O2 sensor replacement

I recall reading somewhere that the OEM could use a wideband upstream and narrowband downstream, that the narrowband could be used to calibrate the wideband (sweep between rich & lean and find where narrowband is centered--then read wideband). In closed loop it should be darn close to correct coming out of the cat, so no real need for wideband after the cat. The cat should be ironing out the emissions. But pre-cat wideband can be more useful to the ECU. Never heard of them as air/fuel sensor though, just always "O2" or more recently upstream/downstream.

My truck is rapidly becoming a beater, but it's only at 160k. Original sensors. Probably keep for another year or two. But who knows.

$229 from Rock is $1 more than Amazon but should get here sooner, would like to install during our warm spell this week.
Wait so you are getting only one sensor for $229? Or more for that price?
 
I recall reading somewhere that the OEM could use a wideband upstream and narrowband downstream, that the narrowband could be used to calibrate the wideband (sweep between rich & lean and find where narrowband is centered--then read wideband). In closed loop it should be darn close to correct coming out of the cat, so no real need for wideband after the cat. The cat should be ironing out the emissions. But pre-cat wideband can be more useful to the ECU. Never heard of them as air/fuel sensor though, just always "O2" or more recently upstream/downstream.

My truck is rapidly becoming a beater, but it's only at 160k. Original sensors. Probably keep for another year or two. But who knows.

$229 from Rock is $1 more than Amazon but should get here sooner, would like to install during our warm spell this week.
Just teasing about the “beater” lol, indeed some vehicles with over 250k on the clock still run like a charm.
Personally, I’ve had better luck with whatever O2/AFR sensor is OEM, but ymmv. As someone mentioned earlier, they do get “lazy” after some time. 160k is probably a good time to replace both upstream “while you’re in there”.
Btw, pay attention to the weatherproof connections, all wires nice and secure etc. A quick spray of contact cleaner while you’ve got them apart can’t hurt. :)
 
And easier way to get them out is to run the engine for two minutes from cold. It’s just enough to warm the manifold but not the sensor.
I cracked loose the two upstreams, they weren't bad actually. Downstream, different story, they felt in there goodntight, and I don't know if I want to mess with them just yet. Upstream I think might be more protected from the elements.
 
I cracked loose the two upstreams, they weren't bad actually. Downstream, different story, they felt in there goodntight, and I don't know if I want to mess with them just yet. Upstream I think might be more protected from the elements.
Yeah, don't know why you're messing with the downstream. They normally never go unless you have a wiring problem. Upstream ones wear out all the time. When they go, it normally means your cats are shot. They're basically just there to monitor that the cats are working. Upstream ones are exposed to raw exhaust and are subject to a lot of switching, downstream ones only see clean exhaust and don't switch much so don't wear out. When the upstream and downstream have the same numbers, the cats are shot.
 
I had a downstream go bad (here) and everything will die eventually, so, since I was underneath, I figured I might as well see if it would break free. If they broke loose, I would apply some anti-seize and put the old ones back, unless if popular opinion was to replace all 4. It seems not, and the sensors do not seem to want to come out, so at this time, I'm not messing with them.
 
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