jwlmike

I have a 98 jdm itr motor in my 98 civic. I pass the visual and functional tests, but failed the emissions test. My HC's are too high at idle. Co and nox are all within specs.
passing 100ppm
First visit: hc 412ppm
Second visit: 165ppm
I have a comptech intake, jdm 4-1 header, carsound cat, and greddy evo exhaust and usdm p73 ecu. I replace the cap, rotor, spark plugs, and the oil. Changeing all this brought it down 250ppm, but I still need to bring 100 or less.
Does anyone else know what I can do to bring it down even more?
Any help would be appreciated.

Chris y0!

how did you pass visual with a JDM header?

are you running on regular 87 octane?

did you try putting your stock cat on?

all stock

make sure the cat is really really warm when they do the testing. keep ur car running when u park infront of the ref's. if u want the BAR that bad, how long have you had the carsound for? might want to buy a new one just for the test.

B_CRUZ!

use a LS or gs-r header. the cast ones don't get cool as fast and it retains the heat.

nema741

I'm glad i live in CT.

93SSPHatch

I had the same problem as you did. The ref told me that the high HC's were caused by some sort of misfire- either a rich or lean misfire. So on my FIFTH test, I kept the cat super hot, and retarded my timing all the way back to 14BTDC. For me, passing the emissions test was the hardest part.

Good luck, it is well worth it once the ref pastes that sticker on your car.

turbolscivic94

you could try dousing the internals of your muffler in a mixture of water and rubbing alcohol, or just get a v-afc and lean that bitch out a bunch for the echeck.

Dr. EKology

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b.cruz &raquo;</TD></TR><TR><TD CLASS="quote">use a LS or gs-r header. the cast ones don't get cool as fast and it retains the heat.</TD></TR></TABLE>

Cast header Timing retardation

93SSPHatch

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbolscivic94 &raquo;</TD></TR><TR><TD CLASS="quote">you could try dousing the internals of your muffler in a mixture of water and rubbing alcohol, or just get a v-afc and lean that bitch out a bunch for the echeck.</TD></TR></TABLE>

Leaning out is not the answer; if you go to lean, then your NOX goes through the roof.

ATS*VEEE

clean out your throttle body and as much of the intake manifold with carb cleaner as possible (reach way in there). And yes drive like 30 miles before going, gets the cat nice and warm.

jwlmike

I did clean the tb and inside the im as much as I can. Before I go to the ref again, im going to swap out the header and cat and retard the timing a little. I think my cat might be dead. I had it for about 2 month now. Will 87 octane gas help lower it HC's. Does anyone or have anyone tried the iso-heet bottle that you poor in your gas tank?

acuracing

I would suggest replacing the header and cat as others have stated. I drove around for a bit before I took the test, but the car was off for a good part before I took the test. Regardless, I still passed with flying colors.

The easiest way to prep for the ref and smog is to return your car as close to stock if possible. A little work beforehand goes a long way.

Dr. EKology

I highly doubt 87 octane would help, I actually think it would make you do worse. Higher octanes will usually burn hotter since they burn thuroughly, evenly, and completely. And instead of a high-flow cat, maybe you should look into a more restrictive, better cleaning cat?

93SSPHatch

[QUOTE=EKology]I highly doubt 87 octane would help, I actually think it would make you do worse. Higher octanes will usually burn hotter since they burn thuroughly, evenly, and completely. And instead of a high-flow cat, maybe you should look into a more restrictive, better cleaning cat?[/ QUOTE]

That is exactly what I had to do. I had to get rid of the Carsound High Flow, in favor of a cat that the muffler shop uses for cars that don't run an EGR system; in other words, I downgraded to an extremely more restrictive cat. You gotta do what you gotta do.

RoaringTurtle

I had a problem with high hc's on idle
everything else passed
found out it was the air filter
so make sure you check that as well

also 2 bottles of iso heet in your gas tank
warm up the cat
you should pass after that

4DRPIMPIN

Try a octane booster and then run 93 octane for 1 full tank then go see the ref....oh yeah replace the fuel filter...and change the oil again..good luck

Dr. EKology

And just a precaution I would ditch your intake and run my stock air box. That should help also.

degooser

how old is your o2 sensor...

get a new one with an OEM clip...when you get that cat...

that should help a lot too.....

o2 first then cat... if you decide to change the o2..

jwlmike

I just picked up a header and a cat. I have a question about the cat. The cat is an oem 98 civic cat. Should I use this oem cat or buy an aftermarket cat from the muffler shop? I heard that the oem is better, but how can I tell if it's still good? How would a NEW aftermarket cat perform vs a USED oem cat?

Dr. EKology

You're running a larger motor with a cat that was made for the tiny d16. I don't think that would be enough. Check with your muffler shop to see what their best cat is. I'm affraid that the stock Civic cat will let a lot of stuff go through.

SkyeC

Get a stock ITR/ls/gsr/whatever header and cat.

Those carsounds combined with an aftermarket header have a hard time getting hot enough for stringent CA emissions.

Marauder

The OEM cat will clean the exhaust better than any aftermarket cat. Stick with that and swap it out after you pass emissions test.

jwlmike

Does mis adjusted valves have an effect on the emissions?

Marauder

Yes, if they are open when they are not supposed to be.

Lord Helmet

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kazejin &raquo;</TD></TR><TR><TD CLASS="quote">Does mis adjusted valves have an effect on the emissions?</TD></TR></TABLE>

yes valves that are not properly adjusted will effect the smog test.