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AFR Lambda reading during overrun fuel cut


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I am somewhat confused about my AFR reading. I run 2 Link CAN Lambda sensors on Bank 1 and Bank 2 of my 2GRFE engine. I have set the overrun fuel cut as ON.

If my understanding is correct, all six injectors should shut off when the overrun fuel cut features are active, thus giving a lean reading of 10.1 Lambda.

However, I realize that is not the situation here:


As the picture I snip from my logging parameter shows, the maximum reading of a Lambda 2 that it could reach when the overrun fuel cut is active is only 7.238 lambda. How can this be possible? Should it be the same reading as Lambda 1? 

I have attached my logging file and my base map to the Google link here. FYI, both CAN Lambda are powered by my PMU16 with a dedicated Auxiliary output. The sensors are less than 12 months old. Is there anything that I have been doing wrong?


Please advise



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Hi anyone,

Any idea what could cause for this issue? I hope is not the Lambda sensor issue as i just change it less that 10 months. I also have wired in capacitor according to the manual that suggest as an option.

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I suspect the sensor on lambda 2 is faulty, you have an error 24 from around the 4min mark in your log and error 17 from around the 9min mark.  Both of these errors relate to pump current which means the controller is trying to pump more oxygen ions into the measurement cell but it is not seeing the response in the chamber it expects.  It could be from contamination or "sensor poisoning"

A good test to confirm would be to swap the sensors side to side to see if the unexpected behaviour moves to the other side.  

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