I think my O2 is going or gone!!

[LKWTSI]

Can someone confirm for me on this log whether or not my O2 is going bad or has gone already. Researching all the posts I can find and using the software info, Pocketlogger, sent I'm looking at the possibility that it may be on the way out.

I'd just like a few honest opinions before I shell out for a new one.

Thanks guys.

In the log you can see the cycling, very well, but the values are going all over the place. The lowest being 0.02(yes below 0.2v) maxing out at .84v. The cycle goes pretty weird sometimes from 0.2v to 0.86v, but my big concern is the very low end values consistently showing less than the desired 0.2v min in the posts and tech articles I have.

 

[AWD_FIEND]

You posted in the Newbie Forum where most here dont have a clue what datalogs are, you should have posted this in the proven members section for better response. I will say though your datalogs are clean, and based on the extreme values of its cylcling the o2 is very suspect. But the other option would be an issue with your tuning at idle, or a bad batch of fuel. Have you been seeing these figures consistently? If so I suspect your o2.

 

[steve]

Can't tell too much from your log. It does look like the sensor is a little slow responding.
How old is it?

 

[LKWTSI]

I guess you learn as you go, I never thought about moving up the experience ladder and posting in more experienced areas..good point to remember.

As for the idle. I've done every thing I can per VFAQ, DSMTuner and Pocketlogger, to get the idle adjusted. Absolutely no boost leaks and the fuel is as fresh as it gets.

I haven't done too many idle logs, as never figured them that important v's pull logs. I guess, I need to watch that. The few idle logs I have recorded, this is pretty much how they look.

The O2 sensor, I have to admit is probably the original, but since I'm not the original owner, I have to presume it's the original one, which is kind of the motivation behind my OP. I seem to be swaying towards the fact I need a new one and do a few more logs to see the difference.

Thanks for the input and suggestions.

 

[DIRQUIN]

Is this an idle log? If so how long was it?

 

[LKWTSI]

The log is 29 sec's long.

 

[DIRQUIN]

It looks to me like its falling off. It works good for a bit then tags the low end for to long. I would definately replace it, especialy if you dont know how old it is. I take it there are no codes showin up.

 

[steve]

I take it there are no codes showin up.

I've been through 4 O2 sensors since new that caused me to fail emissions when they got old and slow. Not a single one of them ever through a CEL.

I haven't searched in a while but oxygensensor.com used to have the best prices for new ones. Don't try and save a few bucks by getting a universal and grafting the old plug on. One mistake and you wind up blowing the sensor ground on the ECU and you'll be back asking why you have a bunch of new CEL codes after changing the sensor.

 

[DIRQUIN]

^^^AGREED^^^ Dont half a** it. buy a real replacement. I work on all sorts off customer rigged stuff. I hate telling customers that they need a new ecu because they new what they were doing and miss wired a sensor. Or an altinator(for a recent example) If you back feed or miss feed an ecu you will blow it. It may cost a little more now, but it saves a whole lot later. I wasnt sure if it would set a code if it was just slow. Some of the newer ecu's will set a watch code for a slow sensor, but never actualy set a code. But that is only some new obdII ecu's. good luck.

 

[LKWTSI]

Good Info'. I haven't seen a CEL or code in my pocketlogger, which is why I was suspect of the thing. But I've been monitoring the value the last couple of days and it consistently bottoms out below 0.2v and lags for a while then spikes back. So I guess it's time for a replacement.

I haven't heard of the universal ones before, didn't know you could do the mod's to get a cheap sensor. Won't be doing that!! New it is and I'll hopefully see some changes.

Thanks for the help.

 

[DIRQUIN]

Did you figure out what was wrong?

 

[LKWTSI]

Not quite yet. Did replace it with a Bosch OEM and the readings are about the same. Looks like I'm possibly dealing with a preO2 leak and it's throwing my readings off. Haven't figured out how much of a leak will cause an O2 to go off, but the leak I have is very small, so the search for the truth goes on.

Did bump the fuel pressure up and will be trying a few pulls to see if my fuel trims start reacting.

If nothing else at least I'm replacing all the sensors and I'm bound to eliminate the problem eventually.

 

[pboglio]

I can get my 02 sensor to "cycle" so to speak depending on how I set my fuel injector deadtimes.

 

[LKWTSI]

I can get my 02 sensor to "cycle" so to speak depending on how I set my fuel injector deadtimes.

I have no way of changing my injector pulsewidth or dutycycle. But will look into it.