was reading on another forum that fords run a narrowband oxy sensor. it only reads 0 or 1 volt. i dont think that could be right. usually stoich is .45 volts. anyway i know i asked before but when should i swap a sensor?

and if they are narrowband, could i swap it for a broadband?

Cheers

their life is around 80-100,000k's.

only 80 bucks, doesnt hurt to swap it.

and no, you cant swap it for a broadband sensor as the ecu wont read it

do they loose accuracy or do they just stop working and are they sipposed to be replaced at 100k

Are they best replaced with a genuine one are are there good after market ones available?

oxy sensor, same s**t different smell.

just head down to auto one, got mine there for 80 bucks.

No... a narrowband sensor provides voltage outputs like this:



An interpretation of that graph demonstrates that the narrowband is only accurate at/around stoich. Outside of stoich, all it is capable of telling you is that the mix is "rich" or "lean".

How lean? It cant tell you - see how there's almost no voltage difference between 15:1 and 17:1 air/fuel....

Therefore, the best that an EFI system can do with this info is to switch between rich and lean conditions - in an effort to have stoich as the "average".

A wideband is a very different animal. It needs a controller, as well as an EFI system that can read its very different output.



You can discreetly identify the exact air/fuel....




Unless you well and truly ruin the sensor (using non sesnor-safe fluids/sprays etc), then they dont usually lose any "accuracy" per se - they become a lot slower to respond... remembering that, based on the above graph, the EFI system works best if the o2 sensor reacts quickly and is able to pick up on the rapid changing between rich and lean.

Yeah... after 100k they are usually getting a bit "slow".

why the f**k would ford use them for then?

In terms of acheiving the desired economy and emissions levels - they do a fantastic job. That's really all they are there for - to let the ECU know how close to complete combustion the air/fuel mixture is.

Particularly as the engine degrades over the years - the ECU coupled with the oxy sensor can still keep emissions in check.

Oxy sesnors like this are ignored when you've got the hammer down - the ECU is "pre programmed" for power settings and doesnt need oxy sensor feedback.

The additional cost and complexities of a wideband o2 sensor are not warranted for factory cars. I dont think many - if any - cars have ever come out with a wideband o2 setup.

Thats pretty much it. Narrowbands are funny little creatures. Useless for performance tuning, barely capable of economy tuning, terribly inaccurate, not actually needed to run the car yet still manages to be very useful.

Widebands on the other hand are very accurate and great for precise tuning but are fragile and expensive.