AFR Variations between left and right banks

[MagicMike]

Hi All,

I recently installed a second AEM wideband, so I now have 1 in each bank. Driving around a bit on the weekend, I noticed quite large variations between the 2, both at idle, and under very very light throttle.

Drivers side goes lean at idle (16-18:1) where as the pass side is 13/14:1. At slight throttle, drivers side goes rich at 11:1 and pass side is about 14/15:1.

All other conditions see both gauges reading the same. WOT, cruise, part boost etc.

I haven't tried swapping the sensors over to see if the reading swap banks or not (seeing if a sensor is bad).

Any other thoughts?

[Matt]

Assuming a Z32 here... try swapping sensors

Also watch your injection time and see if they are the same when looking at them in Nistune. If so then the other thing to check is your injector flow rates. One might be running leaner than the rest...

[Eric]

If this is on a Z32, then most likely this is caused by the IACV (idle air control valve)... it's feed from the LH intake and can cause imbalanced AFR's at idle/low throttle conditions.

if you watch AFR vs. IACV opening percentage, you may be able to see if this is the cause of the imbalanced AFR's on your car.

[MagicMike]

Thanks gents, I am not expecting the injectors to be flowing differently as they were recently flowed and balanced.

IACV I have suspected a bit dicky so something to def check.