O2 sensor question

Toy4x4 · Mar 10, 2003

If there has been an oil burning problem, can it affect how the O2 sensor performs? I had it replaced at 80K (now at 120K) approx. 4 years ago. Can it be cleaned?

[ March 10, 2003, 09:53 PM: Message edited by: Toy4x4 ]

digitaldrifter91 · Mar 10, 2003

i dont think the burning oil is the cause of a bad 02 sensor for the o2 sensor is outside the crank case...and is mainly for regulating emissions by the ecu.

ur burning may be that ur car is old or something else...maybe its ur oil weight...im not certain cause u told me so little.

the 02 sensor can be cleaned but only a couple have tried. dont buy a new one i think its a waste of cash...@100 dollars each =).

i burned oil before and upgraded my oil weight. but now after about 6 years im burning again so im doing an auto rx treatment.

mkosem · Mar 12, 2003

O2 sensors are prety sensitive. I'd sar replace it or leave it alone. Trying to clean it may do more harm than good.

--Matt

digitaldrifter91 · Mar 13, 2003

there was a post a long time ago about this...do a search on 02 sensor or something i knwo its out there

cryptokid · Mar 15, 2003

burn the end with a propane torch until it looks good again.

Malibu · Mar 15, 2003

I think you said your engine was burning oil at the rate of 1000-1500 miles per quart. That is not a radically great amount and not likely to harm the sensor.

If the sensor was ever harmed in any way you'd notice a drop in gas mileage and a bit of a drop in power.

Greg · Mar 23, 2003

quote:

Originally posted by digitaldrifter91:
i dont think the burning oil is the cause of a bad 02 sensor for the o2 sensor is outside the crank case...and is mainly for regulating emissions by the ecu.

ur burning may be that ur car is old or something else...maybe its ur oil weight...im not certain cause u told me so little.

the 02 sensor can be cleaned but only a couple have tried. dont buy a new one i think its a waste of cash...@100 dollars each =).

i burned oil before and upgraded my oil weight. but now after about 6 years im burning again so im doing an auto rx treatment.

i don't trust the first 3 paragraphs.

ekrampitzjr · Mar 24, 2003

Burning oil can and will contaminate O2 sensors. I've heard of the torch trick too, but for the hassle involved, you may as well just buy and install a new one.

There are three main killers for O2 sensors:
1. Oil burning; takes a little time; leaves brownish/blackish residue
2. Antifreeze from head gasket leaks; leaves grayish/whitish residue
3. Silicone from improper gasket-maker or gasket seal material; coats sensor rapidly and cannot be removed readily
A fourth is contaminated fuel. I've had the pleasure of getting a bad tank of gas and then having to replace the leading O2 sensor.

digitaldrifter91 · Mar 24, 2003

i stand corrected

RobZ71LM7 · Mar 25, 2003

Running really rich can kill O2 sensors as well.

Cressida · Mar 25, 2003

I've yet to be convinced how an O2 sensor goes bad or dies. Except for the internal heating element in those models that have one, I don't see any part that moves or is consumed up within 80-100K or more miles of driving.

Now I have had one go bad so I know that that happens. But my theory is that is is just a case of contamination on the sensor element or perhaps an electrical short ?

I've tried cleaning old ones in a mild acid (citric) bath without any conclusive results.
The acid did clean up the sensors but I don't have quality testing equipment to tell if it is making a difference on the NGK sensors that I was working with.

Now that I know about Neutra 131 and Auto-rx I wonder if a soaking in one of these products could rejuvinate a lazy sensor?

I think the jury is still out on O2 sensor cleaning. The type of people who spend their time on this board will eventually figure out how to clean these things - at least I hope so.

[ March 25, 2003, 09:39 PM: Message edited by: Cressida ]

Malibu · Mar 25, 2003

Cressida, the cost of a new Toyota OEM oxygen sensor is $105 and since gas mileage goes up 1-2 MPG after replacing the sensor, the gas savings pays for the cost of the sensor in as little as 10,000 miles.

So it's false economy to delay oxygen sensor replacement. Also, failing to change the oxygen sensor BEFORE it is totally worn out will shorten the life of other expensive emmission control components like the EGR valve and catalytic converter (because a lazy sensor = a richer fuel mixture = more incompletely burned hydrocarbons for the EGR valve and cat. converter to deal with.

RobZ71LM7 · Mar 25, 2003

Sometimes cleaning works sometime it doesn't. Not all O2 sensors are $100. Many lie in the $20-55 range.

ekrampitzjr · Mar 25, 2003

Yup, I forget the effects of running rich. That will leave soot contamination on the O2 sensor, not to mention the catalyst.

You're right that there really aren't any moving parts to wear out in an O2 sensor. The problem with contamination comes with the high exhaust temperatures, which in effect bake contaminants on the outside and kill the ability of the sensor to make proper signals. Even without that, heat can change electronic properties over time.

The older one-wire O2 sensors are actually pretty cheap, typically $30 or so. The newer 3-wire sensors, which contain provision to heat the sensor when the car is first started, are the expensive ones. New cars use the preheat jobs, which is why these sensors cost $100+. You can thank the feds for this state of affairs, by the way.

A few years ago I tried cleaning O2 sensors after removing them with a strong solvent such as Berryman's B-12 Chemtool. The sensors had no visible contamination, but the B-12 seemed to help for a short while. I doubt that the B-12, strong as it is, would help on baked-on contaminants.

cryptokid · Mar 25, 2003

im tellin ya, propane torch works reel good.

DEWFPO · Mar 28, 2003

O2 Sensors can get 'lazy' as well. That means they don't respond as quickly to changes in the exhaust flow. But they still work.

Howard · Mar 28, 2003

quote:

O2 Sensors can get 'lazy' as well. That means they don't respond as quickly to changes in the exhaust flow. But they still work.

I had 2 of these 'Lazy" O2 sensors in my 96 F150. They did not throw a code but responded very slow. I graphed out the response of the sensors and they were taking approx 0.5 seconds to respond and send a signal to the computer to change the mixture. I have been told that they should respond in approx 2 miliseconds. I changed out both of the O2 sensors and the truck ran smoother and the fuel mileage went up about 3 - 4 mpg. I don't understand why the engine ran smoother but the mpg was worth it.

HL

Robbie Alexander · Sep 10, 2003

quote:

Originally posted by Cressida:
I've yet to be convinced how an O2 sensor goes bad or dies. --snip--

I would like to know how they go bad.
Mine are around $150-180 each.
My front one went out at 80K and I gave high dose of fuel conditioner and it went away, following this it came on and re-treated... then going out about three times before it stayed ON for about 200 more Thousand miles, then getting to the point that no matter how much I put in it would only last for a week or so.
I suspect it's like a PLUG and just burns away.

Virtuoso · Sep 11, 2003

$150-180 for an O2 sensor? Yikes. I thought parts for my SHO were expensive.

Mine uses a 3wire sensor that's around $45. Automatic SHOs use a 4wire one that's about the same price.

O2 sensor question

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