ltltgr

I just did smog test for the second time and did not pass. Need help, any suggestion. I am in the Los Angeles area.

Tom93R1

iTrader: (2)

I failed pretty bad and later found out the high flow cat installed by the previous owner did not have an air pump connection. Meineke welded one on and I passed with flying colors. Probably not your problem but only takes a second to look for.

ltltgr

I have a high flow, and cat back exhaust, I put all the I.C. and airbox back in the car for the second test. I do have my air pump working and connected.

spurvo

How old is that O2 sensor?

ltltgr

i dont think i ever change the O2 sensor, could that be the cause?

ltltgr

can O2 sensor affect smog test?

RX7 8U

iTrader: (1)

Register the car at a non-biannual smog address and you're done.

ltltgr

hmmmm . . never heard of that. . . where would that be

Nathan Kwok

I would get to the bottom of the problem, because with your mods you should have no problem passing unless there is something wrong with the cat. Make sure the airpump is engaging. Also, where are you failing, idle, 15mph, or 25mph, and what part are you failing? This will help us diagnose.

ltltgr

I am failing at HC.

15mph max 88 me 107
25 mph max 53 me 125

Jedon

I just had the same problem and passed yesterday easily. Here is what I did:
1. change the spark plugs
2. change the oil
3. run the tank down to about 5 gallons and put in two gallons of denatured alcohol.
-Jedon

ltltgr

I just change the oil, I think i will do the spark plug today or tomorrow. but where do you get denatured alcohol. Should I be changing the 02 sensor

thanx

Jedon

If your 02 sensor is bad, you will fail smog. Mine was working so I passed. I have heard if you run enough alcohol that you could pass without cats even.

Jedon

Here is my post in the other thread:
passed finally!!
1. A few weeks after my first test my air pump seized and took out my belt, so I bought a used one.
2. changed the spark plugs
3. changed the oil
4. 2 gallons of denatured alcohol into 5 gallons of gas
I think 4 was the clencher.
New numbers:
HC (PPM):
Measured 25 @ 15mph, Allowed 88
Measured 16 @ 15mph, Allowed 53
So I went from 146 to 25 and from 83 to 16 !!!!!
wow, alchohol is cool! too bad it is so bad for the fuel lines and costs $9/gallon.

spurvo

O2 sensors officially last 50 - 60K miles. In reality, they start giving the ECU erroneous air/fuel mixture values (really, just the air left over after combustion) by 20K or so. As it begins to fail, the ECU responds by enriching the fuel mixture, leading to more HC's than the cats can clean up. Not saying this IS your problem, just a possible candidate. I replaced mine at 60K, and the difference in driveability was impressive. I passed smog with the old one, but unclean fuels can really screw them up. I'd replace it anyway, you can find them pretty cheap at http://oxygensensors.com/