The various chemicals emitted in exhaust gasses from an internal combustion engine. The usual gasses which are measured through emissions testing are Nitrogen Oxide (NO2), Carbon Monoxide (CO2), and HydroCarbons (HC).

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What is the point of the exhaust?

I was thinking today, what is the actual point of an exhaust? Why can't we just have a pipe going out the front of a car instead of taking all the gases to the back of the car? I can only see ...
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3answers
138k views

What does a water like drop coming out of the exhaust of the car signify?

Sometimes while driving in the traffic, I come across a car or two which would be dripping water-like drop from it's exhaust steadily in a break of 4-5 seconds. I tried to ask a couple of people at ...
10
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1answer
217 views

How does raw fuel damage the catalytic converter?

I was wondering, if fuel gets in the catalytic converter, how does it damage it?
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2answers
185 views

How are diesel engines better for the environment than gasoline?

I understand that diesel engines have become much more efficient at controlling emissions over the last couple decades. Various websites like this one describe the technological improvements that have ...
8
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3answers
548 views

Why don't all diesel engines have throttle plates?

I learned recently that many older and some newer diesels don't have throttle plates to control airflow. I was also quite shocked to learn about a condition called diesel engine runaway. Apparently ...
8
votes
1answer
64 views

What is the “Activated Carbon Cannister”?

Why do I have an "Activated Carbon Cannister" in my unleaded/petrol car? What is it's purpose? How does it work? Do I need to do anything to maintain it? I would like a general answer, but my car ...
8
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1answer
74 views

Connecting to the Battery During Emissions Testing to Measure RPMs?

When doing emissions testing, they connect to the battery, either directly, or using the cigarette lighter socket. I'm assuming that this is to measure the RPMs, as the only other thing connected ...
8
votes
4answers
17k views

What effect will removing my EGR have?

My 2003 Jetta TDI check engine light recently came on, and a scan by Advance Auto revealed code P0401 -- EGR insufficient flow. I took the vehicle to the local TDI guru, who gave me the option of ...
7
votes
3answers
2k views

Why are VW recalling their cars to remove a defeat device?

As I understand it, Volkswagen had software to artificially enhance their efficiency ratings on a test rig. Since it would only be active under test, what is the point of recalling millions of cars to ...
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2answers
8k views

Should I replace my own oxygen sensor if i have a Check Engine Light and Code P2195?

My 2003 focus lx 2.0L L4 SOHC ~18,000 miles has had the engine light so i went to autozone to read the code. Autozone obd2 printout says "P2195 lack of heated oxygen sensor- Bank 1 Sensor 1 HO2S11 ...
6
votes
4answers
231 views

Cheap vs Expensive Fuels [closed]

What is the difference between the cheapest fuels in a place like Tesco's and the 'high quality', highly priced competitors? Is there actually any noticeable difference in available power, engine ...
5
votes
2answers
151 views

How is barometric pressure related to emissions testing?

In the VW emissions cheating scandal, news reports say the following: According to the EPA, "the position of the steering wheel, vehicle speed, the duration of the engine's operation, and barometric ...
5
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2answers
84 views

Emissions Problem: Lambda AND CO Slightly High on my 98 Mazda 626

I just took my 98 Mazda 626 for it's inspection and they said the carbon monoxide is slightly high. The test is done using a tail pipe gas analyzer while holding the RPMs between 2500 - 2800 for ...
5
votes
1answer
228 views

How to know whether a Lexus rx450h qualifies for California Emissions standards?

I'm looking at a 2012 Lexus rx450h but will be moving to one of the states (Arizona, Connecticut, Maine, Maryland, Massachusetts, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, ...
5
votes
1answer
2k views

How to determine if P0430 is O2 or catalytic converter

2009 CTS4 3.6L P0430 catalyst below efficiency bank 2 comes on periodically. (There are no other codes being thrown.) I put a data logger on it today on my drive to work and the rear sensor is ...
5
votes
1answer
192 views

2003 Toyota Rav4 ECT Too Low for Readiness Monitor Drive Pattern

I recently failed an emissions test because my CAT and EVAP readiness monitors were "Not Ready" following a reset check engine light a few weeks back, which told me that the engine coolant wasn't ...
5
votes
1answer
3k views

