# o2 Mass Airflow Sensor



## Anonymous (Jun 19, 2010)

Cut these open on the lathe, you'll notice that the ceramic goes clean through to the wire end of the sensor.

If you had thousands to open for processing, I would cut the tip off then compress the sensor using a hydraulic press, then turn it 1/4 turn giving it a tweak with the press to open the canister allowing the broken ceramic to fall out.


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## Chumbawamba (Jun 19, 2010)

And so what are we looking at and what's inside there to make us want to go through all that trouble?


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## Anonymous (Jun 22, 2010)

Chumbawamba said:


> And so what are we looking at and what's inside there to make us want to go through all that trouble?



Maybe not enough to warrant all the trouble of opening them up, if they're to much bother I'll pay the freight for any you want to donate.

Most of the sensors I have scrapped out had gold pins, some I suspect are palladium plated.

Some of the ceramics have gold contact pads while others have the wires brazed on.

Because of the crude methods employed to open an o2 sensor many do not get a chance see the parts before they're broken up into little pieces, so I have taken the liberty to submit pictures from dismantled sensors so that you can see for yourself whats inside.

http://www.platinum.matthey.com/applications/industrial-applications/sensors/


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## Anonymous (Jun 22, 2010)

Chumbawamba said:


> And so what are we looking at and what's inside there to make us want to go through all that trouble?



You tell me - look like platinum, I processed 15 sensors. Yea I know the pot has a crack and will be retired.


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## glorycloud (Jun 23, 2010)

Nice! 8)


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## Anonymous (Jun 23, 2010)

glorycloud said:


> Nice! 8)




Started out with 18 sensors, but lost two or at least the contents when they came loose of the chuck. They're fairly easy to get apart, no need for a press, incineration would have been nice to loosen the plastic plugs crimped at the end.

If anyone is interested I'll post pictures from the wires and connectors from inside the sensors if they test positive for PMs.


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## qst42know (Jun 23, 2010)

Careful with incinerating that plastic. It's likely teflon and highly toxic when burned.


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## Anonymous (Jun 23, 2010)

qst42know said:


> Careful with incinerating that plastic. It's likely teflon and highly toxic when burned.



The crimped plug pushes to the inside using a punch once the ceramic has been removed. I'm pretty much hog tied, my neighbors ya know are too quick to pick up the telephone to report me. No longer on specking terms.

The gloves are complimentary of Monsanto and other herbicide company's they're free for the asking. I've been getting two pairs at a time, made a trip into the city and came home with a dozen pairs from various suppliers.


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## jimdoc (Jun 23, 2010)

Gill,
From an assay on oxygen sensors I got this info;
-Bosch/Kieffgo 4 wire 30 mg
-A/C 1 wire 40 mg
-Universal 1 wire 45 mg
-Bosch 1,(2or4 wire) 45 mg
-N/D 4 wire 60 mg
-N/D 1 wire 70 mg
-NTK 1 wire 80 mg
-NTK 4 wire 90 mg

Hope this helps if you didn't have this info already.


Jim


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## Anonymous (Jun 23, 2010)

jimdoc said:


> Gill,
> From an assay on oxygen sensors I got this info;
> -Bosch/Kieffgo 4 wire 30 mg
> -A/C 1 wire 40 mg
> ...



Thanks Jim, I did not previously have this information. Most of the ones I had were Bosch 4 wire.


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## jimdoc (Jun 23, 2010)

Gill,
On the report I have the Bosch 2 and 4 wire line was left blank under the 1 wire 45 mg amount, so I assumed that it was the same. It may
mean that they were not assayed, so the Bosch 2 and 4 wire figures may be wrong,but my guess is they can't be very far off if thats the case.

Jim


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## Oz (Jun 25, 2010)

Well Jim, that was a very nice commentary sharing assay results that you paid for like that so freely. I have not seen that detail before on the oxygen sensors. 

Thank you for sharing.


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## Platdigger (Jun 25, 2010)

Gustavus, my understanding is the "Mass Airflow Sensor" is on the intake side.


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## butcher (Jun 25, 2010)

mass airflow sensor is intake air to engine, fuel injected engines, two types meter and hot wire types.


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## Anonymous (Jun 25, 2010)

If they're not o2 sensors what be they. These came of the exhaust system between the cat and manifold.


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## Barren Realms 007 (Jun 25, 2010)

gustavus said:


> If they're not o2 sensors what be they. These came of the exhaust system between the cat and manifold.



I have sensors in my exhaust. But Ford spends more for quality...!!!!  :lol: 8) :twisted:


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## butcher (Jun 25, 2010)

There can be one or two oxygen sensors in the exaust for emmission control,


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## Barren Realms 007 (Jun 25, 2010)

Mine has 2 just above each cat I believe. I don't even want to say what it would cost to replace the cat system in my truck.


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## Oz (Jun 26, 2010)

I think everyone is confusing 2 very different items that contain PGM on modern vehicles. The mass airflow sensor on the air intake, then the O2 sensor on the exhaust.


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## Barren Realms 007 (Jun 26, 2010)

I think I started that. Sorry.


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## Oz (Jun 26, 2010)

Barren Realms 007 said:


> I think I started that. Sorry.



No fault on your part. It was an easy mistake, but Gustavus titled the thread “O2 Mass Airflow Sensor”. The mass airflow sensor measures the volume of air at the intake and can contain PGM. The O2 sensor that is prior to the cat in the exhaust does indeed measure O2 (and contain PGM) giving that data to the computer to optimize combustion for the converter to be efficient. Sadly it is not used to optimize combustion for maximum fuel efficiency. To be clear, what Gustavus is processing is an O2 sensor in the exhaust stream.


