The Scanmaster G shows the O2 readings moving real slow. I was told if it is not moving around quickly from reading to reading that it was bad. I notice today while the car was idling it just sat on 45 for like 10sec then went to like 80 and back down again. I am total Newbie on GN's but learning something new every day.
O2 going bad?
- Thread starter Opie
- Start date
SCOOBY DOO
BASED CANADIAN PATRIOT!!
- Joined
- Feb 18, 2007
When you notice the 02's and CC's starting to move slower the 02 is on its way out. Replace it with a Denso.
Boostrules
Member
- Joined
- Mar 16, 2013
How slow is the cutoff for replacement? For instance if the CC's jump 40 or less each time should it then be replaced?
SCOOBY DOO
BASED CANADIAN PATRIOT!!
- Joined
- Feb 18, 2007
As soon an you see the CC's and 02's slow down in the least from the norm...drop a new Denso 02 sensor in.
Boostrules
Member
- Joined
- Mar 16, 2013
Since I first installed my Scanmaster G the climb in CC counts is between 70 per frame when cold to about 40 when up to temp. It has remained steady thru out. Car runs well but wondering if I should see a bigger difference per display. Don't want to change O2 sensor unless it needs to be done. Is the norm 10 to 20 counts per frame & if so then leave the O2 sensor alone?
SCOOBY DOO
BASED CANADIAN PATRIOT!!
- Joined
- Feb 18, 2007
You've already noticed your 02 numbers slowing down...which means it's going bad. When it craps out it'll leave you stranded. Been there...done that.
Boostrules
Member
- Joined
- Mar 16, 2013
No, it goes all the way to 255 then comes back around thru 0 at about 40 counts per frame. I guess to be safe I'll just replace the O2 with a new Denso unit. Thanks to all for your feedback.
- Joined
- Feb 18, 2006
Guys,
Cross counts are "counting" every time the o2 "crosses" from rich to lean and lean to rich.
Cross counts won't move until the ECM goes into closed loop.
Normally when starting a GN cold, the o2 millivolts are in the 400's. It will climb as the sensor warms up into the 700's.
The o2 millivolts will start to swing once the ECM goes into closed loop.
Cross counts are "counting" every time the o2 "crosses" from rich to lean and lean to rich.
Cross counts won't move until the ECM goes into closed loop.
Normally when starting a GN cold, the o2 millivolts are in the 400's. It will climb as the sensor warms up into the 700's.
The o2 millivolts will start to swing once the ECM goes into closed loop.
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