o2 sensor diagnosing

[liamkeough88]

I'm moving my post in regards to this subject from my thread about my 2.9 bogging down to here..:he more I've been reading the more I have begun to suspect it may be a faulty o2 sensor.

I pulled the o2 sensor and did the " heat up with a torch and measure voltage test."
Results are as follows:
Voltage ranged in the .8's to as high as 1.32. No issues dropping down once heat was removed.

If this method of testing is accurate then those kinda volts would certainly cause a reaaalllly rich mixture.
Possibly my problem? Thoughts?

update*
Perhaps its just the inaccuracies of this testing method but I just spent a little more time doing it again and got consistent readings in the .89 to .91 volts range when heat was directly applied with the torch.
Update*
Just brought home a new sensor and performed the same test. Voltage peaked around .39-.41 volts. Possible confirmation of my old one being faulty?

 

[ab_slack]

I have no idea about that test. Sounds like it could be destructive.

Generally what I have heard as a first cut test with O2 sensor is simply unplug it. Does vehicle run better with it unplugged? If so very well could be a bad sensor. If it doesn't run better look for problem someplace else.

With the sensor unplugged it will go into open loop. This won't be the cleanest emissions nor most fuel efficient, but should at least run reasonably well even if power is down a bit. Improvement is a strong indicator of O2 sensor issue. If it continues really bad than it is some other issue going on.

 

[RonD]

I have never tested an O2 sensor, except by watching OBD reader so can't say if that method tells you anything of value.

But if a new(assuming good) O2 sensors tests at 0.4 and suspect(old) sensor tests at 1.0 when tested then I would replace the old O2 sensor.

O2 sensors use a chemical reaction to compare outside oxygen levels with exhaust oxygen levels, this reaction generates its own power, the chemicals wear out over time, spec is 80k-100k miles for recommended change intervals.
And when worn out they tend to go "rich"(higher voltage) because they are no longer detecting oxygen in the exhaust because chemicals are gone.

To test with an OBD reader, warm engine/idling, you can pull a vacuum line and O2 voltage should drop almost instantly(lean), then add propane(unlit torch) to intake air and O2 voltage should jump up(rich).
O2 numbers should be changing quickly when normal, slow reactions are a sign of failing sensor.
Voltage range should be .2-.8 normally

 

[liamkeough88]

I'm not even sure when or where I heard of this particular testing method but the theory seems sound. Lol. I'm sure if you search YouTube for "o2 sensor testing" some vids of the torch method will come up.

 

[freedom5]

O2 sensors aren't that expensive and not too hard to replace. I'd just replace it. I also replaced the EGR valve and the TPI.