My '89 Civic (4 dr, LX, 5 speed) failed CA smog again. A bit of background on this issue: I bought the car about 5 weeks ago and took it to get an enhanced smog check. It failed NOx at both 15 mph and 25 mph readings taken on the dyno. Other emissions were normal.

I had the registration changed to the Bay Area from Sacramento and was able to get a normal smog check after calling BAR to get the status changed. The car failed the normal smog check (taken at idle) because the HC levels were around 300 (passing is below 100). Several technicians I spoke to as well as my research on both the internet and in automotive books pointed to only one thing...a bad catalytic converter.

After the second failure I had the Cat replaced (two days ago) with a brand new one and took it for the third smog check yesterday. I was pretty shocked when the HC's still showed around 270-280. I don't know what else I can do. The idle is right around 750, ignition timing seems fine, i'm running 87 octane, almost all the ignition components are brand new (wires, plugs, cap, rotor, etc). The car is not running hot and the oil was changed 10 days ago. I made sure to get the cat nice and hot before the check with some WOT runs. I also left it running while waiting. Mileage is 156,200 and the car runs great. I don't know what else to do.

Any help would be much appreciated.


[Modified by oi-punx, 7:33 PM 12/11/2002]


[Modified by oi-punx, 7:35 PM 12/11/2002]

 

Here are some things that might help, although I'm not really familiar with smog certification:

new 02 sensor/s.
new spark plugs
fuel injector cleaner
reset ecu after you make any changes

 

..and make sure your engine is grounded well. lol I'm always talking about that.

 

Have your valves adjusted and run premium fuel. Tough to troubleshoot a specific cause of a failure like that without the car in front of me.

 

if you just got a new cat, you probably aren't light it off. drive around on a highway going 55 in third (keep your revs at about 4k-5k) for about 30 minutes to really heat up the cat and get it to it's operational temperature. then, while waiting in line at the testing station, keep the revs at about 3k-3.5k to make sure the cat doesn't cool off.

a cat only starts doing it's job once it reaches a certian temperature, and believe me, driving stop and go for 5 miles to the station isn't gonna cut it. if that temp isn't reached, you might as well not have a cat on your car.

with the work you've aleady done, i'm pretty sure if you do this, you'll pass no problem.

 

I was told by the CARB people that the SELLER is responsible for a car that must pass smog when sold. Which means, I think that you can go after the people that sold it to you and have them fix it. Make sure all the spark plugs are firing. That is what made our saturn miss smog, but it became the dragster instead.

 

Thanks everyone for the tips. I am working with the seller on getting this fixed. He paid for the new cat. I just replaced the plugs 3 weeks ago. The engine is running very smooth and has plenty of power so i'm fairly certain it is running on all 4 cylinders. Once the car is warmed up I hear very little lifter noise. I wouldn't think that out of adjustment valves would cause HC levels to climb that high but i'm not ruling that out as the cause.

The problem may be that I didn't heat up the cat enough. I went from full cold to the smog station in about 20 minutes in stop and go (about 8 miles) with 10 minutes of idling @ 750rpm at the station so it may have indeed cooled off too much. My WOT runs were also in thick traffic and only up to about 55. Since this is the most convenient and cheapest test I will try it first.

Any other tips or advice, again is much appreciated.


[Modified by oi-punx, 9:43 PM 12/11/2002]

 

02 sensor is another culprit, and advancing the timing as far as spec allows will bring HC down but NOX up.

 

It might be worth it to just replace the O2 sensor given the mileage. Are they easy to replace on these cars? I'm assuming that they probably are compared to what i'm used to working on. Does anyone have short write up on the replacement or a link to one? Are the sensors available at any auto parts store or are they a
dealer only item?

Thanks

 

bam, you have it right there. dude, it's not that your cat cooled off, the problem is it never even got enough to start working. i can basically guarantee that if you drive around at 4-5k rpms for 30 minutes before the test (a full 30 minutes) and idle at 3.5k in line, you'll pass with flying colors. if you do that, and still don't pass, i'll paypal you a buck.

 

Ha! I'll take you up on that offer. I will follow your directions precisely and will post on the forum how it turns out. I mean it's a brand new cat, HC numbers should be much lower than what I posted above assuming that the cat is working properly.

As for the O2 sensor, i know one way to tell that they are shot is that car has a rough idle. My idle stays pretty consisent with that posted under the hood (750 +/- 50). It's definitely not jumping around all over the place.

I'm keeping my fingers crossed that you are right about the low temp for the cat.

 

get the bottle of guaranteed to pass emissions. works like a charm.

 

Hc are from running rich. Try leaning it out a little. dont go to much or else you will raise nox

 

HC is raw fuel, high HC is caused by a misfire. CO is a by-product of incomplete combustion, the result of a mixture that is too rich. A misfire can be caused by several things, valves that are too tight, a problem in the secondary ignition system (spark plugs,plug wires,distributor cap, ignition rotor), a lean misfire from a mixture that is too lean, a rich misfire-mixture is too rich, a problem with the egr staying open at idle can cause a misfire, and mechanical problems such as burnt valves or excessively worn piston rings.
The four or five gas analyzer will tell you alot about what is going on in your engine. If your engine is running efficiently, your CO2 (not CO) should be at 13% or higher. Oxygen content of the exhaust will tell you alot too. If there is not enough oxygen in the exhaust, catalytic converter efficiency will be greatly reduced. Don't keep guessing about what is wrong with your car, it will cost you a fortune to keep throwing parts at it with no clear idea of what the problem is. Use a methodical approach to troubleshooting, get professional help if you are in over your head. Good luck.

 

I got my JRSC'd ITR to pass by lowering the fuel pressure, it made a big enough difference to sneak past the legal emission standard. There is no way really to lower fuel pressure on a stock engine, however unless you purchase an adjustable regulator. Your car should pass without having to do that though. Try slipping the inspector a 50 and see how good it does when the emission probe falls out of the tailpipe... LOL

 

Try retarding your timing to like 10 degrees and setting your idle to like 1100 and go try it like that..Drive the car for about 30 minutes before testing also.. It will pass..

 

That's what I'd do too.
Oxides of Nitrogen are increased when you advance your timing. So try retarding it.

 

Just an update for those that offered their advice. I took the car out this morning in the rain and ran it HARD on the freeway. I drove around for about 30 minutes in 3rd around 65 mph for 90% of the time. The tach was between 4.5 and 5k RPM. I went to the smog station and immediately had the technician hook up the induction cable and sniffer. Unfortunately the HC level was hovering around 180-200ppm (passing is less than 120ppm).

He revved it for me for around 30 seconds and left it idling. The HC level lowered itself to around 20 and stayed there. He then asked me if I wanted to do the test saying that he felt it may pass. I agreed and nervously awaited the results. Unbeknownst to me California now requires (normal) smog checks to be done at 2500 RPM and at idle.

He first tested it at 2500 RPM and then at idle. I was pretty shocked when the readings came back. Here they are:

C02 Idle -- 14.6% 2500 RPM -- 15.1%
O2 Idle -- 1.0 % 2500 RPM -- 0.1%
CO Idle -- 0% 2500 RPM -- 0%
HC Idle -- 1 ppm 2500 RPM -- 7 ppm

Needless to say I passed with flying colors. I couldn't believe how damn low the HC levels were. I guess a new cat will do that.

Thanks for everyone's help on this. This board is awesome.

 

YES!!! my dollar is safe!

awesome dude, great to hear.