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[PLANETNZ]

Ive changed a fair of few maintence parts etc including exhaust past few months, out of interest would would a O2 reset do??  Cheers

[Marks DTM Calib]

No such thing, you can reset the learnt values  but they will adjust automatically over times.....assuming they need to.

[PLANETNZ]

No such thing, you can reset the learnt values  but they will adjust automatically over times.....assuming they need to.

  yea thats what I ment I was woundering that because of all the recent changes, exhaust, maintenance etc that these  "old" values wernt suitable now and restting would work better with all the new bits!?  (Christ im getting lost myself now!:)

[Marks DTM Calib]

Resetting is the ideal if you have the means to do it (check them first though as they may be fine).

But with running over a few tens of miles they will adjust themselves anyway.

[PLANETNZ]

so the operating perameters are "fuzzy logic" rather than a pre-set factory?

[Marks DTM Calib]

so the operating perameters are "fuzzy logic" rather than a pre-set factory?

Not fuzzy logic in the true sense.

There are short term and long term trims, each effectively have a different time constant. The ECU looks at the mass of air and the dx/dt of the throttle (e.g. speed of opening) then injects a set of amount of fuel based on the fuel map. The O2 reading is then looked at to see 'how correct' it was (this is averaged over time as O2 sensors are not that fast). The ECU can then learn a correction value which is applied to the fueling.

[Diamond Black Geezer]

Ah, so if for instance, you'd run without a MAF, or perhaps an air leak causing a wonky air-fuel mixture etc, this could cause the engine to be running 'rough' etc?

[TheBoy]

There are short term and long term trims, each effectively have a different time constant

On the ODBII ones. 2.5 and 3.0 and early 2.0 have a slightly different setup (Idle and partial load).

To clear the trims on petrol Omegas, put on an artificial fault to store a code, then use a code reader capable of clearing fault codes.

[PLANETNZ]

Ok, i took the plunge and reset the O2 values. The one thing I did notice that the tech2 asked for engine running and as soon as i hi conform the idle cleaned up, didnt even notice it was off!?
Initial response is that the car seems to drive.."cleaner" for want of a better word, more responsive and the fuel use off the computer SEEMS to be much better, now showing 9.2 ltr per 100km rather than 6.9. not in any way scientific!
one thing that has now shown as a code is  #73 MAF (its genuine Bosch and reasonably new)  arewe talking Newtons 3rd law or has something else now happened??  cheers

[duke101]

now showing 9.2 ltr per 100km rather than 6.9. not in any way scientific!

Unless I am reading this wrong your fuel consumption is now worse. Its taking 9.2lt to do 100km instead of the 6.9lt it used previously.

[TheBoy]

How many miles has it done since the reset?  It'll take a few miles for the engine to find its correct trim levels, esp if one of the related sensors is misreading.

[PLANETNZ]

now showing 9.2 ltr per 100km rather than 6.9. not in any way scientific!

Unless I am reading this wrong your fuel consumption is now worse. Its taking 9.2lt to do 100km instead of the 6.9lt it used previously.

Ahh yea Duh on my part, meant KM per 100km!  I wish the omega trip computer would rear out the other way!

To update after a few 100km its settled down to about 8.3 (Ltr for 100!) The idle is a bit more "lumpy" or sounds / feels it but it definitely has a bit more Omph
Nothing actually scientific but interesting