fuel trim cell pictures
fuel trim cell pictures A couple people have asked me about fuel trim cells so I thought i'd post up these pictures that have helped me many times in the past.
Notes:
- Some years of cars (like 2000) will have different fuel trim cell rpm boundaries. This was probably done to make sure all rpm ranges learned trims as fast as possible. I changed mine to the way the picture is.
- The term "cold idle" in the second picture (ftc 20) should really be called "open loop idle" since it can be used on hot starts as well; it's used when the o2's are cold and haven't started oscillating yet.
- FTC 22 should really be called "open loop - off idle" because it's used for all open loop driving except idling, including but not limited to WOT.
Feel free to make corrections.
Notes:
- Some years of cars (like 2000) will have different fuel trim cell rpm boundaries. This was probably done to make sure all rpm ranges learned trims as fast as possible. I changed mine to the way the picture is.
- The term "cold idle" in the second picture (ftc 20) should really be called "open loop idle" since it can be used on hot starts as well; it's used when the o2's are cold and haven't started oscillating yet.
- FTC 22 should really be called "open loop - off idle" because it's used for all open loop driving except idling, including but not limited to WOT.
Feel free to make corrections.
Last edited by P Mack; Jul 31, 2005 at 01:24 PM.
ok so remember my problem at 2:38 (min:sec) logged today to find out thats when i switch from ftc 20 to ftc 19, my o2s DO oscillate up until that area. it would be nice if we coudl figure out the whys and hows of this
Originally Posted by P Mack
- The term "cold idle" in the second picture (ftc 20) should really be called "open loop idle" since it can be used on hot starts as well; it's used when the o2's are cold and haven't started oscillating yet.
Yeah, I don't know how exactly what conditions have to be met (besides ect), maybe they have to oscillate for a certain amount of time or something. That's another good question for the software guys.
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also, i got an evap code a while back, 2 times. this could be caused by a evap purge valve purging off. i wonder if these conditions are not normal, maybe that could be why mine stays in 20 during open loop. but the only way to tell is get someone that knows more about this to come in here and answer some questions, which we will have a hard time getting i bet
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Originally Posted by 405HP_Z06
I very often wonder the same thing. I've got to scare up some cash for EFILive!!!!!!
Bill
