Here is my problem. I live in Jersey but will only be here for another 5-6 months. I am moving to Florida where they don't even test emissions from what i am told. I am trying to pass emissions here at the least $ cost to me since it won't matter in a few months.

I just failed inspection for NOx. The standard was about 1000 and i got 1831. Everything else passed. CO standard was 132... i got 98.

What i did before inspection:
I had used de-carbonizer but never changed the spark plugs.
Cleaned K&N filter with recharge kit.

From info i have gathered so far i should:
Change spark plugs (which may be very dirty now after de-carbonizing)
Replace EGR Valve
Replave CAT
I might have a slight vacuum leak...how much of a factor does that play into here?

Now...with the NOx being high does that mean that the car is not running at its best and getting low gas mileage etc. So should i fix it all anyway for the sake of having the car running right? Or does it not matter? I planned to get rid of the air restriction of the cat when i moved by replacing it with straight pipe so i would like to get around buying one if i could. THANKS!!

 

clean the port that feeds the egr if you have not already when you replaced the valve. edit: my mistake I see you plan to replace the egr but have not already. you will find they are kinda pricey but if you have the money replacing it would be best... otherwise check it for proper operation and clean the valve in it.

make sure you have the right plugs and not a hotter heat range plug by accident. there should be a sticker on the bottom side of your hood that tells you the exact ngk plug that is for a stock application (among other specs). fresh plugs would be good though... just the standard copper ngks.

find your vaccum leak and fix it, it is not helping you... alot of sensors use vaccum to reference the load the motor has on it and whatnot.

also run through all the gas with this decarbonizer in it... that stuff usually makes the cyl temperatures hotter (too much cyl temp. is what creates the nox).

use regular gas too, dont make the common mistake of thinking premium will help you... it does not.

edited... I read too fast sometimes.

 

I have a friend here who has some experience with emissions. NOx is a product combustion temp. over 2000 degrees usually caused by a lean condition which coincides with your vaccum leak.

He also says to check your timing. Plugs wont be a contributing factor in a NOx failure.

 

My application is not stock. I have bolt-ons:
AEM CAI
DC Header
Cat-back Exhaust
AEM underdrive Pulleys
Fuel Pressure Regulator
I also have adjustable cam gear. How much would it help to retard the timing a few degrees?

How big of a part does fuel pressure play and should it be at stock level, slightly higher, or slightly lower to prevent poor combustion?

Should i get colder plugs to help out?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by snowshooz &raquo;</TD></TR><TR><TD CLASS="quote">I have a friend here who has some experience with emissions. NOx is a product combustion temp. over 2000 degrees usually caused by a lean condition which coincides with your vaccum leak.

He also says to check your timing. Plugs wont be a contributing factor in a NOx failure.</TD></TR></TABLE>

wanna bet me? if you have a hotter heat range plug than factory spec, it will increase the cyl. temperatures during combustion.

your friend should also know that the egr is the main component used to qwench the cyl.s with the recirculated exhaust gases (basically inert gas)... thus droping combustion temperatures. although he is right about it being a lean condition most likely and it is (nox) a result of high combustion temperatures (there is some other possibilities though besides just that, but they are not as common).

a lean condition can be cause by a multitude of different things.

fyi I worked for a couple years at the emissions facility here myself, as such I was certified multiple times in emssions related equiptment and testing.

oh and to add I just passed emissions no cat./ blocked egr and a turbocharged f22... go figure. the post about it is in the FI forum.


Modified by twkdCD595 at 1:01 PM 1/26/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by idewson &raquo;</TD></TR><TR><TD CLASS="quote">My application is not stock. I have bolt-ons:
AEM CAI
DC Header
Cat-back Exhaust
AEM underdrive Pulleys
Fuel Pressure Regulator
I also have adjustable cam gear. How much would it help to retard the timing a few degrees?

How big of a part does fuel pressure play and should it be at stock level, slightly higher, or slightly lower to prevent poor combustion?

Should i get colder plugs to help out?</TD></TR></TABLE>

no use the stock heat range in your application, you do not have any mods that would require a change in heat range.

retarding the timing would not help you, it would make your emissions worse... specifically the Hc (hyrdocarbons, aka unburned fuel) would certainly be increased.

fuel pressure could definately effect emissions. for example... too little pressure would lead to a lean condition, which would run hot and cause nox (Hc would be ok though). too much would result in a rich condition and you would have an issue with too much Hc (although nox would proabably drop cause rich runs cooler, to a point... extremely rich can run hot as well).

what is your fuel pressure set at?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by twkdCD595 &raquo;</TD></TR><TR><TD CLASS="quote">

 

hotter plugs lean out a motor... per a wideband o2 (when tuning my car I have seen the results of a plug change first hand.)

