conflict between WB & NB LTFT
04-12-2007, 09:20 PM
#1
conflict between WB & NB LTFT I install a PLX SM-AFR+DM-5 wide band and even hooked it up to my EFI Live and its reading 15.0 to 16.0 and my LTFT are -10 at cruse 60 mph at 2000 rpm .I have installed new corvette style NB O2's sensors the same time i installed the WB, and the WB & NB sensors are installed straight a cross from each other. So what would cause the WB to read lean and the NB to read rich . Can some one explain please
04-13-2007, 12:33 PM
#5
I have my EFI Live scan running and not in SD mode, just as a reader. the WB is independent, its only as a reader also , and the LTFTs are reading rich and the WB reading lean. and this is happening from idal to 4000 rpm, and from 4000 rpm up the WB goes rich 12.3 and the LTFTs goes to 0.0
04-14-2007, 09:42 AM
#6
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What are your NB O2s reading?
My guess is that they are locked somewhere above stoich and your PCM is pulling fuel in an attempt to get them to lean out. Since they are locked, your car ends up running leaner.
As for the behavior above 4K RPM, I'm guessing you are in PE mode and therefore do not use LTFTs, i.e. they zero out.
My guess is that they are locked somewhere above stoich and your PCM is pulling fuel in an attempt to get them to lean out. Since they are locked, your car ends up running leaner.
As for the behavior above 4K RPM, I'm guessing you are in PE mode and therefore do not use LTFTs, i.e. they zero out.
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04-15-2007, 02:31 PM
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Originally Posted by Randy WS6
the NB's are around -10.0 to -12.0 and the WB is a round +15.0 to +16.0
04-15-2007, 05:16 PM
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Originally Posted by Randy WS6
Im not running the NB from the WB system, The NB is from the stock sensors system, And the PLX-WB is independent from the system ,and both sensors was installed at the same time and directly across from each other.
Closed loop fueling is based off of feedback from your narrow band O2s. If you are having fueling issues, I would first verify my NBs against my WB and the LTFTs. One of them has to be off based on your symptons.
04-15-2007, 09:56 PM
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Originally Posted by Randy WS6
The NB is reading 14.6AFR and the ltft's -10.0 to -12.0 ,This is what is showing on my EFI Live logging, and the PLX WB is showing at the same time 15.0.to 16.0 AFR.
04-15-2007, 10:12 PM
#13
did you have a wb prior to the plx? any issues with it?
how/who did your tune for the 408. maybe something was wrong with the tune before you got the plx and didn't know it?? now you find out with the new wb?
if your wb is set up correctly.....
possibly your wb is reading afr at 15.0-16.0 because another table such as maf is being used besides the ve which uses ltft.
ve, maf, spark will need to be looked at among others that could be affecting your afr.
4k+ rpm, your probably in pe/maf table and 0 ltft is what you want to be.
*i don't know how to tune. just throwing this out for consideration.
how/who did your tune for the 408. maybe something was wrong with the tune before you got the plx and didn't know it?? now you find out with the new wb?
if your wb is set up correctly.....
possibly your wb is reading afr at 15.0-16.0 because another table such as maf is being used besides the ve which uses ltft.
ve, maf, spark will need to be looked at among others that could be affecting your afr.
4k+ rpm, your probably in pe/maf table and 0 ltft is what you want to be.
*i don't know how to tune. just throwing this out for consideration.
