MoTeC Global Forum

hi guys,

has anyone experience with free air calibration for the lambda sensor? how accurate is the calibration?

i have a bosch wide band sensor. i tried free air calibration but the value is much higher, than
a tuner calibrated some years ago.

has the engine to be started when i calibrate or should i only turn on ignition?

the second question i have: why does lambdy reading only work when the engine is started? if i turn on ignition
i get the error C-6. after i cranked the engine and after warm-up delay i get the lambda reading.

regards

The free air calibration is what you should use if hte sensor is old, you should really do it regularly anyway. As the sensor ages it will change slightly.

Are you sure the original tuner set it properly?

The C-6 is because the sensor will be set up for slow heat which means it only runs when the engine is running and the timer has elapsed. The timer depends on engine temperature.

Do you have to completely remove the sensor from the exhaust system to do the air calibration or can you leave it fitted in the exhaust without the engine running of course.
would it be more accurate if removed & calibrated in fresh air?

you need to remove it from the exhaust pipe completely, and turn the sensor onto fast heat.

Once you have enabled fast heat, wait for the sentor to heat up and start reading.

Eventually, when it has stared, and is no longer showing a C-1 to c-6 error, instead showing a reading, go to the air calibrate screen, and highlight the sensor to calibrate.

you will see the cal number bounce around, and eventually stabalise, moving around only about 1 number.

press enter on that value to lock it in, then turn the sensor back to slow heat (to avoid a flat battery from the sensor heaters when the engine isnt running)

-Jamie

Does the air cal screen not force it to heat anyway, even if not in fast heat mode?

Make sure you are in clean air and not any wind, a light breeze across the sensor will affect how long it takes to air calibrate it. Should not matter is you are in fast or normal heat.

Found a strange issue with version 3.51 software when doing the air calibration today.

I have M800 with PLM connected via Can.

when i was doing the free air calibration (Sensor removed) I noticed if i closed that window & went to the Lambda table then back to the air calibration the ECU would show the last site number from the lambda table on the air calibration setting & i could calibrate to that number! ie .90 would become 90 on the air calibration setting??

I only noticed this because it was such a large difference from the last number recorded i went in an out several times & found i could also get the same result with the fuel table except it removed the decimal point ie 45.0 to 450.

I'm now unsure to trust the actual air calibration number i have. I was expecting it to change whilst the sensor was warming up but it never did.
Can anyone shed any light on this.

anyone?

Were you trying to do the air calibration in the ECU or PLM software? Its not very clear from your post.

If the lambda sensor is connected to the PLM then you need to carry out the air calibration of the sensor in the PLM.

fyi 3.51 software is an old release.

Ok, I was in ECU manager. Did not know that. So the Can connection is only a one way thing.

Bit of a pain having to pull my console out to hook up the serial cable & power up my Old Laptop with serial port I bought from Noah.

Thanks for the info.