Running Rich

[faqncb7]

So like the title says my 92 ex is running rich. When the car is idling its smells really rich I changed my plugs and they were a whitish brown color. Could it be the o2 sensor or maybe the coolant temp switch? I also get crappy gas mileage. Just wondering if anybody else had this problem?

[ON_N20]

Whitish-brown color is generally the color you want. If they were sooty and black, then I would assume you are running rich.

When does it smell rich? All the time or just at start up? At start up your engine will burn richer, a cold engine requires more fuel.

If your coolant temp sensor, or even air intake sensor are not working right (reading cold), they could trigger the ECM to provide more fuel making it run rich.

What modifications to your engine do you have? Hopefully your not running one of those silly "power chips" that are really just a cheap resistor inline with the air temp sensor wiring .

Also yes the O2 sensor could affect mileage and air fuel ratio's. The oxygen sensor is there as a reference to determine rich or lean conditions, so if its not working properly it may force the actual air fuel ratio's more rich than what is actually preffered.

Do you have a working EGR valve, or is it blocked off or working improperly?