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IDLE Lambda Offset Settings


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 I am scratching my head (bald head!).  I have notice whilst in IDLE DRIVE (not sure if it does it IDLE PARK - will check this tomorrow) I see commanded lambda pushed out to 0.9 and then the fuel trims follow.  The PCM hold 0.9Lambda quite well at the idle. 



ECT = 94Deg

Fuel Base Table is "1"

Fuel Cold Base Table is 0.85

Use Fuel Base above 71Deg so it should be 1.

I just picked this up this arvo and have gone through days of logs to find the same.  Would anyone in the forum please point me in the right direction please.


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1.0 * 1 -1.133 = 0.867

You have 13% short term fuel trims so it makes sense to me. This is normal as the narrowband is trying to induce a rich lean lambda oscillation to keep the catalytic converter in the efficiency region.

Can you log your o2 volts against it? It is probably reading lean hence the short term trim commanding a rich afr to attempt to get it to swing.

Short term trims are not very useful to log as they will always oscillate. Just look at the long term trims and your actual wideband reading. The fact you have -0.8% LTFT means you've got it dialed in well imo.

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