O2 Sensor Voltage With Tune

[joefnh]

I have recently started using the SCT Live Link software with my new laptop to see how the engine is running as I change the tune with the Pro Racer software.

Recently while monitoring the O2 sensor voltages for bank 1 & 2 I noted that bank 1's voltage readings were constantly fluctuating from .06v to .845v so frequently that on a chart it apears almost as a solid color. Bank 2 looks good and responds to throttle and load as expected.

Any ideas of what might cause this type of fluctuation? Where do I begin trouble shooting? These O2 sensors are new Bosch changed 5 months ago

Thanks, this site has been a great source of information

--Joe

Note the red line is bank 1 front while the yellow is bank 2 front.

 

[joefnh]

Sorry the original message did not include the image. From what I understand about how O2 sensors are supposed to work, the yellow line (bank 2 front) is not working properly.

Whick side of the engine is bank 2?

--Joe

 

[ExplorerDMB]

It doesn't look like it's switching like it should if that's the front one. However, I know somewhere ellse there was a post about someone having a odd 02 sensor reading, and when they contacted Bama Chips - they said it was bc of the tune. You might want to research that.

-Drew

I'm going to move this to the Tuning/Computer section.

 

[joefnh]

Thanks for the reply. I believe that post was refferring to the rear o2 sensors, Doug has been known to turns those off.

That is the from O2 sensor labled as bank 2 front, the bank 1 front (The red trace) looks like it is swithching correctly. Of the 4 O2 sensors that one ( the yellow line) is the only one with that problem.

Whick side of the engine is bank 2 on?

--Joe

 

[ExplorerDMB]

here some information:

http://autorepair.about.com/library/faqs/bl026h.htm

-Drew

 

[joefnh]

Thanks for the replies

I finally figured out the problem today. While troubleshooting this problem, I had replaced the o2 sensor twice with Bosch sensors purchased at Auto Zone a local car parts store.

Apparantley the 03 Ford Explorer uses 2 types of sensors, a 3.3 ohm and a 6 ohm heater coil type. The 3.3 ohm ones are used in the front or upstream positions while the 6 ohm ones are used after the cats. Auto Zone apprantly did not know this.

In Fords service DVD manual the reason given for this is so that the front sensors can heat up faster (as the 3.3 ohm heater will draw roughly twice the current of the 6 ohm heater) to enable the engine to enter the closed loop mode sooner.

After swithching out the sensor with the correct model it ran fine.

Thanks again

--Joe

 

[ExplorerDMB]

good information. Glad you updated your thread with a conclusion. Thanks

-Drew

 

[JohnC76]

Holy cow! I think I have the exact problem with my Mustang GT (found this thread while searching google)!

Can you look at my sct datalogs and tell me if they look exactly like yours?

Here are the link!

Here is the cold start: http://home.comcast.net/~nx330mustang/cold_start.csv

The rest of these are normal driving, stuck in traffic idling, and a few WOT runs.

http://home.comcast.net/~nx330mustang/drive_1.csv

http://home.comcast.net/~nx330mustang/drive_2.csv

http://home.comcast.net/~nx330mustang/drive_3.csv

http://home.comcast.net/~nx330mustang/drive_4.csv

http://home.comcast.net/~nx330mustang/drive_5.csv

http://home.comcast.net/~nx330mustang/drive_6.csv

http://home.comcast.net/~nx330mustang/drive_7.csv

Thanks for the help in advance!

 

[JohnC76]

BTW, My O2's have read as crazy as:

B1 was reading 0.41386 while B2 was reading 0.198242 @ 1457.25 rpm's.

Another instance I seen B1 at 0.427734 while B2 was 0.610352 at 1217 rpm's.

In cold weather on cold starts it will start and run like it has a big cam and smell rich (off road H pipe = no cats) for a few seconds or until I hit the gas. Then I get a rolling idle after that until it warms up.

Did yours have any of those symptoms?

 

[local7teener]

I have a 98 mountaineer v8 and i'm using the livelink software to monitor my o2's.. anyway my question is on the sin-like wave of the o2's How does the computer read a rich/lean condition? is it a smaller variation from the high point of the wave to the low point? A higher peak in the wave or a lower bottom of the wave?? I see the osilation in the voltages but don't understand where the computer interprets the condition.

Thanks