What Causes Cat Over Temp (COT)
09-17-2003, 08:43 AM
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Re: What Causes Cat Over Temp (COT) If the computer detects a lean situation it starts dumping fuel to cool the cats down and protect them from overheating. Usually one of the first steps in tuning is to turn it off especially is you dont have cats
09-17-2003, 09:16 AM
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Re: What Causes Cat Over Temp (COT) I've wondered about this, my question is whether
if a car is tuned right, not going lean, will COT
trigger be prevented even at extended periods of
high RPM, high output? What is the O2 voltage
threshold or A/F threshold for COT to stay off?
if a car is tuned right, not going lean, will COT
trigger be prevented even at extended periods of
high RPM, high output? What is the O2 voltage
threshold or A/F threshold for COT to stay off?
09-17-2003, 09:53 AM
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Re: What Causes Cat Over Temp (COT) I am not sure about all the information regarding thresholds and when it kicks in. If the car is tunned appropriately a lean condition shouldnt exist (semi lean maybe)and i am not sure when exactly it starts to kick in but usually anytime COT was discussed it was turned off because it can indiscriminantly add fuel causing the mixture to go rich and kill power.
Usually what happens is the tuner/user wants to lean out the A/F ratio and starts making changes but because COT intervenes it looks as though nothing is changing. Hope this help
Usually what happens is the tuner/user wants to lean out the A/F ratio and starts making changes but because COT intervenes it looks as though nothing is changing. Hope this help
09-17-2003, 03:30 PM
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Re: What Causes Cat Over Temp (COT) You will not be able to tune AFR lean enough for max power with COT not adjusted or disabled. My COT had to be disabled
to get to anywhere from 12.8 to 13.1:1. Don't know what temp. it kicks in.
to get to anywhere from 12.8 to 13.1:1. Don't know what temp. it kicks in.
09-18-2003, 07:53 AM
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Re: What Causes Cat Over Temp (COT) I don't think COT has any direct way of knowing
the cat temps, it just predicts based on some
combo of O2 mV, RPM, time-at-output, and maybe
some engine load params.
Do you know the trigger threshold for AFR (or
O2 mV)? I'd run 12.5:1 up top if it kept me from
falling to 10:1 after 30 seconds of WOT....
the cat temps, it just predicts based on some
combo of O2 mV, RPM, time-at-output, and maybe
some engine load params.
Do you know the trigger threshold for AFR (or
O2 mV)? I'd run 12.5:1 up top if it kept me from
falling to 10:1 after 30 seconds of WOT....
