Zander916

I have a k&n intake, zzp catted downpipe, and canned tune. All of which I've had for a long time.
Recently out of nowhere I'm getting secondary o2 codes. (P0141, p2096, p2270)
Along with those the afr's are crazy. Just cruising they will hang around 13 but have dipped to 9.9.
The ltft reads 0.0 and the stft bounces all over hell from -6 to 23.

I cleaned the air filter and the maf hoping to have some luck, but none. I looked around for leaks but didn't see any.
If I didn't see the gauges and mil I wouldn't know. It seems to run fine. No misfires, builds and holds boost no problem.
Oh I should point out that obviously I can't give the ic endtanks a good lookover. I can see the bottom and backside. They look fine. The bottom of the intercooler itself is flawless. Not a single mark. I'm very careful.

gone_in_10_sec

First, its possible the SHO2 [Second Heated Oxygen Sensor] is on its way out..

A code P0141 may mean that one or more of the following has happened:

-Theres open or short to ground in the wiring harness [check the wire leading into the sensor itself]

-Internal short or open in the heater element [again check the wire leading from the sensor itself and the wiring harness that leads to the ECM also]

-SHO2 heater circuit wiring high resistance [you may have to back probe the sensor and check for resistance]

-SHO2 heater element resistance is high [again you may have to back probe the sensor and check for resistance]

Second, is the intake oiled and what did you use to clean both the K&N air filter & MAF sensor?

jacream_booSSted

^ this guys a boss!!

Zander916

I used the k&n products to clean and oil. The filter dried overnight.
I used electronic cleaner on the maf. Couldn't find maf cleaner.

It should be noted that these issues existed before I cleaned anything.

Zander916

Thanks for your help.
I have a thought, see what you think.
Could it be the primary O2? My reasoning is that if its running so rich because the primary o2 is reading wrong then raw fuel might be screwing up the secondary. The one thing that I.find VERY odd is that the ltft stays at 0.0. It doesn't move and until now I've never ever seen it stay at 0.0. It's like it isn't able to be determined but why no mil for that... I have no idea.


Possible?

EDIT: Okay check this out. I've only just started investigating this so I'm discovering things. I've been clearing the codes and they'll stay gone for a while, then come back. I just went out to the gym, picked up some food and came back. I didn't get any codes for a while. Just as I started the car again to come home I got P2270, and P2195.
P2195 is bank one sensor one (primary O2 rich shift). So I think I'm on the right track here. Also, as soon as the MIL came on, EVERYTHING returned to normal. The AFR stayed normal, around 14.7. The STFT stayed +/-5 and LTFT started reading finally.

gone_in_10_sec

[1] normally the MIL will come on when the ECM sees a value it doesn't recognize, but it can also record a MIL and not turn on the Light, but it will keep a record of it depending on many drive cycles [normally 2], it waits to see if the problem is/isn't recurring..

[2] this is good, this means either the MAF or HO2S 1 or 2 is definitely gone, because the ECM is getting info from other sources, like the MAP and other sensors.. many auto manufacture do this as a backup - if one or two sensors fail..

FYI: as for K&N oil filter cleaner - it takes atleast 36-48 hours to fully dry out.. i know because i had the same problem in the past, with a refresh and cleaned K&N oiled air filter.. your best bet is to get K&N dry filter.. b/c the oiled air filter will kill MAF sensor again on a really rainy day..

use this instead: CRC Mass Air Flow Sensor Cleaner - 11 Wt Oz. #05110 - i've found spraying down the sensor atleast 3 times - really soaked - thoroughly cleans the sensor out and you'll actually see the solvent turn brown from grime and build up..

Zander916

Hey, thanks for your help!
I do sincerely appreciate it. It's nice when members take the time to help out.

Just a little update and then I'll update when I get it resolved.
I'm 99.9% sure now it's the primary O2 and not a boost/vac leak, maf problem, or anything else. One is obviously, the MIL codes point to it.
I never cleared the codes after this last time. Then today again the STFT were really skewed badly although LTFT's seemed fine. Just a bit ago on my way home I was coasting down a hill. The STFT's maxed out. 29+ and AFR read about 9.5 and gas mileage said 17... going down hill! The car started chugging and I thought I was going to have to pull over on I80 and shut that bitch down. Then, all of a sudden like a light switch it just snapped out of it. I think the PCM figured out that it can't rely on the O2 any more. AFR's went to normal, STFT's went to normal. Stayed that way for several miles all the way home.

So I'm pretty certain it's the primary O2 because if the MAF were that bad it would toss out a code for it I'm pretty sure and a leak wouldn't just suddenly disappear.

New O2 is ordered from GMPARTSDIRECT. I'll do a final update after it gets here and I get it in, assuming that fixes it.

Thanks again!

Zander916

UPDATE:

The AFR's stayed normal all this week. The O2 sensor came in Tuesday and I planned on changing it out today.
Last night after work the car didn't want to start. It cranked for about 10 seconds and then fired up. A few seconds later, the MIL went out. I went to the gym. After that, it started normal and the MIL was still gone.

Weiiiiiiird.... but I'll take it.