Commanded AFR Glitch 16.00 for no reason

[Captsteve]

My Commanded AFR goes to 16.00 at cruise from time to time. I believe my AFR tables are correct. I need someone to take a sec and look at my files to see if I have done something wrong or if I have an issue I'm not aware of. Should be 14.7 at cruise, when in PE AFR drops as requested.
Engine is Stock LQ4 except for Headers, cold air, and a couple things deleted for swap.
3rd scan with trans tuning 08252019.hplfirst complete tune with torque management changes with trans changes 2006 LQ4.hpttuning layout.Channels.xml

[5FDP]

It's not a glitch, it's a cat test.

You will also notice that the commanded AFR goes to that 16.00, then drops to 13.XX right after and back to stoich.

This happens when you remove the rear o2 sensors from the vehicle. HP Tuner itself can not disable this test. Everytime I have run into this issue you have to plug the rear o2 sensors back into the harness so the circuits are not left open and just disable all the codes.

Must be an older log compared to the tune file. You do go full throttle and commanded AFR stays at 14.68 but the tune shows it should be dropping to around 12.0.

[Captsteve]

Well that?s unfortunate. I made the harness and removed the rear O2 wires from it. Any other way around this issue?
As for the WOT I haven?t made it to that point in tuning yet. So I didn?t notice it yet. As for the log it is for that tune I think.

[5FDP]

No way around it when using HP Tuners. I think EFI live can disable the test but not this software. The P59 computer is like the only one that does this. The early P01 don't have this issue nor do the newer computers.

[Captsteve]

I appreciate your help. One more question will an 0411 ECM work with my 06’ engine 4L80 wire harness and throttle pedal? Also is there any benefit in having the rear O2 in the exhaust, or just laying around the engine compartment?

[Captsteve]

The reason I ask is I am planning on adding a LSA to the 6.0 in the winter.

[5FDP]

The older could work on the engine/transmission but not with your harness or pedal assembly stuff. We are talking two different generations of computers. One is a red/blue connector and the other a blue/green which are wired completely different. The 06 pedal/tac/app wouldn't communicate with the older computer.

You could get a 99-02 wire harness/computer and switch to drive by cable but that's a ton of work.

There is no benefit of having rear o2 sensors, they aren't required. You'll just have this issue that will be trouble some to work around when the circuits are not there.

[Captsteve]

Looks like I’m going to wire in some rear O2’s. Thanks aging.

[3strokeEngine]

No way around it when using HP Tuners. I think EFI live can disable the test but not this software. The P59 computer is like the only one that does this. The early P01 don't have this issue nor do the newer computers.

Another case of HPtuners dropping the ball and leaving out tables, i guess thats why EFI live is more expensive, you get what you pay for! And apparently 650$ for HPtuners isnt enough.

[5FDP]

If you want to talk money, it's only $400 if you got the MPVI2 plus the 2 credits for that computer. This problem is only with one style of computer on the LS V8 engines that I know of, and for most it's not an issue because it's not a swap harness that's been cut apart. I still think that for the money you are getting a hell of a bargain for what this thing can do.

It's up the user if they want more features and that costs more money.

[mbray01]

I'm pretty certain its a hard code issue. I know a couple prominent efilive tuners, and to my knowledge, there isn't a work around with either software. Honestly, its not causing any issues, you shouldn't notice any different feel when it happens(unless fueling is way off to begin with). Let it do its thing. Don't over think this. Don't fix what isn't broken definitely applies here

[Captsteve]

Well it’s commanding 16.00 AFR at cruise speed. Is that not an issue? Especially when I plan on installing a LSA this winter.
What does lean cruise command afr wise?

[5FDP]

Lean/cruise is about that 15-16 but it's not just that because it also goes rich on the other half of the test down to like 13.2.

I don't think this test is carried out in open loop for all of your fuel tuning with a wideband but it's something I didn't like dealing with when going back to closed loop.

[Captsteve]

When In open loop I didn’t see it. That’s why I thought I had an issue when I tested the tune.

[mbray01]

Going 16.0 isnt hurting anything, this is only done while cruising. If there was a possibility of it hurting parts, gm wouldn't be doing it. It doesnt do it under wot so having a blower will not affect that in any way