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Old 06-29-2018, 11:10 PM   #17 (permalink)
Cyborg ECU
California98Civic's Avatar
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,297

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
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Not solved

On fifth drive cycle since fuel trim fix, the P0420 came back today. Diagnosis testing done. I have an inefficient CAT. I will clean it to see if that clears the code. I'll post those results in my CAT restoration thread.

At least this process taught me new testing techniques and revealed a simple cause for the bad fuel trims.
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.

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me and my metro (06-30-2018)