Bad A/F at idle

FlashPro questions & answers specific to the 2006-2011 Americas Civic Si
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abarry94
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Joined: Wed Apr 11, 2018 9:12 am

Bad A/F at idle

Post by abarry94 »

I have had my 07 civic si tuned with a injen cai for about a year , ive been having significantly bad fuel mileage lately. Ive been tackling a few issues from timing/vtc gear to new cone filter, oil change, and new mass air flow. Im throwing a knock sensor code due to breaking the connector while changing the starter. That is the only code I show and my car seems like its running on 3 cylinders or has an exhaust/vaccum leak its that delayed. I was wondering if I uploaded a datalog if somebody would be able to look at it and point me in the right direction.

Thank you in advance.
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Spunkster
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Location: Hondata

Re: Bad A/F at idle

Post by Spunkster »

Start by fixing anything that is generating an error code, if it continues to run improperly after all codes are resolved then start looking at other things.
abarry94
Posts: 3
Joined: Wed Apr 11, 2018 9:12 am

Re: Bad A/F at idle

Post by abarry94 »

So after work last night i decided to finally fix my broken knock sensor, clear my fcan malfunction code vsa to ecu ( canadain si) and then also replaced my intake cone since it was dirty. So now i cleared all cel's and took the car for a drive running a basemap for just a injen cai. Now my cars a/f was 29:1 idle which i read is normal when no throttle is given if im correct. So i took the car for a drive through town still felt lag or delay. vtec was quiet. and once on highway i checked my a/f ratio and knock count. so Knock #1 showed maybe 1 or 2 knock #2 30 knocks from a 5-10 min drive. knock #3 2 or 3 and knock #4 1 or 2. Did my daily drive to work and checked the datalog and seen 150 in knock #2 today and 30 in knock #3. #1 and #4 seemed normal. No idea where to go from here.
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Spunkster
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Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: Bad A/F at idle

Post by Spunkster »

It should be running at about 14.7:1 at idle. If it is reading that lean you may have a bad o2 sensor.
abarry94
Posts: 3
Joined: Wed Apr 11, 2018 9:12 am

Re: Bad A/F at idle

Post by abarry94 »

I think its either the upstream o2 sensor because I started throwing a system too lean bank 1 code on the way home after work. Was narrowing it down between vaccum leak and 02 sensor bad. Ive been trying to read my data logs to understand whats running so poorly to effect my A/F that much but pretty new to datalogs.
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