Air fuel ratio of 4!

[robzrr]

My OBD Sensor reading (using a one from 'Torque') displays a value when the car is running and fully warmed up of around 3 to 4 :1 which is very low considering that the air fuel ratio of diesels should be around 14.7:1 to 15:1 . The 1.2tdi polo 6R is standard and has no smoke and runs ok apart from a little roughness between 1 and 2 thousand RPM and fuel consumption is around 50mpg which is a bit low for a bluemotion model. I suspect the Oxygen sensor is faulty...any ideas?

 

[JELLOWSUBMARINE]

14.7 @ sea level is gasoline engine mix sweat spot.

Diesel still baffles me as it seems so much more adaptable/flexible. I'm not sure if diesel can be held to many of the same standards as gasoline. Its a ability to make more power by cramming more fuel into the mix is certainly different than gasolines ability.

FWIW I also noticed the same 4:1 ratio at different times with my POLAR F.I.S. My thinking is it must be normal operation or the soot load would be very high.

 

[DivineChaos]

Something don't seem right here.

 

[robertsean350]

i have the same issue. a ratio of 3:1 would not result in combustion, yet the vehicle runs. we are missing a crucial piece of information. used the same tech on my rx8 no issues.