smog problem
Thread Starter
Intermediate
Joined: Jun 2013
Posts: 42
Likes: 0
From: SO SAN FRAN CA
smog problem
Two years ago failed smog. NO (PPM) 452. Ox sensor. This time NO (PPM) 582. Drive about 1000 mi a year. Checking for cause now. Any ideas. NO codes or check engine light
Last edited by bruceqmed; May 15, 2014 at 05:25 PM.
Pro
Joined: Nov 2002
Posts: 717
Likes: 11
From: Pleasanton CA
Burning Brakes
Joined: Dec 2003
Posts: 1,243
Likes: 5
From: Loveland CO
So did you fail NOx? What were the readings and what was the limit? Do you have any mods done on the car? depending on how close you were you might be able to add a few gallons of E85 and clean up the readings....
Can you put a pic/scan of the inspection report?
Can you put a pic/scan of the inspection report?
Thread Starter
Intermediate
Joined: Jun 2013
Posts: 42
Likes: 0
From: SO SAN FRAN CA
15 mph-1308 rpm-CO2%14.60-02%0.11--HC (PPM) MAX 55- AVE4-MEAS7-CO% MAX0.50-AVE0.01-MEAS0.01- NO(PPM) MAX 437-AVE16- FAILED THIS MEAS 581= 25MPH PASSED. 15 MPH FAILED. XPIPE, BORLA EXHAUST
Last edited by bruceqmed; May 15, 2014 at 05:53 PM.
Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
How long or far do you drive your car before taking it to the SMOG test. Due to the low miles on your car it looks like you dont drive it that much. If you only drive it 5 miles to the smog test, you may not have reached operating temperature yet.
I take several of my cars to get smogged, and will usually go for a 20 mile drive around 280 freeway, or 880 freeway before going to the smog test. Just to get the car up to temp.
kdf
I take several of my cars to get smogged, and will usually go for a 20 mile drive around 280 freeway, or 880 freeway before going to the smog test. Just to get the car up to temp.
kdf
Team Owner
Joined: Mar 2001
Posts: 21,325
Likes: 3,841
From: small town in S.E Pa. PA
St. Jude Donor '03-'04
How long or far do you drive your car before taking it to the SMOG test. Due to the low miles on your car it looks like you dont drive it that much. If you only drive it 5 miles to the smog test, you may not have reached operating temperature yet.
I take several of my cars to get smogged, and will usually go for a 20 mile drive around 280 freeway, or 880 freeway before going to the smog test. Just to get the car up to temp.
kdf
I take several of my cars to get smogged, and will usually go for a 20 mile drive around 280 freeway, or 880 freeway before going to the smog test. Just to get the car up to temp.
kdf
Bill aka ET
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Melting Slicks
Joined: Aug 2008
Posts: 3,451
Likes: 27
From: Bay Area CA
How long or far do you drive your car before taking it to the SMOG test. Due to the low miles on your car it looks like you dont drive it that much. If you only drive it 5 miles to the smog test, you may not have reached operating temperature yet.
I take several of my cars to get smogged, and will usually go for a 20 mile drive around 280 freeway, or 880 freeway before going to the smog test. Just to get the car up to temp.
kdf
I take several of my cars to get smogged, and will usually go for a 20 mile drive around 280 freeway, or 880 freeway before going to the smog test. Just to get the car up to temp.
kdf
Drive the crap out of the car for 20-30 min before taking it to smog.
Burning Brakes
Joined: Jun 2012
Posts: 803
Likes: 42
From: Destin Florida
So in San Fran they still do a tail pipe sniffer test ? I ask because I did ET in the ATL for 11 years and it was strictly OBDII on 96 up cars/trucks. It wasn't until around 2010 they started having us do a visual on cats because they " discovered that some HI Po cars " were using these new things called O2 simulators" to pass emissions without cats lol. But still never went to a 5 gas test.
Race Director
Joined: Dec 2000
Posts: 19,304
Likes: 85
From: San Diego CA
While the above-mentioned advice is true, I don't think super-high NO is being caused a a cold cat.
Nitrous Oxide or NO is created when an engine's combustion chamber temperature reaches over 2500F. Vehicle manufacturers have designed several systems, which when working properly, lower nitrous oxide emissions. Below are common failures which may cause your car, truck, van, suv, or motorhome to produce high high nitrous oxide.
1. Lean Fuel Mixture - Lean fuel mixtures cause high NOx. A lean fuel mixture exists when less fuel then required is delivered to the combustion chambers or when more air then necessary is added to the fuel. In either case the lack of gasoline needed to cool the combustion chambers down is not present. Combustion temperatures increase causing high nitrous oxide emissions. A lean fuel condition may be due to a vacuum leak/s and/or defective fuel control components, such as the Air Flow Meter, Engine Coolant Temperature Sensor, and O2 sensors.
Read more about the Oxygen Sensor
2. Defective EGR System - The Exhaust Gas Recirculation system is designed to reduce NO. The EGR system consists of an EGR valve, EGR pressure sensor, vacuum hoses, and one or more vacuum switching valves or solenoids. Later model vehicles may be equipped with electronically controlled EGR valves, which do not require vacuum lines or switching solenoids. Electronic EGR systems will have these components built in.
The EGR system's job is to re-route a small amount of exhaust gas back into the intake manifold to help reduce combustion chamber temperatures. As mentioned above NOx is created when combustion chamber temperatures reach above 2500F.
By recirculating exhaust gas back into the intake, a small amount of the air/fuel mixture is replaced with inert gas, reducing combustion temperatures.
Read more about the EGR System
3. Defective Catalytic Converter (CAT) Some vehicle manufactures have designed their cars to operate without EGR valves. Non-EGR equipped vehicles rely heavily on the Catalytic Converter to assist in the reduction of NO. These vehicles have tendencies to develop CAT problems sooner then those which are equipped. If you own a non-EGR equipped vehicle, and have failed the emissions test for high NOx, pay close attention to the Catalytic Converter.
1. Lean Fuel Mixture - Lean fuel mixtures cause high NOx. A lean fuel mixture exists when less fuel then required is delivered to the combustion chambers or when more air then necessary is added to the fuel. In either case the lack of gasoline needed to cool the combustion chambers down is not present. Combustion temperatures increase causing high nitrous oxide emissions. A lean fuel condition may be due to a vacuum leak/s and/or defective fuel control components, such as the Air Flow Meter, Engine Coolant Temperature Sensor, and O2 sensors.
Read more about the Oxygen Sensor
2. Defective EGR System - The Exhaust Gas Recirculation system is designed to reduce NO. The EGR system consists of an EGR valve, EGR pressure sensor, vacuum hoses, and one or more vacuum switching valves or solenoids. Later model vehicles may be equipped with electronically controlled EGR valves, which do not require vacuum lines or switching solenoids. Electronic EGR systems will have these components built in.
The EGR system's job is to re-route a small amount of exhaust gas back into the intake manifold to help reduce combustion chamber temperatures. As mentioned above NOx is created when combustion chamber temperatures reach above 2500F.
By recirculating exhaust gas back into the intake, a small amount of the air/fuel mixture is replaced with inert gas, reducing combustion temperatures.
Read more about the EGR System
3. Defective Catalytic Converter (CAT) Some vehicle manufactures have designed their cars to operate without EGR valves. Non-EGR equipped vehicles rely heavily on the Catalytic Converter to assist in the reduction of NO. These vehicles have tendencies to develop CAT problems sooner then those which are equipped. If you own a non-EGR equipped vehicle, and have failed the emissions test for high NOx, pay close attention to the Catalytic Converter.