Issues turning closed loop back on

[BrodyO]

Hi All,

I'm at the point in my fuel map now that I'd like to turn the 02 sensors back on and make the final, smaller adjustments through the LTFT. I'm having some issues when turning these back on. I'm assuming it's one of the two things: The parameters in the calibration for turning the 02's back on is incorrect (I don't have my old N/A calibration to reference, I used a calibration from a 2009 Colorado 5.3 which is what I use for 02 sensors), I have bad sensor data (it looks like my 02 sensor signal goes from reading down to near 0, on both sensors, constantly).

The sensors I used are right at the end of my down pipe. The sensors are used denso 234-4337. They've been on the shelf for a couple years but they were used in this truck for a couple thousand miles and worked great when pulled to go turbo.

When driving with the attached calibration, the wideband AFR readout is going all over the place, backfiring when getting into the throttle etc. Something isn't happy. When I swap over to the same calibration with open loop, it runs good.

Last file is the reference stock 2009 calibration from the tune repository.
Please let me know your thoughts. Thanks!
Colorado_7875_VVE_2Bar_SEPpro1000cc_Rev5_ClosedLoop.hpt
LSColorado_e67_4bar_flex_SD_1000ProSeries_CL Attempt _04122024.hpl
1302962323.hpt

[Alvin]

the o2's look healthy but the fuel trims are split big time.

I suspect the right o2 sensor has been plugged into the left sensor spot on the harness. It happens way more often than you'd expect.

Unplug which ever sensor you can get to easiest. It should read 450mv unplugged. Make sure that B1S1 is drivers side and B2S1 is passenger side.

[BrodyO]

the o2's look healthy but the fuel trims are split big time.

I suspect the right o2 sensor has been plugged into the left sensor spot on the harness. It happens way more often than you'd expect.

Unplug which ever sensor you can get to easiest. It should read 450mv unplugged. Make sure that B1S1 is drivers side and B2S1 is passenger side.

I will do that. I have a single exhaust now with the turbocharger so both narrowband 02 sensors are in the same pipe, a couple inches from each other, clocked slightly different. I could just run one of those sensors if that was possible in the calibration. Essentially now they're just acting like a redundant sensor setup.

[edcmat-l1]

The sensors I used are right at the end of my down pipe.

Can you be more specific on this? How close to open air are the O2 sensors?

Not a fan of 2 sensors in the same pipe. It'll never figure out the bank to bank fueling.

[BrodyO]

Can you be more specific on this? How close to open air are the O2 sensors?

Not a fan of 2 sensors in the same pipe. It'll never figure out the bank to bank fueling.

They are a long ways from open air, probably 6 feet, the truck has a full exhaust out the rear. The sensors are actually very close in the pipe to where they would be in the factory location. They are between 2-3 feet from the turbo outlet. I don't really have an option not to mount them in the same pipe unless I would've put them in the up pipes under the hood.

[Alvin]

I will do that. I have a single exhaust now with the turbocharger so both narrowband 02 sensors are in the same pipe, a couple inches from each other, clocked slightly different. I could just run one of those sensors if that was possible in the calibration. Essentially now they're just acting like a redundant sensor setup.

That is the issue. You can't put them pre turbo? Unless its a full out race setup the 02's will be OK with the heat.

[BrodyO]

That is the issue. You can't put them pre turbo? Unless its a full out race setup the 02's will be OK with the heat.

It is possible but it wouldn't package well and force me to un-do a fair amount of work. I understand it's certainly more ideal to be bank-bank but I guess I still don't understand why it would be running so crappy with the setup as-is. I mean, right now the whole fuel map is based off readings from the single wideband 02 that's in the downpipe as well (about 10" from the turbo) and it runs much better than the narrowbands trying to trim.

So, if my sensors are plugged in correctly (which they kind of have to be, they should both be reading the same regardless in this setup), then what are my options? Am I able to run my trims off a single narrowband? If not, any ideas why I'd be trimming so differently in one bank than the other?

[BrodyO]

What I don't understand is why my 02 sensor output between the two sensors is nearly line over line identical but the LTFT's between banks are wildly different as mentioned above. Thoughts?

[blindsquirrel]

Have you tried changing the Injector Bank Select to all 1's, or all 0's? AFAIK all that does is tell it which bank's sensor should be used for adding/subtracting fuel via trims.

[BrodyO]

I can give it a shot