Running Rich w/ skunk 2 cai

2012+ US/Canadian Civic Si / 2013+ ILX
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GGRaiderr
Posts: 2
Joined: Thu Oct 22, 2020 3:32 pm

Running Rich w/ skunk 2 cai

Post by GGRaiderr »

Hi everyone, i have a 14 si and all i have done to it is put in a skunk 2 cai, I plan on getting a catback exhaust when i can afford it, with a tune of course, but as of right now, the intake i installed is causing my car to throw up as emissions engine light every 200 miles or so. Is there anything i can do to fix this for the time being with a simple tune that will last me until i get the money to tune it with the exhaust? i feel like going back to stock is probably the easiest way, but considering i took a new job just recently and dont necessarily have the time and/or want to take the cai off and go stock again, im looking for an alternative. Please let me know if there is anybody that can help or anything else i can do for the time being. I appreciate any and all help in advance!
BlackAndChrome
Posts: 8
Joined: Thu Aug 31, 2017 5:42 pm

Re: Running Rich w/ skunk 2 cai

Post by BlackAndChrome »

Disclaimer that I'm not a pro by *any* means just a novice cheapskate trying to figure this out enough for my needs, I don't even touch fuel or timing tables. I might be able to point you in the right direction though. It is your responsibility to take this with a grain of salt, follow safe tuning procedures, and understanding that if you poke around in the tune you are the one responsible for damages.

With an aftermarket CAI your MAF sensor is unlikely to be calibrated correctly, and I'm assuming you are still on a factory MAF tune or Hondata Reflash. Not sure what the emissions code is saying exactly, whether that's the downstream O2 sensor indicating that the CAT is not doing it's job or that the fuel trims are outside of limits.

I'd start here. https://www.hondata.com/help/flashpro/i ... s_flow.htm

And specifically follow the "Tuning AFM Flow" link that takes you here. https://www.hondata.com/help/flashpro/i ... m_flow.htm

One thing that tripped me up when I first started playing with my Flashpro is that the process above does not say anything about L.trim, which changes with the average S.trim to bring it closer to zero. S.trim does not have an effect on Open Loop but L.trim does (that's my understanding someone please correct if wrong). Plot both the L trim and S trim to help indicated any big changes that need to be made to the AFM calibration. Once you get within ~20% total trim for a mixed drive you can set "long term fuel trim" min/max to zero in the closed loop section of the calibration and purely follow the second part of that guide using S.trim to tune AFM. Try to keep your curve smooth. I've been using an excel sheet to make adjustments, plot a 3rd order polynomial line of best fit, then use that equation to fill the data points back in smoothly. I don't really get any closed loop numbers past 3.2v so I've been doing a WOT pull from 4k to redline and comparing the A/F CMD to A/F at any given AFM.V then adjusting numbers above 3.2v with that. I then smooth with the excel sheet, and using the line of best fit to project the AFM calibration up to 5v (not that it could ever be reached). Remember to re-enable L.trim.

If that's daunting just datalog some mixed driving and start by seeing what the car is doing, finding the problem, then making motions to solve it.

-Nick
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