Ritchie

hey, i brought my car today for smog check, but i failed. it is a 1992 honda civic vx with a d16z6 swap. the smog technician said it might be due to a bad cat converter, but anyone got any suggestions? here is the test result...

tech8

The high NO (Nitric Oxide) probably is because of a bad cat. Your car failed the worse there.

Ritchie

would an aftermarket cat converter fix the problem? i have a RSR exhaust and not the stock one.

951BRO

did he run it cold? i say romp the **** out of the car before you run it again , run injector cleaner, and cram steel wool or try it again


or you can just smog it like my homies sr20det smogged

Ritchie

the smog guy ran it twice. i guess the first time he was trying to warm it up. injector cleaner is the one that chevron makes, right? if so, i did put some of those in. any more suggestions?

tech8

An aftermarket cat will probably fix, if not at the very least help, with the failed emissions. The cat helps remove many of the pollutant before it leaves the car.

The NO emission is too high for many of the little tricks out there to help.

Ritchie

any suggestion a brand of cat converter? or are they all the same?

tech8

Magna Flow by Car Sound is good, and has a direct-fit for your car. Cats are not all the same, the better ones (e.g., stock) will last longer, as it has more of the more of the catalyst materials.

http://www.car-sound.com/02pro...22635

Ritchie

yeah, but the car never came with a stock exhaust or cat converter so i bought a RSR exhaust with probably an old cat.

tech8

They make universal fit cats too. You can always call some muffler shops for their cat prices, sometimes you could get one for around $100.

Ritchie

alright cool. in most cases, would the result of Gross Polluter because of a bad cat or is there more to this problem?

tech8

Your HC and CO emissions are not too far off, it is mainly your NO emission.

It can be something else contributing to the emissions (for example, needs a tune-up); but, replacing the cat usually helps alot with the high NO emission.

Something wrong with the EGR system can also cause high NO emission; but other than the cat, most other things you do to the car won't lower the NO emission by much.

thesmogman

Yes Bad Cat.

When all of your numbers are up the CAT is normally the problem. Your O2 readings are up too. Normal 02 readings would be 0.0 or 0.1 anything over that without an EGR or AIR system points to the cat(Unless it was not warmed up enough for the test.) That is unless you have an exhaust leak.

When I suggest that it is time for a cat I tell everyone get the O2 sensor too. The O2 sensors responsibility is to vary rich to lean so the cat stays happy and works efficient.

If you put on a new cat it might pass, But with a bad O2 sensor the cat will not last very long and it will burn up and you will be in the same boat in two years.

A high flow cat is not the answer. These are designed for flow and get you barely to passing numbers. Also the tech's don't like to pre-condition them correctly to get them to pass.

Ritchie

Hmm, the O2 sensor is new, but I don't know how old the cat is. Replacing the cat is worth a shot since I don't really have any clue. As far as tune-up goes, I pretty much replaced everything new other than the distributor cap and rotor.

thesmogman

My numbers for Nox were 3xxx and when I replaced the cat there was nothing in it. It had blown out the ceramics/honeycomb completely.

Cap and rotor if bad would only raise HC and CO not Nox numbers.

If you don't know the condition of them, check to see if the rotor is on tight. Two things, 1) check rotor screw is tight. 2) See if the rotor wiggles or is loose. My rotor seperated from the metal sleeve inside it.

Ritchie

I'll give that a try. Will I be better off finding an used OEM cat or changing an aftermarket one?

thesmogman

I just got a stock replacement cat. It has worked for me for two years now. $86 bucks.

Don't waste your time with a used cat! It can be contaminated from coolant and such.

Ritchie

Alright, I will go to my local muffler shop on Monday.

Hybrid96EK

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tech8 &raquo;</TD></TR><TR><TD CLASS="quote">The high NO (Nitric Oxide) probably is because of a bad cat. Your car failed the worse there.</TD></TR></TABLE>

Thats not even close to what NO stands for in those reports. Its Nitrogen Oxide. Dunno what "nitric" oxide is man. NO is a result of high cylinder temps. He could have a bad cat or a lean misfire.

Ritchie

Hmm lean misfire? Think you can explain what that mean?

Digithalgravel

high NO levels can also be caused by your ignition timing not being in spec, but on the paper it shows 16btdc so..

Hybrid96EK

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HondaEGG &raquo;</TD></TR><TR><TD CLASS="quote">Hmm lean misfire? Think you can explain what that mean?</TD></TR></TABLE>

Just as it sounds... here..

http://www.aa1car.com/library/misfire.htm

EM1SiR85

i would bribe him and make him run another car with your info.

Ritchie

I would too, but rather just troubleshoot the problem and fix it.

Ritchie

After replacing a cat, should I go straight to the smog center or should I drive it around first?