Some crazy O2 switching problems under part throttle.
Thread Starter
Joined: Nov 2001
Posts: 10,813
Likes: 15
From: Doylestown PA
Some crazy O2 switching problems under part throttle. This weekend I had a chance to have a friend do some data logging and drivability tuning for my car. We noticed that at part throttle 10-40% in lower rpm ranges (1600-3800), when I would roll into the throttle my O2's would start switching like crazy till I hit 50% or greater throttle or went above a certain rpm, and they would then stabilize and smooth out.
I will try and post a snapshot later, but think of it like a richter scale twitching during an earthquake. Both O2's were doing this, so I don't think it's a isolated issue to one side or the other. They are both relatively new (<10,000 miles) and they switch normally at steady throttle or at WOT, it's just at part throttle.
So has anyone ever seen something like this? Once again I will post more info when I get the tables at a later point in time.
Thanks guys.
I will try and post a snapshot later, but think of it like a richter scale twitching during an earthquake. Both O2's were doing this, so I don't think it's a isolated issue to one side or the other. They are both relatively new (<10,000 miles) and they switch normally at steady throttle or at WOT, it's just at part throttle.
So has anyone ever seen something like this? Once again I will post more info when I get the tables at a later point in time.
Thanks guys.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
They're supposed to switch as the PCM homes in on stoichiometric AFR (is this what you're seeing, or is it something else...?);
at WOT or in open loop they will go steady (and they stop switching) at some voltage giving you a [very, very] rough estimate of AFR;
post some pics, let us see.
at WOT or in open loop they will go steady (and they stop switching) at some voltage giving you a [very, very] rough estimate of AFR;
post some pics, let us see.
yeh, as far as i know thats what they are supposed to do.. based on MAP and TP position(also load) they will go from stoich to your PE AFR which should be relatively smooth
