Please help me interpret new scanner output

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artbuc

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OK, you guys shamed me into getting an OBDII code scanner so now you have to help me figure out how to use it (just kidding, of course). Here are a couple questions on the output on my Actron CP9575:

1999 Toyota Avalon 1MZFE V6 - According to Toyota, output from A/F sensors at 2500rpm should fluctuate +/- .08v (.7-.62v) and, after quick deceleration from 4k to idle, output should spike up to .76v. On my car, output is barely changing at 2500rpm - about +/- .04v. And, output spikes to only .72v instead of .76v on decel from 4k. Is this good enough or are my A/F sensors getting lazy? Thanks.

2010 Acura MDX - Wow, this car has so many PID outputs it makes my head swim. Problem is there are many multiple outputs. For example, I have 3 Coolant Temperature outputs. Is this the same sensor displayed 3 times for some reason or is it showing me three different sensors. If they are different sensors, how do I know which is which? Thanks.
 
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At idle your primary O2 sensors should fluctuate in a sin wave. The rear O2 sensors show stay below 450mV indicate the cat(s) work. When you rev it up both front and rear O2 sensors should spike upward then regain their stand pattern at idle.
 
Originally Posted By: beast3300
At idle your primary O2 sensors should fluctuate in a sin wave. The rear O2 sensors show stay below 450mV indicate the cat(s) work. When you rev it up both front and rear O2 sensors should spike upward then regain their stand pattern at idle.


I'm not sure if makes a difference but my car is CA spec so my two upstream sensors are wide-range air/fuel sensors. Downstream is a regular heated O2 sensor.
 
Originally Posted By: ChiTDI
How many miles on that 1MZFE? Those stats suggest a lazy a/f sensor or two to me.


112k. One A/F is original and the other has about 30k on it.
 
Originally Posted By: artbuc
Originally Posted By: beast3300
At idle your primary O2 sensors should fluctuate in a sin wave. The rear O2 sensors show stay below 450mV indicate the cat(s) work. When you rev it up both front and rear O2 sensors should spike upward then regain their stand pattern at idle.


I'm not sure if makes a difference but my car is CA spec so my two upstream sensors are wide-range air/fuel sensors. Downstream is a regular heated O2 sensor.


My boss has the same car with platinum edition. I just looked at the front O2 sensors they are 4 wire. I think those are narrow band.
 
Originally Posted By: beast3300
Originally Posted By: artbuc
Originally Posted By: beast3300
At idle your primary O2 sensors should fluctuate in a sin wave. The rear O2 sensors show stay below 450mV indicate the cat(s) work. When you rev it up both front and rear O2 sensors should spike upward then regain their stand pattern at idle.


I'm not sure if makes a difference but my car is CA spec so my two upstream sensors are wide-range air/fuel sensors. Downstream is a regular heated O2 sensor.


My boss has the same car with platinum edition. I just looked at the front O2 sensors they are 4 wire. I think those are narrow band.


I also have the Platinum Edition too. The CA emission cars took the 4 wire wide band A/F sensors. Two of the wires are for the heater and the other two for the sensor. I was disappointed to discover this because the A/F sensors are twice the cost of the regular O2 sensors. In fact, the A/F sensors in my Avy are the exact same ones in our previous Lexus RX300. Ain't California wonderful?
 
Wide band/narrow band is not a function of how may wires go to it.
Narrow band is like a switch -lean or rich. Very fast readings give you a good average.
A wide band sensor reads and permits an exact voltage for whatever AF ratio.
 
Compare the two primary O2 sensor outputs. Also watch the STFT and LTFT readings along with MAF. The wideband O2 output is going to be steady and does not fluctuate like a narrowband. As long as your computer is successful in keeping the A/F mixture to be stoichometric, the O2 reading will stay steady in the middle of the range. Watch the fuel trim ranges and see how much variation is there.

The wideband O2 sensors are expensive. If it is not working, you will get the appropriate code from the computer.

Since this is a 1999 model, it is using the older protocol which has limited bandwidth and scanner can only get few (ten) samples per second. This is just not enough to watch the O2 voltage output in realtime.
 
I just checked the primary A/F O2 sensor on my Camry. I got 0.46-.96V range on the scanner while revving up to 3K at idle. This is the replaced A/F sensor. Even though it came in a Bosch box, the sensor was most likely a Denso as it was made in Japan.

On my scanner, I only selected STFT/LTFT/O2Voltage and selected to graph the O2Voltage. Scanner gives me max and min along with the realtime graph.
 
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