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O2sensor Surprising voltage.

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17 Jul 2017 06:28 #11212 by Mathis
O2sensor Surprising voltage. was created by Mathis
Hello forum. I'm quite new in electronics diagnostics and have been following Paul for a year, and today I made my first field job a p0420 on a hyandai Santa Fe,
The money lamp had been lit but went out. The car had not passed inspection due to the fault code in the system.


Now to my question, When I connected the scanner and looked at the sensors they had a scale of 0-800 mv and switched in that area and the rear sensor was in the upper range
But the scanner was so slow so I could not trust it when I added propane so I connected the scope instead and then it became bizarr because with the engine of i red 0 volts at the signal... key on engine of 5volt,... and when the engine ran it switched between 1.8 and 3.5 volts.

it hold rich about 8 sek after the propanetest so i just cleared the code and shipped the car. btw the emissions from the inspection was perfect so i saved about a 1000 dollar to the costumer. It only faild due to the faultcode

I dont understand the sensor, it was´nt a wideband, it was 4 wire and 4 color, black, white blue and orange or yellow i think.


peace.

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18 Jul 2017 12:08 #11234 by Mathis
Replied by Mathis on topic O2sensor Surprising voltage.
Today the bizarrenes continued with the Santa Fe.

We went to the inspection and it went well and when we got home and I wanted to take a second look at the o2 sensors
so I used brake cleaner to force it rich and what happens?

The sensors dive to LEAN and the fuel trims gets maxed out RICH, the fuel trims stayed rich and the o2 sensors stayed lean about 30 seconds despite that i had removed the brakecleaner, i had to rew the engine to get the traces normal again.

When I introduce the brake cleaner again, the o2 sensors took a dive aaagain but this time the fueltrims took fuel away.

This time I used a scanner with a very clear graph.

This is so bizzar, the sensors behave like wideband but the tracks are common o2 sensors and I know it's not widebands all 4 sensors give the same trace while the computer seems as confused as me.

Anybody?

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18 Jul 2017 13:36 #11235 by Ben
Replied by Ben on topic O2sensor Surprising voltage.
What year and engine is this santafe? What wires are you scoping? Which sensor are you scoping? Are they fully warmed up? You should be able to see the added fuel on the oxygen sensor even with a low refresh rate scan tool ,1 trick for slow refresh rate is only load the pids your viewing not the whole list.

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18 Jul 2017 15:09 #11238 by Andy.MacFadyen
Replied by Andy.MacFadyen on topic O2sensor Surprising voltage.
It sounds like a Titania narrow band sensor I haven't seen one in years, Rover used them on the 800 series, unlike plain jane Zirconia sensors they vary a bit between manuafacturers. Unlike Zirconia generally they need a 5v supply and work by varying ressistance (hence current) rather than generating a voltage. When running closed loop an upstream Zirconia sensor an oscilloscope should oscilate between about 0.4 and 4 volts.


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18 Jul 2017 16:20 - 18 Jul 2017 18:01 #11239 by Mathis
Replied by Mathis on topic O2sensor Surprising voltage.
Dude, It was totaly Grey, white, black and yellow hahaha and the scope did definitely read 5 volt k o e o at the signal. I set the scope at +-2 volt and its screamed OUT OF RANGE when i turned the ignition on....I just "WTF" Well it explain a hole lot... Thanks a lot Andy.

However it was the sensor after the
suspected bad cat i put the scope at, but all 4 sensors had different wirecolor, i dont remember if they had the same color or if it only was the harneses who had differnt colors. And all 4 sensors acted
backwards
Last edit: 18 Jul 2017 18:01 by Mathis. Reason: forgot something

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19 Jul 2017 07:40 #11270 by matt.white
Replied by matt.white on topic O2sensor Surprising voltage.
Did you happen to spray brake clean into the intake pre air cleaner and soak the filter a bit? It takes ages for the fumes to leave the filter.

Don't ask how I know.


