Fuel ratio

DANSULLS

MEMBER
2007 GMC ACADIA
3.6L
6 CYL
4WD
AUTOMATIC
134,660 MILES

Fuel ratio is at 1 to 1.
Had engine replaced 300 miles ago replaced all o2 sensors mass airflow sensor and replaced bank 2 catalytic converter. It runs poorly. On my scanner it's showing air fuel ratio in the red at 1 to 1 ratio. The problem didn't occur until the engine was replaced. It was a crate engine from the dealer.

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good evening,

The fuel ratio goal is 14.7 to 1. The job of the O2 sensor is to maintain that number. If the sensor is not working, that would explain the reading.

https://www.2carpros.com/articles/how-an-oxygen-sensor-works

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

Are there any codes set?

I am concerned about whether your scan tool is reading correctly. Can you tell me the voltages of the 2 upstream sensors?

Roy

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