Right values for Lambda

[Stevo]

Hello,

I'm meassuring on a 2-stoke scooter racing engine.
What should be the right values if the sensor is in open air? At the moment i get 1,8 lambda +-
When meassuring in exhaust i meassure 1,4 +- so it should be a bit lean. When i give more fuel it gives me 1,5 +- so what is going wrong?

Thank you!

[Christian_Bylund]

I'm meassuring on a 2-stoke scooter racing engine.
What should be the right values if the sensor is in open air? At the moment i get 1,8 lambda +-
When meassuring in exhaust i meassure 1,4 +- so it should be a bit lean. When i give more fuel it gives me 1,5 +- so what is going wrong?

Hi Stevo,

When measuring a clean sensor in air running at the correct temperature you should read an oxygen level above 20%. Even if you have the sensor in air and it has soot on it you might get a wrongful read. Try cleaning the sensor before you do an air read.

Inside an exhaust system when the engine is off, it will always pick up unburnt fuel and display lean lambda values.

Regarding your results, before commenting anything about it I would need to know how you perform your measurements. Are you measuring the same load at the same speed i.e working point?


Above is an example of how the lambda can differ between speeds at full load.

Make sure to keep an eye on temperatures when tuning 2-stroke!

Thank you.

[Stevo]

Thank you for the reply! As i found strange values, i ordered a new (real Bosch) sensor and now values are ok!
The other sensor was a replica i gues (also new) but quality was bad... So problem is solved! I have another question about a 0-5v output to connect it with our bench software so we can read the values... I open a new topic for it.

[Christian_Bylund]

Thank you for the reply! As i found strange values, i ordered a new (real Bosch) sensor and now values are ok!
The other sensor was a replica i gues (also new) but quality was bad... So problem is solved!

Great to hear you got it all up and running with the proper sensor!