Info Sharing: O2 Sensor issue resolved

Evidently, older style OEM O2 sensors make a difference. I've been fighting STF issues on cold start for months. On a cold start up (tune is closed loop), both STF drop to .60 lamda for 45 seconds before the PCM intervenes for which they recover at 1.40 before slowly recorrecting to 1.0. Basically, I couldn't drive the car for about 3 minutes on initial start up without bucking and sometimes stalling. Smoke testing, gasket replacements, and many hours with a very patient tuner (thanks BJ, excellent tuning service!) are just a fraction of steps done. Followed a suggestion by JDM and ditched the newer version of OEM O2 sensors (GU2Z9G444A) and replaced one bank with the older style (5C5Z-9F472-AA - green in color) for testing and....theory proven. Using the older style O2 sensor rid me of the issue (see attached for datalog comparison). Blue line is the older sensor displayed and operating as it should. From what I'm told The newer version 02 Sensors are a universal part now for all older Ford applications. However, they are actually a monitor not a sensor and therefore, don’t read properly.

Bottom line, after months of frustration, my issue is solved and thought I'd share in case anyone else has experienced this issue.

Many thanks to BJ for excellent tuning service and JDM for the helpful suggestion.

Awesome that worked for u and thanks for sharing the knowledge. I do wonder how things work for those with o2 sesnsors tuned out?

DaFreak said:

Awesome that worked for u and thanks for sharing the knowledge. I do wonder how things work for those with o2 sesnsors tuned out?

Click to expand...

While in the tuning process, we switched from OL to CL with the same tune. In OL, the issue was non-existent whereas going to CL and the issue came back. Basically in OL, adaptives (O2 sensors) are turned off so the motor relies on the fuel tables and ignores the O2 sensors. I'm sure a professional tuner could describe it better, I was trying to keep up as described to me with all the note taking!

Well, even though I have a 04 Cobra, that would explain why I had the issues I had when I ordered a set of O2 sensors for my car. They showed a photo of the old style and I got a set that looked just like an off the shelf set of Bosch sensors from a parts store only with a Ford part number. I ditched them for a set of NTK sensors.
Thanks for posting this!


Sent from my iPhone using Tapatalk

SVTdreamin04 said:

Well, even though I have a 04 Cobra, that would explain why I had the issues I had when I ordered a set of O2 sensors for my car. They showed a photo of the old style and I got a set that looked just like an off the shelf set of Bosch sensors from a parts store only with a Ford part number. I ditched them for a set of NTK sensors.
Thanks for posting this!


Sent from my iPhone using Tapatalk

Click to expand...

I’m also running the NTK sensors on a recommendation from Van. No issues with them and they’ve lasted much longer with my LTs than the OEM sensors.

Good to know NTK is recommended. It's what I swapped in when one pegged lean. I put them in both front banks while I was cursing getting them out.

Well, cant find the old Ford OEM sensors. I've only got one. Anyone have a part number for the NTK or Denso?

NGK NTK 24325. They’re pretty cheap from Walmart right now at $98 a piece shipped. Not a bad deal, even better than Amazon.

RRB is that the part number for the wide band O2s, because Sielmo has a 2010.

Correct, NGK NTK 24325 is for the wide band up streams. Looks like NTK 22060 is the one for 2010 but I'd double check that.

Catmonkey said:

RRB is that the part number for the wide band O2s, because Sielmo has a 2010.

Click to expand...

That is the wideband. Sorry Sielmo, didn’t realize you had a 2010! That's such an oddball year, it looks like all the other 11+ models, but has the old engine in it....

RBB said:

That is the wideband. Sorry Sielmo, didn’t realize you had a 2010! That's such an oddball year, it looks like all the other 11+ models, but has the old engine in it....

Click to expand...

Thanks for the correction...I think I found an older OEM on Ebay so we'll see when it shows up. NTK is my back up.

Sent from my SM-G930V using Tapatalk

Sielmo said:

While in the tuning process, we switched from OL to CL with the same tune. In OL, the issue was non-existent whereas going to CL and the issue came back. Basically in OL, adaptives (O2 sensors) are turned off so the motor relies on the fuel tables and ignores the O2 sensors. I'm sure a professional tuner could describe it better, I was trying to keep up as described to me with all the note taking!

Click to expand...

Pretty good notes buddy.

It was obvious that something was amiss, so tuning it in open loop via Terry's wideband would take everything else out of the equation. It allowed for appropriate fueling and performance then we could let the fuel trims do their job back in closed loop.

Nope.

Glad to hear JDM shared the facts on Ford's "new" replacement.

At some point I will snag a stock narrow band car and send them a set of the new sensors, have them installed and log their performance.

I find it hard to imagine that these were not fully vetted but weirder things have happened.

Bj

Sent from my SM-N950U using Tapatalk

1 size fits all doesnt really work with high performance car with critical fueling needs. Sielmo, Im glad you got it sorted man.

NTK's parent company is NGK. If Ford ever dumps 2011+ sensors like that, NTK will easily get the nod.

VNMOUS1 said:

Pretty good notes buddy.

It was obvious that something was amiss, so tuning it in open loop via Terry's wideband would take everything else out of the equation. It allowed for appropriate fueling and performance then we could let the fuel trims do their job back in closed loop.

Nope.

Glad to hear JDM shared the facts on Ford's "new" replacement.

At some point I will snag a stock narrow band car and send them a set of the new sensors, have them installed and log their performance.

I find it hard to imagine that these were not fully vetted but weirder things have happened.

Bj

Sent from my SM-N950U using Tapatalk

Click to expand...

Thanks Bj, for your thorough help... I'd never get this from any other tuner!

Sent from my SM-G930V using Tapatalk