Hi, this might be a stupid question but,,,,, I have just fitted an analogue Defi afr guage and the needle constantly flicks when driving between 14.7 which is normal and 16.5 which is leaner, 17.6 being lean. Just wondering if it is normal for the reading to fluctuate so much or if my oxygen sensor is nackered. The afr reading wire is connected to the ecu wiring via Blue plug 136, pin number 21, its white with silver stripes, on a my00.

Thanks in advance for any help.

Pete

 

my afr display dances around like a disco ball until under reasonable load, then it shoots up to rich

 

It will oscillate on light load as the ECU is in closed loop control, the signal should hunt around 14.7 on the gauge or anywhere between 0 and 0.9v voltage.
On high load the signal should be steady and rich, ie lower than 12 AFR and above 0.85V

Andy