What causes not matching duty cycle in SD tune ?

[wesam]

today while i looking at one of my logs i noticed that the duty cycle in some areas is different between bank 1 and 2 by +-1 what could cause this ?
my car is OLSD tuned and the O2 sensors are unplugged and no MAF also
and I'm not commanding stoich in B3647

[mr.prick]

How big is the difference?

[wesam]

2% some times

[mr.prick]

Nothing to worry about IMO.

[wesam]

Nothing to worry about IMO.
So is it normal to happen ?

[mr.prick]

I've seen it before.
Fuel trims could still be in effect. :nixweisss:
They should be reset even in open loop.

[wesam]

How could i reset them ?

[joecar]

In scantool: goto DVT tab, select your PCM, click Activate, goto Learning subtab, click Fuel Reset.

[wesam]

Thanks Joe
how often should i reset it ?

[swingtan]

If you have disabled fuel trims, then you should only need to rest them the once. I know that with the E38, the LTFT's are still applied even when running in OL. This is because the LTFT's are applied during PE mode, which the takes as OL mode. Disabling CL mode, only prevents the application of STFT's and the continued learning of LTFT's, already learned LTFT data may not be cleared out unless it is forced. This then results in the LTFT data being applied even though the rest of the trims are disabled. To prove this, log the LTFT's to see if they are doing anything.

Simon

[wesam]

Monitored LTFT and it shown as zeros all the time
tried to reset the trims from DVT but an error msg is appear that they could not be reset