fuel consumption into perspective.

looks like ill be replacing that soon. thanks guys!