Upstream O2 sensor question

The O2 heater resistance is about 11-16 ohms at 68 F and about 23-30 ohms at 1,472 F (operating temperature).

The ECU monitors the current through the heater circuit, so you could trick it with a 25 ohm, 10W resistor in parallel with the heating element if its open.

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These 02 sensors have a heater in them to bring them up to temp so they can read quickly to regulate emissions . 

With the heaters burned out they will wait until the car is upto temp by the exhaust and do their thing.

One thing about 02 sensors that is never discussed and that is 02 sensors are rated to 80k miles and it is recommended that they are changed. What happens is as the 02 sensor gets old they will drift towards reading lean and that will cause the computer to add fuel which is bad for both millage and emissions. 

Most people only replace them only  when they show a fault which is the wrong way to go about it.  

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Bought my car with 114k with an O2 sensor code, looked like they were original to the car. I changed all 3. 

@haloruler64

I replaced all of my O2 sensors at 75000, no codes present. I do not like "on the road" failures.

Hey, buying a car with a CEL means you save some money. I didn't mind doing O2 sensors right as I bought it.

I I got my '01 at 60k miles, and have 360K miles on my car, so I have history..  

• My Cat o2 went out at 120K,250K, and changed them all at 300K when I did the engine for the first time
• My Main '02's lasted till 300K..  no apparent drift as I have a wideband as well watching things
• When you go to 'Open Loop' during acceleration, the heaters will power back in a PWM style of heat reduction
• My Tranny went out at 175K miles, and the replacement made it to 300K when I did the Engine.
• My rear pads and Rotors lasted till I smoked them at 200K when my Parking Brake PARTIALLY froze on in the winter..  it was ugly
• My front pads made it to 300K
• My Struts went at about 120K miles.. I went to STIFF coilovers, and are still on the car. Did I mention they are stiff!
• Gapped my factory plugs at 175K miles and finally replaced them ay 200K, then again at 300K..
• I did one rear hub bearing at about 280K, and the other Hub bearing at about 310K miles.
• all hose rubber made it ti 300k Engine change.
• My alt made it to about 280K..  I kept that same one in the replacement enging

As you see, 300K miles was the Major overhaul for my Spyder..

Its been a great car

Cap

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Three  things here.

1. Your reading is normal. Fill the oil to where it is full on the side that reads a little lower.

2. Clean oil is not indicate anything. Dirty oil is a good sign the oil is doing its job

3. There is no low oil light, that light is directly related to oil pressure. If the oil light is illuminated it means your engine is being damaged and if it’s not shut down in time (matter of seconds) the damage is irreversible and catastrophic. That is why it’s an idiot gauge.

The same with the water temp gauge. It never reads a little high. When the needle pegs and you drive it the engine will melt.  

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Posted by: @nottamiata

I thought dirty oil was a sign of any number of problems like poor ignition, degradation of engine components, poor piston ring seals (of particular concern with a 1ZZ, but not as much with facelift cars), oil contamination.

Not an attempt to bicker, though, just picking up more wisdom through discussion with anyone willing to spend the time. I also understand that simply appearing clean does not mean it is still good.

Not necessarily and not always. You can tell when an oil is obviously bad if it looks highly unusual like a milk shake or if you smell fuel. Other that that only an oil analysis can tell you the state of the oil and the state of the engine.   Sometimes you can be using conventional oil for a long time that shows up clean for the first 1k miles and switch to synthetic and now the oil is dirty in 50 miles.  

Oil has detergents and dispersants to suspend deposits and it can remove previous deposit formation over time. Oil is a highly evolved subject but unfortunately there are a lot of wives tails that perpetuate the internet.  It’s also an evolving technology that is constantly in flux.  What might have been true 10 years ago has flipped with newer certs and technology formulations that are highly complex.   

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