86 951 Driver

So I got my car tested it failed twice. Here is the deal.

HC: 2.3 ppm limit 0.8 ppm Fail
CO: 9.0 ppm limit 11.0 ppm Pass
NOx: 2.2 ppm limit I don't remember. I failed this as well.

Here is my question what could be wrong with my car to produce this result? I have replaced the plugs, and I put in about two bottles of ethanol along with that guranteed to pass stuff from autozone. The kid told me its most likely the cat. I put a new one on about 3 or 4 years ago. Could it be bad?
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Litespeeds

It could be your cat or your o2 sensor.

hpservertech

Is this for new registration or renewal? If you can just wait till next month. Starting 9/4 any car older then 95 doesn't have to have emission tests only safety.

otherwise drive it for a good hour or two then take it in for a retest.

boston951

Please tell us more about this.

hpservertech

It's a Missouri thing. It's funny actually. few years ago they changed the emission tests from local auto shops to big state run emission tests....everyone complained. so now they are moving back to letting the auto shops do the emission tests again (since they do the safety inspections). cars older then 95 dont need to have emission tests, cars newer then 95 but driven less then 12,000 miles over 2 years dont either.

Personally I would think that older cars put out more bad emissions then newer cars, but then again I'm not a politician so logical thinking doesn't elude me. Check out www.gatewayvip.com

I failed emissions twice and the only thing it could be is the cat since everything else was replaced. So I'm just going to wait a month to register & plate the car.

86 951 Driver

Here is the deal with waiting til next month, you have to pass before you can be exempt. I just called my mechanic and he told me that I should try changing the o2 sensor, which is a pain in the *** by the way then going back. I will be taking the cat off once I get it past emissions. I will put a resonator/cat look a like.

lilredpo

I failed once, mechanic had equpiment set for wrong number of cylinders.

Another shop once used wrong exhaust setup - I guess there are two different types depending of front or rear wheel drive for dyno.

Try another shop.

Good luck.

944girl

Speaking of O2 sensors...where are they located on our NA's ?

I think I have to replace mine...I don't even know if the original one has ever been replaced or not. I know my car failed CA emissions two years ago and I replaced my cat and it passed. This time it failed the 15 mph test but passed the 25 mph test...so my shop is saying to replace the O2 sensor. FYI...I just replaced the cat again last June 06 so it can't be the cat. Just last year my mechanic refreshed my motor from top to bottom so it can't be that either.

So where are these O2 sensors located again?

Thanks
CH

Weston

The O2 sensor can make a big difference with emissions for these cars, and it's not hard at all to replace. That's where I'd start.

Weston

It's between the cat and where the exhaust attaches to the header... basically, it's right below where the firewall is.

Keithr726

+1 on O2 sensor. My old car didn't pass because of it. It passed easily when the new one was on and there was more power than before.

Mongo

Did you mess with the air flow meter? That can do things with it. The HC's look like you are running rich though...

86 951 Driver

When I get home I'll try to tackle the o2 sensor again. There is not much room to get the wrench in there. I rented the 02 sensor tool, but I couldn't get it up in there and able to turn it. I am going to use a cheater bar and hopefully pass emissions today. Thanks guys for the support. Also would this maybe cause the dip I have at idle. If i rev my car up then let off it will dip a little bit at idle.

DMB14

I failed right after I got my 944. I also failed inspection because my horn did not work. It was a $600 bill to get everything right.

You might be able to get by without doing anything to the car. The car needs to be thoroughly warmed up. I was told to do about 40 minutes of driving before getting the car tested. Also while you're waiting in line to get tested occasionally start the engine and get the revs up to 2000 to keep it warm.

Mongo

Neon, what catalytic converter do you have? I am using a Magnaflow 50-state OBD high flow. It actually does its job when combined with a new O2 sensor.