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O2s wave form

pinkic81

Elite Explorer
Joined
September 7, 2014
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Year, Model & Trim Level
2003, sport trac
Hello, I'm the owner of the Ford Explorer Sportrac 2003, V6, 4.0L and 200,000miles on the way:burnout:, and I bought a ODBII scanner and I read the O2s sensors and the wave forms you can look in the picture.

I was reading it's a bad wave form, so I started to looking for a bad connection, and i didn't get nothing , so I decide to change all 3 new o2s sensors, and the same fave form, found a bad spark plug cable, i changed it and still the same wave form.

So I'm triying to find a solutions to get a better wave form in the B1S2, any Ideas????:dunno:

PD: No CEL ON
Thanks in advance.
 

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I see nothing wrong with these readings. In short and over-simplified, if you were to look at these voltage readings in a shorter time base/frame rate (imagine stretchering that red line(B1S1) until it resembles a smooth wave) that green line (B1S2) would essentially be a straight line. Like it should be. I hope that makes sense. It's very difficult to explain this with-out writing a book.
Not enough info here to diagnose anything.(your other o2 sensor and STFT's and LTFT's would help) But, assuming this is at idle and engine and CATs are FULLY warmed up, your B1S2 is running between 590mv and 800mv. Basically slightly rich(above 450mv(.450v)) This is a good thing. Catalytic converter(s) is/are doing it's/their job(s). They catch and store oxygen.
You will not read a perfect straight line. Especially, on a 200k CAT, the slight oscillations are perfectly normal for this age of CAT.It is however showing signs of aging. Remember cats do were out over time. They fail on less mileage vehicles from engine issues. Also, you have no codes. You have no issues really. Cats typically should last up to 150k with no engine issues.
Kudos for trying to learn about your o2's readings. This takes a lot of studying and practice though. I hope I have explained this clear enough. If not, ask away and I will try to help you. Keep in mind I am just a humble DIY'er who reads/studies A LOT.
Remember also, you have 2 cats feeding into that 1 sensor.(i believe) This can account for the slight variances in the 2nd sensor as well
Just curious.Did you replace with OEM sensors?

If you had a bad spark plug cable(an actual mis-fire) you definitely would have different readings. Just saying
I realize my response is all over the place. Sorry. It's "family night" here with my wife and kids. I snuck away for a sec to "check the forums":)
 






I see nothing wrong with these readings. In short and over-simplified, if you were to look at these voltage readings in a shorter time base/frame rate (imagine stretchering that red line(B1S1) until it resembles a smooth wave) that green line (B1S2) would essentially be a straight line. Like it should be. I hope that makes sense. It's very difficult to explain this with-out writing a book.
Not enough info here to diagnose anything.(your other o2 sensor and STFT's and LTFT's would help) But, assuming this is at idle and engine and CATs are FULLY warmed up, your B1S2 is running between 590mv and 800mv. Basically slightly rich(above 450mv(.450v)) This is a good thing. Catalytic converter(s) is/are doing it's/their job(s). They catch and store oxygen.
You will not read a perfect straight line. Especially, on a 200k CAT, the slight oscillations are perfectly normal for this age of CAT.It is however showing signs of aging. Remember cats do were out over time. They fail on less mileage vehicles from engine issues. Also, you have no codes. You have no issues really. Cats typically should last up to 150k with no engine issues.
Kudos for trying to learn about your o2's readings. This takes a lot of studying and practice though. I hope I have explained this clear enough. If not, ask away and I will try to help you. Keep in mind I am just a humble DIY'er who reads/studies A LOT.
Remember also, you have 2 cats feeding into that 1 sensor.(i believe) This can account for the slight variances in the 2nd sensor as well
Just curious.Did you replace with OEM sensors?

If you had a bad spark plug cable(an actual mis-fire) you definitely would have different readings. Just saying
I realize my response is all over the place. Sorry. It's "family night" here with my wife and kids. I snuck away for a sec to "check the forums":)

Good bit of info there! :thumbsup:
 






Thanks Bud. I'm actually in the middle of helping "a lil old lady" at work with her Silverado running lean and random misfires,etc. The last few months I've been studying so much on o2's and fuel trim, I'm obsessed with it. Also have watched hours and hours and hours of ScannerDanner's youtube videos just on this subject alone:) I have problems
 






Haha but that's the solution! The problem is me wanting to do that stuff and not worry about work or school.
 






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