marcink
December 14th, 2005, 05:11 AM
Hi,
When I switched to SD for AutoVE tuning I started to observe a strange AFR behaviour after engine startup. Alhough my VE table is within 1% now, after starting the car (cold or hot) the wideband sensor shows about 2 points lean (14.5 versus 12:5 commanded or almost 17 versus 14:7 commanded). This difference gradualy decreases in time and it takes 3 to 5 minutes.
First I thought that it is a "feature" of my wideband sensor - following battery voltage (which is higher after startup - like 15V - and then decreases to 14V) or needing warm up. But that is not the case because when I switched back to non SD tune everything was fine. The actual AFR shown was even richer than commanded AFR - but the difference between them stayed the same while in open loop and they became identical after entering closed loop.
So what am I missing? I cannot just increase these 2 cells in the Main VE table because if I get actual AFR = commanded AFR at startup it will become rich after 3-5 minutes.
So are there any other tables to control that behavior?
And this has nothing to do with the after-start enrichment which is operational for the first 10-20 seconds.
Thanks,
MarcinK
When I switched to SD for AutoVE tuning I started to observe a strange AFR behaviour after engine startup. Alhough my VE table is within 1% now, after starting the car (cold or hot) the wideband sensor shows about 2 points lean (14.5 versus 12:5 commanded or almost 17 versus 14:7 commanded). This difference gradualy decreases in time and it takes 3 to 5 minutes.
First I thought that it is a "feature" of my wideband sensor - following battery voltage (which is higher after startup - like 15V - and then decreases to 14V) or needing warm up. But that is not the case because when I switched back to non SD tune everything was fine. The actual AFR shown was even richer than commanded AFR - but the difference between them stayed the same while in open loop and they became identical after entering closed loop.
So what am I missing? I cannot just increase these 2 cells in the Main VE table because if I get actual AFR = commanded AFR at startup it will become rich after 3-5 minutes.
So are there any other tables to control that behavior?
And this has nothing to do with the after-start enrichment which is operational for the first 10-20 seconds.
Thanks,
MarcinK