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View Full Version : what drives commanded wot afr ratio



steve40
November 19th, 2016, 08:05 AM
around frame 430 i did a pull on the car.....once you get to frame 495ish, the commanded afr drops down to 11.7 and stays there.

looking thru the tune i wasn't able to see where 11.70 is commanded for wot other than in the piston protection table, but looking at the values, i don't think the car should be going into piston protection...is there a way to check that?

i attached a pic of the pull as well

joecar
November 19th, 2016, 12:24 PM
The richest current cell in the currently active fuel tables/modes...

at WOT these fuel tables/mode may be active:
- PE Fuel table B3618,
- COTP (AFR 11.7),
- PPM,
- EPM,
- OL Fuel table B3605 (if running OL),

the PCM selects the richest cell at the current operating point in those tables.

joecar
November 19th, 2016, 12:28 PM
So it's probably COTP.

steve40
November 19th, 2016, 03:23 PM
is that cat over temp protection?

joecar
November 19th, 2016, 06:33 PM
Yes, correct.

steve40
November 20th, 2016, 08:44 AM
is cotp predetermined at 11.7:1? i wasn't able to find a table with that specific ratio other than b3659 commanded fuel when in piston protection mode

joecar
November 20th, 2016, 05:12 PM
Yes, there is no visible COTP fueling table... but it is empirically known to be AFR 11.7.