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## Anonymous (Jun 26, 2010)

Barren Realms 007 said:


> I think I started that. Sorry.



They say a picture is worth a thousand words, I have posted many showing the o2 sensors. 

Jimdoc caught it when he posted his assay results.

From an assay on oxygen sensors I got this info;
-Bosch/Kieffgo 4 wire 30 mg
-A/C 1 wire 40 mg
-Universal 1 wire 45 mg
-Bosch 1,(2or4 wire) 45 mg
-N/D 4 wire 60 mg
-N/D 1 wire 70 mg
-NTK 1 wire 80 mg
-NTK 4 wire 90 mg

Hope this helps if you didn't have this info already.


Jim

Tittle perhaps should have read - ( o2/Mass Airflow Sensors ).

As it stands was hoping someone one chime in on the lacking part of the subject line rather than attack - ouch.


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## Barren Realms 007 (Jun 26, 2010)

Oz said:


> Barren Realms 007 said:
> 
> 
> > I think I started that. Sorry.
> ...



Yep I know the difference in the 2. I was in no way referring to the air flow sensor in my post but to the 
O2 sensor that Gustavas had been discussing and showed in pictures.

Gustavas I don't see anything in the thread that indicates someone making an attack on you or your post.IMHO


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## butcher (Jun 26, 2010)

good information on this thread keep up the good work. I would think the oxygen sensors should give higher yield than the mass air flow sensors, considering the enviroment they have to operate in, I cannot wait to see how this project continues, Gustavus I really enjoy your posts very interesting, I always seem to learn something.


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## butcher (Jun 27, 2010)

there can be two to three oxygen sensors on a vehicle. there are about three types old style narrow range, and newer style wide range, this refers to the range they sense, these both contain platinum and zirconium dioxide ceramic, in the 90's they also had a titanium dioxide thick film narrow range sensor, no Idea any platinum there.

in any of these sensors it would be a good idea to watch for Rh, I am not sure if you will find any, but many sensors of other types can have it.

the oxygen sensors the oxygen sensor generates zero to five volts for the ECM computer, adjusting engine performance for emmision control and a good running engine the sensors also have a PTC heater, this is a positive temperature coefficient heater, testing them as temperature rises the resistance also rises, this is one way to test them put a torch to it and check the resistance change with temperature.


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## Anonymous (Jul 3, 2010)

Pt drop from O2 sensors, this is my first PGM drop, your comments welcome.

Later this afternoon I'll make up some fresh stannous to check if my drop was complete or if there is any palladium in solution. 

Best Regards
Gill


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## Barren Realms 007 (Jul 3, 2010)

Great job there. 8) 

Isn't that the craked pot? :roll:


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## lazersteve (Jul 3, 2010)

Gill,

Nice quantity of precipitate there.

The solution still looks dark green? 

Did you include any iron or copper in the mix?

If not, you may not have removed all of the NOx and it's tied up some PGMs.

Steve


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## qst42know (Jul 3, 2010)

Barren Realms 007 said:


> Great job there. 8)
> 
> Isn't that the craked pot? :roll:



The cracked one was the upper of the double boiler rig he's using.


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## Anonymous (Jul 4, 2010)

lazersteve said:


> Gill,
> 
> Nice quantity of precipitate there.
> 
> ...



Yes your correct Steve there must have been some iron, after securing the orange powder boiled everything down again to be sure I had de-noxed properly then added more ammonium chloride with no further Pt drop.

Tested the remaining solution with fresh stannous and get a very slight color change, as far as I'm concerned it's stock pot fodder.

Best Regards
Gill


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## Anonymous (Jul 4, 2010)

After letting the solution boiled twice that tested barren for Pt settled overnight found these red crystals, what am I doing wrong here.

Best Regards
Gill


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## Harold_V (Jul 5, 2010)

Dissolve a tiny sample of the red crystal in water and test with either DMG or stannous chloride. 

If you recall, Hoke instructs that the platinum metals do not fully precipitate, and if a solution is to dilute, they may not precipitate at all, and generally don't. 

It is possible that what you're seeing is just a little more palladium that has precipitated with time. Testing will determine if that is correct, or not. I confess, I never experienced the same thing, but my usual procedure was to use a Buchner funnel and filter the material while it was still hot, immediately after precipitation. 

In all my years of refining, I can recall only one instance of having experienced what I'd call a full precipitation. It came from a heavily concentrated batch. 

How about posting the results of your test?

Harold


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## Anonymous (Jul 5, 2010)

Harold_V said:


> Dissolve a tiny sample of the red crystal in water and test with either DMG or stannous chloride.
> 
> If you recall, Hoke instructs that the platinum metals do not fully precipitate, and if a solution is to dilute, they may not precipitate at all, and generally don't.
> 
> ...



Too late for that Harold the red crystals from the O2 Sensors Pt drop have been added to the stock pot. I may have overdone it with the ammonium chloride.

Best Regards
Gill


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## Oz (Jul 9, 2010)

Frankly it looks like you precipitated some palladium in that last picture if my screen is showing the color correctly. Ammonium chloride will do that, but it is a slower reaction than the platinum. This is why many platinum precipitations are orange instead of the canary yellow.


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## skippy (Apr 24, 2013)

Does anybody know if the heater rod on the oxygen sensors has anything worth bothering with in it? I just finished processing 60lbs of oxygen sensors and got a bit under ten grams of cemented platinum of unknown purity. I don't want to sound like a baby here, but really I was hoping for a little more, and I am wondering if I am missing any value if I just process the sensor nose.


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