Fuel leans way out when closed loop turns on, then normalizes

[AdsoYo]

This weekend was very cold where I live, around 20 degrees. I took the opportunity to tune areas of the open loop table I haven't been able to hit yet. I noticed when the car transitions from open to closed loop, the fuel leans way out for about 20 seconds then reels itself back to commanded AFR. At first I thought it's because I was commanding a too-rich mixture of ~13:1 at the transition point of 91 degrees coolant temp and that was throwing it off somehow. I went back and leaned it to 13.3:1 and the transition leaned out even more! Is there a table somewhere I can adjust to prevent this crazy lean swing?

Here's the log running my original open loop table where the afr is 13:1 when it goes into closed loop. You can see it leans out to 15.45 before settling down 20 seconds later.
richer.jpg

And here's the log where I leaned it out to 13.3:1. You can see it leaned out to 16, maybe more. My wideband only goes to 16. You can also see it's running leaner than commanded during the whole log, not sure why. I only changed the open loop table.
leaner.jpg

[horsepowerguru427]

Can you post the log file as well, please?

[SiriusC1024]

Exhaust gas is probably cooling the sensor. Increase CL enables. Something like this:
CL enable.png

[AdsoYo]

Can you post the log file as well, please?

I will tonight, working til 10 pacific time.

Exhaust gas is probably cooling the sensor. Increase CL enables. Something like this:
CL enable.png

I thought about increasing enable temps but stock has it at 91. Does LS1 vs LS3 and long tubes make that much of a difference? Would the base idle airflow table affect this at all?

[SiriusC1024]

Makes a lot of difference. The gas is traveling a longer distance through cold pipes than factory. Raise the enables. This makes more run-time on the engine per IAT (ambient relation) and gets exhaust system up to temp.

[AdsoYo]

Makes a lot of difference. The gas is traveling a longer distance through cold pipes than factory. Raise the enables. This makes more run-time on the engine per IAT (ambient relation) and gets exhaust system up to temp.

I'll give it a try thanks!

[edcmat-l1]

Putting some catalyst heating timing back in it will help some also. Help get the headers up to temp quicker in the cold.

[horsepowerguru427]

Exhaust gas is probably cooling the sensor. Increase CL enables. Something like this:
CL enable.png

Hmmm, this crossed my mind as well. I was hoping to see a log just to make sure nothing popped out at me though.

[SiriusC1024]

Yeah I get it. Sometimes you give a simple answer that should work, and they come back saying it didn't fix it because something else was off.

[edcmat-l1]

Yeah I get it. Sometimes you give a simple answer that should work, and they come back saying it didn't fix it because something else was off.

My favorite line, "Nah that ain't it!"

[SiriusC1024]

Those are the worst.

[AdsoYo]

The log files have been added to the original post.