Warmup AFR - "STFT Closed Loop" vs. Real Closed Loop... Why is there a difference?

[10_SS]

Today I started the LS3 Camaro to see if a spare ECM swap worked ok.. Coolant temp was 23F, and at that temp the "Closed Loop vs. Startup Coolant Temp" table says not to enter "Closed Loop" until 150F coolant temp... Also, the "Closed Loop" Delay timer is set for ~57 seconds at this coolant temp... OK, fine.

I start up no problem, runs great.. I see the 02's start swinging around 54F coolant temps which is the Closed Loop 57 second delay, and STFT is around -20%! (? my Closed Loop table says enter at 150F when starting around 20F).. also see it's asking for ~12.0AFR... with coolant temps now around 100F.. then I realized I forgot to connect my Wideband plug... so I connect it, LTFT are 0.0, but STFT is in some sort of closed loop and the Wideband AFR's fairly tight and averaging ~14.7AFR, but still the ECU is commanding ~12.0AFR.. this AFR difference just so happens to be the ~20% from the STFT correction.. and coolant temp is below the "Closed Loop temp" Also the Closed Loop PID is ON... So I realize there is an Initial "STFT Closed Loop" then later a "LTFT Enable"... ok.

Then, once coolant temp reaches 150F, LTFT ENABLE kicks into action (But this table is called just 'Closed Loop'... not under the LTFT Enable section), and things stabilize pretty quick around -4 to -8% LTFT... STFT now are normal, swining +/- a few %...

So, since this took me so long to figure out... my question is: Why is the LTFT ENABLE setting actually under the STFT Closed loop settings? AND if the ECU is commanding something like 12.0AFR, and your not at your "Closed Loop" coolant enable temp listed in just the "CLOSED LOOP" area but you are in the STFT Closed loop region... the STFT are able to apply that much correction to make it hold 14.7AFR... why does the ECU say it's commanding that rich open loop AFR when it's not?? I don't need to change anything.. just curious where the settings are like this.....

AFR Warmup ClosedLoop.PNG


So from all of this, I basically see these settings affecting the STFT and LTFT temps/timers... But the two different types of "Closed Loop" is not mentioned, and really confusing.. anybody know why it's like this?
ClosedLoop_Timers.PNG

[hjtrbo]

Bump

AND if the ECU is commanding something like 12.0AFR, and your not at your "Closed Loop" coolant enable temp listed in just the "CLOSED LOOP" area but you are in the STFT Closed loop region... the STFT are able to apply that much correction to make it hold 14.7AFR... why does the ECU say it's commanding that rich open loop AFR when it's not??

I have the same question. What is the point of having a closed loop delay if it is already really in pseudo STFT closed loop?

Am I right in thinking I can just kill the O2 readiness test for lower ECT values to keep it in O/L for that first part of the warm up cycle?

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[hjtrbo]

Just wanted to link these 2 threads together as I managed to find a way around it. See this post

https://forum.hptuners.com/showthrea...l=1#post631701