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California98Civic · 02-01-2015, 05:38 PM

So, ever since installing the new WAI and getting markedly higher 40-50 degrees over ambient temps on the intake sensor, I have noticed long term fuel trim greatly leaned-out, as in this photo. I also think I can feel less power in certain routine situations. Oddly, conventional wisdom here has been that the ECU will keep stoich and that gains come from reduced pumping losses. I still think the pumping losses idea makes sense, but my UG is telling me I am running far leaner than I used to. Normally, this long term fuel trim would read +0.78, now it generally reads -6.2 and leaner.

Why, do you think?

02-01-2015, 05:38 PM	#236 (permalink)
California98Civic Cyborg ECU Join Date: Mar 2011 Location: Coastal Southern California Posts: 6,299 Black and Green - '98 Honda Civic DX Coupe Team Honda 90 day: 66.42 mpg (US) Black and Red - '00 Nashbar Custom built eBike 90 day: 3671.43 mpg (US) Thanks: 2,373 Thanked 2,174 Times in 1,470 Posts	Update: WAI and AFR So, ever since installing the new WAI and getting markedly higher 40-50 degrees over ambient temps on the intake sensor, I have noticed long term fuel trim greatly leaned-out, as in this photo. I also think I can feel less power in certain routine situations. Oddly, conventional wisdom here has been that the ECU will keep stoich and that gains come from reduced pumping losses. I still think the pumping losses idea makes sense, but my UG is telling me I am running far leaner than I used to. Normally, this long term fuel trim would read +0.78, now it generally reads -6.2 and leaner. Why, do you think? Attached Thumbnails __________________ See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.