I did not say the plugs were solely responsible, but rather could be adding to a cumlative problem (like the vaccum leak, egr with insufficient flow, fuel pressure being changed without knowing the a/f, the added modifications mostly increasing airflow, etc.)

 

I will have to check on the fuel pressure for an exact measurement but in the mean time what should it be set at? 38-40psi?

 

Don't go buy an EGR valve unless you know for a fact that yours is bad. Most are simply clogged with carbon and will work fine if cleaned out. Spend $30 instead on a vacuum pump/guage. Pull a vacuum on the EGR with the motor running and it should stumble a little. Some cars will almost die but Hondas usually catch themselves and adjust to the air leak quickly. If you don't notice a stumble, your ports are plugged(most probable) or your EGR diaphram is torn or the pintle is stuck(not likely). Make sure you get an EGR gasket first and remove the valve. You will probably see chunks of carbon plugging the ports. Clean the EGR with choke cleaner or a methylene chloride based brake cleaner like Gumout. Do not spray any into the vacuum port. You may need to use a small screw driver to break up some deposits. Pull a vacuum on the valve and see if it actuates. If it does and it holds vacuum the valve is good. Take a piece of steel wool and push against the pintle while twisting the wool in circles to polish the pintle and seat. Do this while pulling a vacuum on the valve and it will shine like new and seal properly. Break loose what carbon you can in the intake ports and suck it out with a shopvac. You didn't say what year and trim your car was and that makes a difference in how you will proceed to clean out the ports in the intake. You will be wasting your money if you buy a new valve and bolt it onto clogged ports especially since your valve is probably good anyway. Vacuum leaks do not cause lean running conditions on Hondas. Their fuel is MAP based, not MAF based. I would do a tune up (plugs, wires, rotor, and cap) ,change the PCV valve, and fix the EGR system. Then I would drive it through a tank of gas with lots of highway miles and go for another inspection. I think a cat would be a waste of time and money since you passed CO and Hydro's.

 

I have a 91 accord Lx. Do you think that the clogged ports on the EGR make it seem like seem like a vacuum leak or is causing it? Is the clogged up ports caused by the previous de-carbonization of the engine, just regular everyday driving conditions or both?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by idewson &raquo;</TD></TR><TR><TD CLASS="quote">I have a 91 accord Lx. Do you think that the clogged ports on the EGR make it seem like seem like a vacuum leak or is causing it? Is the clogged up ports caused by the previous de-carbonization of the engine, just regular everyday driving conditions or both?</TD></TR></TABLE>It's a 15 year old car. The ports are clogged from lots and lots of miles. If you Seafoamed your engine, make it the last time. It didn't clog the ports, but it can cause other problems and is just not necessary. Why do you think you have a vacuum leak?

 

i posted before about the car idling funny. the rpms are not consistent meaning when sitting still the rpms go anywhere from 750 to 950. Up and down...up and down. this happens when i get a slightly stronger vibration every couple of seconds or so. Someone said it might be a vacuum leak. I don't know for sure (don't have the stuff to test it)

I never seafoamed. Are you saying i shouldn't?
I should just remove the EGR and clean it right?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by idewson &raquo;</TD></TR><TR><TD CLASS="quote">i posted before about the car idling funny. the rpms are not consistent meaning when sitting still the rpms go anywhere from 750 to 950. Up and down...up and down. this happens when i get a slightly stronger vibration every couple of seconds or so. Someone said it might be a vacuum leak. I don't know for sure (don't have the stuff to test it)

I never seafoamed. Are you saying i shouldn't?
I should just remove the EGR and clean it right?</TD></TR></TABLE> You said you decarbonized and I assumed you poured something into the motor to do that. I was meaning seafoam in a generic way. I would never pour anything into the engine under the pretense of cleaning or decarbonizing it. You should remove the EGR and clean it and the ports. Do a quick search on EGR port cleaning. There have been ample write-ups in the past month that covers that subject well. Do that before you start your vacuum leak search. On a car as old as yours, you may want to consider buying all of the little o-rings and seals that are on the TB and plenum such as the ones sealing the IACV, FITV, and Boost valve. They are all less than $2 apiece. The dealer may have to order them but they are flat and brittle from age and an easy source of slight vacuum leaks. You should do as I suggested earlier and buy a vacuum guage/pump and then you would have the means to find those leaks. It may also be that your EGR is clogged but not totally plugged and that the pintle is not fully seating when the EGR is off. This would cause a small vacuum leak.

 

MANY THANKS!!

 

Cleaned EGR system over the weekend it had some carbon build up but it didn't seem that bad. I was wondering this though...if my radiator was not working properly and the car starts to overheat when sitting still, would that cause NOx gases too considering the engine is hotter than it should be?

I had a leak and was losing coolant. I fixed it with some leak fixer stuff and it seemed to work. The car stays cool when sitting still now. Do you think that will help??