Whacked AFR/O2s
Whacked AFR/O2s wandering if anyone knows what is up with this commanded afr and the o2s? afr goes to 16, o2s flat line lean, then the afr goes to 13.6, o2s go rich then back to normal. i can give it 10-20% more throttle and the afr will come down to 14.6 or less and the o2s will start switching, but as soon as i back off the throttle its back to the 16 or 13.6 afr. it seems to happen after start-up (cold or warm) and a short normal drive of about 10 mins or so. then it happens. they all last about a minute or so. is this the evap? apologize for sqeezin the chart up, but wanted to get the whole cylce in.
it seems to happen within the first 15mins or so of driving and is completely random. here i am on a highway running 65-70mph when it kicks in. when coasting down the O2s will generally switch with the occasional flat line just for a second. when this happens i can tell without the scanner up and running. the truck becomes doggy because of being lean and when you increase the throttle it seems to struggle a little. it doesn't stumble or hesitate any, just has a "shimmy" to it, kind of like a rear wheel out of balance. but when it comes back to the normal afr all is fine.
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Maybe EGR kicking in?? Air Pump???
I dont know what would cause this exactly...but its worthlooking at if you still have those hooked up
what I dont know is why it commands 16:1 lik eyou are seeing there...
MAybe time to start looking at status bits to see whats up
I dont know what would cause this exactly...but its worthlooking at if you still have those hooked up
what I dont know is why it commands 16:1 lik eyou are seeing there...
MAybe time to start looking at status bits to see whats up
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Verdad Gallardo this is on an '04 silvy 5.3 don't have either. exactly, what is up with the commanded 16:1 afr. i have looked all through my tune and can't find anything that would command that afr. what is strange about it is, something is commanding 16:1, the o2s bottom out like it's lean, when if anything when commanded to 16:1 it should have been rich since it was coming off of 14.6. then approx 20secs or so it will command the 13.6 and the o2s top out like it rich, when it should have lean. this lasts approx the same 20-30secs and then its back to normal. it is pretty much the same routine everytime it does it, which is almost every start-up and drive cycle. there have been times that it hasn't, but i can't see anything that is happening that is different when it does do it. it has me seriously scratching my head.