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19 Jul 2017 09:07 - 19 Jul 2017 09:09 #11271 by Mathis
Replied by Mathis on topic O2sensor Surprising voltage.
No, I took the lid of, and sprayed upwards, not directly in to the maf but up in the lid.

It was just like the pcm got stuck, but the crazy part where that the fueltrim was stuck at +30% with and after brakecleaner.

I mean i wish i had recorded it..haha
Last edit: 19 Jul 2017 09:09 by Mathis.

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20 Jul 2017 10:48 #11287 by Andy.MacFadyen
Replied by Andy.MacFadyen on topic O2sensor Surprising voltage.
Titania sensor works in a completely different way to plain jane Zirconia sensors. The Zirconia sensor generates voltage like a battery, but the Titania sensor works more like a variable resistor --- or think of it like coolant temperature sensor.
On a , as with wideband sensors the voltage is reverse a lean condition gives a higher voltage, a rich condition gives a lower voltage. This trap can confuse both some scantools and the technician.

Wideband sensors were developed from Titania sensors.

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20 Jul 2017 11:11 #11288 by Mathis
Replied by Mathis on topic O2sensor Surprising voltage.
Does the titania read backwards to? Sorry my english gramma is out of wack.

I mean it doesent make sense that there is 4 wideband sensors in a -02 hyndai..or does it?

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20 Jul 2017 11:25 - 20 Jul 2017 11:31 #11289 by Andy.MacFadyen
Replied by Andy.MacFadyen on topic O2sensor Surprising voltage.
Some late 1980s and early 1990s models used Titania sensors because they were more resistant to lead contamination than Zirconia sensors and when new they also switch hi-lo-hi at higher frequency than Zirconia so were chosen for some appications.
The main user I know of the basic bi-polar titania sensors on some models were Rover & Land-Rover, Jeep, Vauxhall-Opel, BMW --

NGK/NTK were the only manufacture of the simple bi-polar titania sensors.

Developed by Bosch wideband sensors are a hi-tech development of the bi-polar Titania sensor.

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Last edit: 20 Jul 2017 11:31 by Andy.MacFadyen.

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20 Jul 2017 12:32 #11290 by Mathis
Replied by Mathis on topic O2sensor Surprising voltage.
Yes. I did post an email to ngk yesterday about this.

Yea, i cant rep my head around this..

Anyway the cel has not resturn and the car did pass the inspection.

To be continued

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20 Jul 2017 15:25 #11291 by Andy.MacFadyen
Replied by Andy.MacFadyen on topic O2sensor Surprising voltage.
It is really no different from a temperature sensor or pressure sensor, you have a refrence voltage (can be 1v or 5v) as the resistance of the sensor changes with the oxygen content of the exhaust gas the voltage droping across the sensor changes.
This might help link to tomco-inc.com PDF


Zirconia sensor work completely differently they are effectively a miniature fuel cell the generates a voltage from the fuel and oxygen in the exhaust.

You can bench test both type of binary (bi-polar) sensors on the bench with a multimeter and the flame of a blow lamp. To test the Zirconia use the resisstance scale, for the Zirconia use a low voltage scale. In both cases move different parts of the flame over the sensor and observe the readings on the meter.

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09 Oct 2019 18:36 #34128 by Dtnel
Replied by Dtnel on topic O2sensor Surprising voltage.
I know this is a post that say couple years old and then some. I stumbled across this by doing a search for 3.5 Hyundai Santa Fe.

I know you were able to get the code cleared and passed the inspection but I'm wondering what the end result was in regards to did you have a faulty part, did you throw the parts cannon at it and get lucky with the first part or did you do some more Diagnostics and figure out what you truly had going on?

There's always the did you ship it to another shop and let them work at it as maybe you ran out of time or patience working on this? I try not to run out of time. I just shove it for another day since the pain in the butt ones generally are my vehicles.

Just saw the post and thought I would ask as I read through the thread and was curious.

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