so today i went to get my car smogged and everything came out fine other then my 15mph NO. the allowed value is 711 max and my car measured out 829.

I kno the difference isnt too much and i am not willin to go buy a new cat converter so please help me bring down my nox level.

Ps. i have changed my oil 2 days ago with spark plugs. cap and rotor are in good condition.

car is a 94 ls stock with NO mods and 155k on the clock.
All help/input is appricated ..

 

check for vacuum leaks

 

i dont have any vacum leaks... the tech said that my combustion is too hot..im guessing maybe sefoam the motor? would that make a difference im only like 120 above max on my NO

 

A single bottle of this took my old 88 Civic from "gross polluter" to "pass". I was failing both HC and NOx, and this cut each by at least 30%.

 

I referred a friend of mine to use that guaranteed to pass because he was only over by like 20 points. He still failed and it ended up being a faulty EGR. They never gave him back his money either.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TunerN00b &raquo;</TD></TR><TR><TD CLASS="quote">

A single bottle of this took my old 88 Civic from "gross polluter" to "pass". I was failing both HC and NOx, and this cut each by at least 30%.</TD></TR></TABLE>

What a shame. If you had solved the actual problem you would have picked up some power and mpg. HC's are partially burned fuel. That's wasted hp and not that hard to fix. You were probably running slightly lean.


OP, for NOx try Seafoam. Carbon build up in the combustion chamber can cause hot spots. Make sure you have the right spark plugs. You're really close maybe just 91 octane will pass you. Also you can retard the base ignition timing slightly but keep it within spec.

 

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

What a shame. If you had solved the actual problem you would have picked up some power and mpg. HC's are partially burned fuel. That's wasted hp and not that hard to fix. You were probably running slightly lean.


OP, for NOx try Seafoam. Carbon build up in the combustion chamber can cause hot spots. Make sure you have the right spark plugs. You're really close maybe just 91 octane will pass you. Also you can retard the base ignition timing slightly but keep it within spec.</TD></TR></TABLE>

Run 87 octane, not 91...

 

A shame? Who gives a ****.. At least the damn car passed smog. Its a freakin 89 civic for christ sake!..

 

i put seafoam thru the vacum line today and lil bit in the gas. i will run out the tank n refill and then go test. also i added some water wetter to my mostly watered down coolant.

 

I would hate to ruin your day, but now you need to change your plugs after you fill your tank.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by baller status &raquo;</TD></TR><TR><TD CLASS="quote">
What a shame. If you had solved the actual problem you would have picked up some power and mpg. HC's are partially burned fuel. That's wasted hp and not that hard to fix. You were probably running slightly lean.
</TD></TR></TABLE>

The problem was my girlfriend (at the time) was too broke to get a better car, and had to accept the 88 Civic I bought off eBay (this was 1999).

And yes, it would have been rather difficult for a college student without a garage or other place to work on the car to fix the issues. The cat was failing, hence high HC and NOx levels. Replacing the cat wouldn't have produced any power or mileage gain, just cleaner exhaust.

Besides, we needed the car to last 2 years. It lasted 3. I think she got my $950 worth of use out of it. (She then bought a Jetta and thankfully I haven't seen her since.)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by baller status &raquo;</TD></TR><TR><TD CLASS="quote">
OP, for NOx try Seafoam. Carbon build up in the combustion chamber can cause hot spots. Make sure you have the right spark plugs. You're really close maybe just 91 octane will pass you. Also you can retard the base ignition timing slightly but keep it within spec.</TD></TR></TABLE>

91 could end up increasing HC levels (especially with retarded timing).

Retarding timing can reduce NOx levels, but how is that any less of a "shame" than running lower combustion temp fuel (alcohol) to pass? The problem still isn't getting fixed...

 

well thanks everybody for their help... car passed after i seafoamed it.. so.. SEAFOAM..ftw.. barely passed though and im sure my cat is bad since it was sitting in my backyard for about 2 years.