Hi Guys, anyone come across this before?
Audi RS4 2018
Bank 1 sensor has been replaced. Showing as running too lean and too rich at the same time
Too Lean and Too Rich
Re: Too Lean and Too Rich
Is this the long or short term trim?
Have you got any live data plots?
Any idea how frequently it switches from rich to lean?
Was the lamda sensor a reputable brand? I assume you mean you changed the lamda / O2 sensor.
Thinking out loud, if you have swapped the sensor, what if there is an intermittent open or short circuit in the loom.
i.e. the loom goes open circuit the ECU thinks the engine is running lean and so adds more fuel, the open circuit then makes momentarily, the ECU gets the right reading which is now way too rich, so it backs off the fuel.
And repeat!
Possible causes for running too rich (from Ross-Tech):
Fuel system
Excessive fuel pressure
Leaking or contaminated fuel injectors
Leaking fuel pressure regulator
Low fuel pressure or running out of fuel
Vapor recovery system
Air leaks after the MAF
Vacuum leaks
Improper seated engine oil dipstick
Stuck EGR valve
Oil overfill
Cam timing
Cylinder compression
Exhaust leaks before or near HO2Ss.
Have you got any live data plots?
Any idea how frequently it switches from rich to lean?
Was the lamda sensor a reputable brand? I assume you mean you changed the lamda / O2 sensor.
Thinking out loud, if you have swapped the sensor, what if there is an intermittent open or short circuit in the loom.
i.e. the loom goes open circuit the ECU thinks the engine is running lean and so adds more fuel, the open circuit then makes momentarily, the ECU gets the right reading which is now way too rich, so it backs off the fuel.
And repeat!
Possible causes for running too rich (from Ross-Tech):
Fuel system
Excessive fuel pressure
Leaking or contaminated fuel injectors
Leaking fuel pressure regulator
Low fuel pressure or running out of fuel
Vapor recovery system
Air leaks after the MAF
Vacuum leaks
Improper seated engine oil dipstick
Stuck EGR valve
Oil overfill
Cam timing
Cylinder compression
Exhaust leaks before or near HO2Ss.
Re: Too Lean and Too Rich
Hi Josh, thanks for your reply,
Its currently with Audi Bolton and they cant seem to get to the bottom of it. The lambda sensor was direct replacement from tps so genuine part fitted.
Ive also had the pcv valve and spark plugs replaced recently Audi are claiming they are waiting for further instructions from Germany. They claimed the fault had been rectified, drove 20 miles and the engine management light came on and OBD reader threw up exactly the same codes.
Its currently with Audi Bolton and they cant seem to get to the bottom of it. The lambda sensor was direct replacement from tps so genuine part fitted.
Ive also had the pcv valve and spark plugs replaced recently Audi are claiming they are waiting for further instructions from Germany. They claimed the fault had been rectified, drove 20 miles and the engine management light came on and OBD reader threw up exactly the same codes.
Re: Too Lean and Too Rich
That sounds like Audi, plugs and air filter are usually changed every 40,000 miles.
Anything away from a normal fault and there lost.
I hope they manage to get it sorted.
It would be useful if you can post what they find once its done, it might help someone else in the future.
Anything away from a normal fault and there lost.
I hope they manage to get it sorted.
It would be useful if you can post what they find once its done, it might help someone else in the future.
Re: Too Lean and Too Rich
Just an update on the too lean too rich matter. Audi established it as a faulty catalytic converter. Had an RAC warranty which covered most of the bill but car was in Audi for at least 2 months
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