Originally Posted by
Tu.114
With all else equal, including APU bleed pressure, the constant difference between ignition A and B is the position of the spark plugs.
IŽd look at the fuel injectors around those, possibly their individual flow rates.
Possible, or a fault in the Ign B circuit that is going undetected.
At any rate, this is something that needs to addressed - if the Ign B circuit is not working, you are effectively operating in MEL (ignitor failed) territory.