OL drops into CL temporarily...

[dc_justin]

I had a couple of wierd occurances for me today. In the process of AutoVE'ing a 2 bar custom OS. I've disconnected the bank 2 front O2 sensor and have my LC-1 installed there for the time being.
Driving along today, just in cruise cells, all of a sudden the truck felt like it dropped half into DFCO. Checked the log and the wideband went very very lean and the left bank started to switch like it was in closed loop.
Bank 2 sensor went from reading a default 440mv to reading over 1v, causing the pcm to pull all fuel from that bank.

Closed loop temp enable is set to max temp. LTFTs are disabled, STFT Idle Enable is disabled, etc, etc. OL tune has worked perfectly outside of this (other than trying to get the VE IAT multiplier nailed down for the metal magnacharger intake manifold)
This happened twice today, both times on the second run cycle after a re-flash, so the CEL was on in both situations... Any ideas? I've posted up a screenshot of the situation...

[Tordne]

I'm gunna take a guess and say that you probably (through interpolation between cells) ended up commanding 14.63 (or 1.00 EQ). In this situation the Custom OS goes into Semi-Open Loop and trimming occurs.

[dc_justin]

You can see my commanded AFR there in the lower right corner of 14.58:1 though. And it has only occured on the second start after a re-flash. Drove for 3 hours day before yesterday without it dropping into CL...

[Tordne]

I wonder if that is close enough to be considered an EQ of 1.0 thought, that is the units the PCM uses.

[dc_justin]

You'd think so, but my log file is over 30K frames :Eyecrazy: and the vast majority of it is commanding 14.58, but only about 300 frames have that issue... :nixweiss:

Log file from 2 days earlier on the first start since re-flash has 83104 frames and no issues.

[TAQuickness]

Assuming you're using the PID's in the AutoVE tutorial, what fuel trim cell where you in when that happened?

[dc_justin]

Nope, I haven't monitored FTC Cell in many moons now...

[joecar]

If your LC-1 is riding in the B2S1 location, then it's WB output (very lean) disagrees with it's NB output (rich)...

Which of these outputs is correct...?

Is this what I am seeing from your post...?

[dc_justin]

If your LC-1 is riding in the B2S1 location, then it's WB output (very lean) disagrees with it's NB output (rich)...

Which of these outputs is correct...?

Is this what I am seeing from your post...?

NB is disconnected, so input from it is completely irrelevant... which is why the PCM reaction is so interesting... B2S1 has no sensor attached and after running at ~ 0.45V for a long period of time it switches to 1v+...

And I've done the open loop thing a few times before, so I'm no stanger to it, and it's definitley something new to me.

BTW, Joecar, I'll be in your neck of the woods around noon tomorrow. If you want to meet up for a few minute and share war stories, I'd be more than willing to meet another EFI Live user.

[joecar]

Ok, I'll be up late in the morning, say noon, I'm having yet another late night.

Edit: pm sent. :cheers: