Issues Passing Smog Test

Bruce Bartlow

Bruce Bartlow

Late apex everything
1,599
865
Sacramento, CA
Vehicle Model
Rented a C8 for a week (what a monster) ended up buying a TLX. Beautiful car inside and out. Killer stereo. Handles better than it should given its weight. Not my dream car, just a Honda Accord in a tux.
Body Style
Sedan with the backseat of a two-seater
Speaking of the 2012 Si... having major problems passing smog after a series of mods. Returning to stock hasn't worked. All of it somewhat strange, but one solution (perhaps) is an new ECU control unit, about $400, using the new computer for smog and the existing computer for operation.

Any thoughts, links, prior experience?

Much obliged!
 
Bruce Bartlow said:
Speaking of the 2012 Si... having major problems passing smog after a series of mods. Returning to stock hasn't worked. All of it somewhat strange, but one solution (perhaps) is an new ECU control unit, about $400, using the new computer for smog and the existing computer for operation.

Any thoughts, links, prior experience?

Much obliged!
Click to expand...
Did you mean to post this in another thread? The original user has a 2012 ex.

You’re having issues getting yours to pass emissions with the stock exhaust/downpipe?
 
webby said:
Did you mean to post this in another thread? The original user has a 2012 ex.

You’re having issues getting yours to pass emissions with the stock exhaust/downpipe?
Click to expand...
______
sorry, missed the EX part. So yes, wrong thread.

In terms of mods, full race dp with nvidia 300 exhaust, later CAI to help low end torque that was compromised by the first two. Overall it's working very well. But living here in CA doesn't help.
 
Moved thread so it'd make more sense....

Bruce Bartlow said:
major problems passing smog after a series of mods. Returning to stock hasn't worked.
Click to expand...
you tried to pass smog and failed with the oem exhaust/downpipe? Do you have any check engine lights when you went back to stock? Oem cat bad?
 
webby said:
Moved thread so it'd make more sense....


you tried to pass smog and failed with the oem exhaust/downpipe? Do you have any check engine lights when you went back to stock? Oem cat bad?
Click to expand...
thanks@webby

Here's the deal: Aftermarket downpipe, exhaust and CAI. Even when reverting back to stock map (using FP) still, all the "readiness monitors" failed to turn green. Eventually, I did get a check engine light. (The front o2 sensor is new, the other one is not) No matter what I do, the engine light keeps coming back on.

Based on that, sounds like a hardware issue. I'll change the other o2 sensor to see what happens with the check engine light.

Still, I have several custom maps, and change them frequently using anywhere from 87 octane to 100 octane. Wondering how many guys have completely changed their ECU module, keeping the original for custom mapping while using a new one is for passing smog. Is it difficult to do?
 
I am also near Sac.
I just removed my S2 downpipe/intake and removed my Hondata tune and passed smog with no issue.

What CEL codes are you seeing? Are they related to o2 sensors?
 
You should be able to pass with the tune unless there was emission equipment disabled (many tuners disable the secondary o2). If you reenable, the readiness monitors should set after a while.
Otherwise, you can't just switch back to stock tune unless your remove the parts. As you have seen, the downpipe is going to throw a CEL for catalyst efficiency.

Sent from my SM-G920V using Tapatalk
 
Yep, exactly what's happening. So can I pass smog immediately after enabling the secondary o2, hoping to get the certificate before throwing a code?
 
You said rediness failed to turn green.

After you returned to stock how many miles did you put on the car before going to smog?

You need to put at least 50 miles on anytime the battery has been disconnect or a reflash of ecu.
 
Hey guys... @freggie (and goofy gf) @dptro (where'd you get the hood?) and @fergy016 (nice color, dude) thanks for weighing in on this. Sorry for the late response... didn't know you guys had followed up. Appreciate that.

Here's what I know:

-- Part of the initial problem is that i needed a new battery... the old one was so weak (unknown to me) that monitors weren't fully resetting. They'd reset partially then need to start all over when battery voltage dropped too low. That's been fixed.

-- Yes, i've been reviewing the monitors' status on FP. (love that thing!) Was driving to Vegas when finally all 7 of my emission monitors were green... then bam! At that very moment I threw a code, the engine light went on. And yes, something about an O2 sensor. &*%$*. Because I had replaced the front sensor just last year (my tuner guy said it wasn't working well) this time I replaced the downstream sensor near the lower part of the DP. So far so good... Only have maybe 75 miles on the new sensor but no new code. Fingers crossed.

-- However, not all 7 of my sensors are green yet. 4 are green, 3 are said to be "unsupported". That's not the way it was before.
I don't know... maybe now they will never turn green. Is that possible? Fortunately nothing is red... only green or yellow i think.

Question -- is it necessary to have all 7 Flash Pro emission monitors green?

Not sure if this is news... the car still runs on a stock map, despite the CAI, DP and exhaust mods. Of course the car runs like absolute crap, rev hangs like crazy... but get it on the freeway and it's not the worst thing in the world.

Anyway, i've taken it in for smog several times and always had issues, like i'm trying to scam the guy doing the test. So i need to make sure next time i get it right.

So what do you guys know about each individual sensor... or about the number of sensors? (BTW... i've kept the CAI in place -- it's CARB approved, as well as the exhaust and DP, which is not... but the guy didn't seem to care about it)

Thanks guys!

P.S. fergy... ever heard of Mosquito Ridge Rd? Great place for a spirited ride; even the run up to Foresthill is nice... just watch for LEO. When guys from 9th Civic stop by that's always the place to do for a little fun. Once on Mosquito, no LEO at all. Just be careful for the occasional pick-up truck. If you need a partner, i'm always down for it: 916-606-1250
 
I believe all readiness monitors must be set before you can pass.

With an aftermarket dp you will likely continue to throw a code once they set. There probably wasn't anything wrong with the rear o2 but the higher flowing downpipe puts the readings out off factory range.

Can your tuner enable the emissions equipment on your tuned calibration?

Sent from my SM-G920V using Tapatalk
 
lol.... yep, threw that code again this morning! (no worries, i suspected as much and kept the other one)

Yes, the tuner did provide a second map just last week with the O2 enabled... not sure what else is enabled, if anything. Normally they are not. Also said something about switching to AFM mode from MAP.

At the beginning of this whole thing he mentioned the stock map wouldn't hurt anything, so thought i'd give it a try. That hasn't worked. Like you said, the DP is putting the readings out of factory range. Would a smog technician be able to determine the bad readings even if I turned off the "MIL", check engine light?

Or would it be better to use the custom map since i'm leaving the DP on? (And it's the DP that's causing the problems, right... not the CAI or exhaust?)
 
I would pick one of 2 options

1. Leave aftermarket parts. Use your custom tuned map with emissions enabled
2. Return intake and exhaust to stock and flash back to stock map.

Running a CAI on the stock map can also cause a CEL


Sent from my SM-G920V using Tapatalk
 
Returning to stock isn't really an option. (btw -- it's a Full Race with cat) So i'll try the custom map.
Thanks a lot guys... really appreciate it. Will keep ya posted!
 
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