Why is my PCM setting the wrong Fuel Trim Cells?
03-18-2005, 12:59 AM
#1
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Why is my PCM setting the wrong Fuel Trim Cells? I was reviewing some past HP Tuner scan logs and was watching the FTC to see were I was hitting some of these cells. Well I found that my PCM is putting me into cell 22 a lot and from my understanding WOT should be cells 22 and 15. As you can see from the pics below it's putting me into Cell22 just putting down the highway and sometimes even at IDLE. What is causing this? Any help would be greatly appreciated and if someone wants to see the log file just give me your email address and I'd be more than happy to email it to you. Thanks again!
03-18-2005, 06:58 PM
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Originally Posted by P Mack
Have you turned off cat overtemp protection?
Not yet! This is the first time I've heard that it should be turned off? So what effect does the Cat Overtemp protection have and how will it react when set to the off position? Maybe this also has something to do with the FTC 0 and the fact on every log I'm showing at least a small percentage of hits in FTC 0 and LTFT & STFT bottom out at -100?
Thanks for the help P Mack!
03-18-2005, 07:09 PM
#4
Well something is throwing you into open loop, which is cell 22 for anything but idle. The only 4 things i can think of that will put you in open loop is wide open throttle, cold start, engine overheating, and cat overtemp protection. Cat overtemp just means the pcm thinks the cats are overheating so it takes you out of closed loop and richens the mixture to cool them down. Pretty much everyone turns it off, even with cats.
03-18-2005, 07:15 PM
#5
FTC = 0 is a normal closed loop cell for rpm<800 and map<35. You won't see it very often but it's nothing to be worried about, unless there's something i don't know about. As for the -100% fuel trims, i've never seen that before. Could be a cable hickup maybe.
03-18-2005, 07:58 PM
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Well **** I just checked my last BIN file and CAT over temp is already set to Off and all the variables on that page are Greyed out and blank!
Would it be posible that something is very screwy with my MAP sensor or readings so that it believes i'm WOT? The reson I'm asking is this:
I noticed under the Power Enrich tab PE Enabled has 3 trigers (if i'm reading it right). One triger is mode delay rpm =2100 Map Hysteresis = 6 and Map = 15. I've gone back through several scans were I had done a little WOT runs and found that my MAP wasn't ever reaching 15 much less going beyond it?
As for the -100 every time I see anything in the FTC 0 cell it is always -100.
Would it be posible that something is very screwy with my MAP sensor or readings so that it believes i'm WOT? The reson I'm asking is this:
I noticed under the Power Enrich tab PE Enabled has 3 trigers (if i'm reading it right). One triger is mode delay rpm =2100 Map Hysteresis = 6 and Map = 15. I've gone back through several scans were I had done a little WOT runs and found that my MAP wasn't ever reaching 15 much less going beyond it?
As for the -100 every time I see anything in the FTC 0 cell it is always -100.
