Is it normal for the sensors mv to be that far apart at idle. I have attached a log for reference
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Is it normal for the sensors mv to be that far apart at idle. I have attached a log for reference
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Is that the log you intended...or am I having issues on my end reading that - there is not enough frames/time to tell.
My vehicle, which I have just put new headers on, takes about 2.5-3.5 seconds (5-8 fuel trim notches) to swing at idle and still 1.1 seconds at 2000rpm - their response is also squiggly as shit between 600-1800rpm suggesting their location is not quite ideal.
Basically unless at WOT the b1s1 will be more than 500mv lower than b2s1 they are only close when at WOT but at idle they are very far apart.
a wavering pulse is normal. you are seeing one follow the other, the 500 or so MV slip is normal, they soon catch up and jump back an forth
ok so at dead idle having a 500mv difference is normal until i give it throttle.Quote:
Originally Posted by scites
You're completely misunderstanding how narrowband O2 sensors work.
During normal operation (non WOT) they will always cycle from ~750mV to ~150mV. Both banks will do this. This is completely normal and standard for closed loop. They may not cycle exactly in sync. One may be at 750mv while the other is at 150mv, then they could swap. Doesn't matter.. the point is you should see both banks cycling.
The cycling happens at different speeds depending on airflow. Higher airflow, generally, means they will cycle faster.
Narrowbands are only useful in NON WOT conditions. You need a wideband to get any useful information of AFR at WOT.
During WOT they should read similar, but you can't use them for tuning at WOT. That is not what they are designed to do.
Your log is so short I can't tell if anything odd is going on or not, but I don't see anything horrible at first glance. (aside from -14 fuel trims)
Hi c_low29.
I have attached 12 mins of idling and free-revving to show how the forward banks (Bank n Sensor 1) switch their lean/rich readings and how that directly affects their respective Short Term Fuel Trims (STFT Bank n).
The two banks are independent of one another - they may appear in synch at times, but as their STFTs may vary just a few milliseconds, which alters the fuelling to which the sensor responds (assuming you are indeed running closed-loop ?)
The relationship should be seen in the default Chart display - just zoom the thing out as far as you can.
If you jump to the 9 minute mark you'll see I increase the revs ever so slowly and sensors cycle spasmodically - which suggests I have them in a poor location and they may be influenced by two tubes. I may need to correct this as the car does spend a lot of time at these revs. Once it passes 2000rpm, the sensors cycle faster as there are larger changes to the STFT gain.
I hope this helps