Passing Emissions Test: Can't figure out how to fix code P0705 on a 1997 Nissan D21 / Hardbody / Pickup

So hello. I have had a lot of luck with my other vehicles on forums and a recently became the (hopefully-soon-to-be)-proud owner of a 1997 Nissan D21/Hardbody/Pickup XE. It has 156k miles on it and is ...
5
votes
1answer
292 views

Ibiza Mk2 MOT emissions test failure

I've had my SEAT Ibiza Mk2 for about three years and it's just failed its MOT on the emissions test - there's fuel in the exhaust on idle, and only on idle. It's in the garage at the moment and they'...
4
votes
2answers
865 views

How to install a California oxygen sensor into a federal catalytic converter assembly?

I have a 2000 Mitsubishi Galant ES 2.4L Engine with California emissions. Installed is a new federal catalytic converter assembly. The problem is that I do not know what kind of oxygen sensor to ...
4
votes
5answers
4k views

2011 Chevrolet Cruze - Clicking Noise When Braking

So I leased a 2011 Chevrolet Cruze, brand new (only 2 miles on it), last November, 2010. It was running perfectly fine for a while. Brought it in for the standard tire rotation/oil change a few months ...
4
votes
1answer
88 views

Exhaust on a replaced motor

I recently had to change the motor in my 2004 Hyundai Sonata. I bought a used one from the junkyard, and it fired right up after I got it put in, and all the wires, hoses, etc. connected. The only ...
4
votes
1answer
70 views

Car loses power while driving very briefly and on hills?

At this point I am positive it has something to do with the exhaust system but I am hoping to narrow down whether its a bad sensor or a gasket issue. I will replace them all but kind of enjoying the ...
4
votes
1answer
121 views

Evaporator canister purge system advice needed

1995 Blazer - 4.3 L Vortec V6 CMFI (vin W w/ PCM) 230,000 miles There are no trouble codes. This is a OBD-I or 1.5 system from a GM transitional year (I have the OBD-II style connector). I have ...
4
votes
0answers
216 views

Evap. circuit malfunction on Mercedes Benz

I have a 2002 ML320 suv. The CEL is on, and the code is P0446. It states that there is something wrong with the evap. system circuit, specifically at the charcoal canister shut-off valve. I've tried ...
3
votes
3answers
85 views

EFI engine car failed Emission test?

i have an EFI engine car (Nissan N16 Super Saloon - 2000yr) i bought it 6monthes ago as an used car. After i bought it, i had check engine lights on, then i drove it to a mechanical shop few times ...
3
votes
2answers
38 views

What fuel injectors I have to install? [duplicate]

Recently the fuel injectors of my Mazda 3 SP5 2006 2.3L stop working, they still works, but my mechanic said that are in bad conditions. Anyway, when I search the fuel injectors for my car, I found ...
3
votes
3answers
719 views

Failed inspection on because of OBD2 readiness

My 2008 Hyundai failed inspection because the OBD-II system is in a "not ready" state. The mechanic asked if my battery had died recently. It had, after getting an alignment. He suggested driving on ...
3
votes
2answers
7k views

Failed emissions - high lambda, low HC and CO

My 2007 Daihatsu has failed the national car test on emissions. The readings at 3500rpm are: Lambda: 1.10 (normal range 0.97 - 1.03) CO: 0.02% volume (normal range below 0.20%) HC: 11ppm (normal ...
3
votes
1answer
581 views

Is a secondary air injection pump motor necessary?

My check engine light came on and the mechanic said the problem is that the secondary air injection pump motor broke. It's a used car (2004 VW new beetle) with about 150,000 miles on it and the parts ...
3
votes
3answers
2k views

Will a universal catalytic converter set off the check engine light on an Infiniti G35?

I have a 2004 Infiniti G35 and the bank 2 catalytic converter has triggered the check engine light. If I replace it with a universal Magnaflow catalytic converter (approximately $100) will the check ...
3
votes
2answers
320 views

Access to EVAP Canister Vent Valve

My TSX is coding P2422 - EVAP Canister Shut Valve close malfunction. I'm finding posts online that it is often a blockage (spider nest??) that can be blown out with air. I'd like to try that first ...
3
votes
2answers
2k views

2000 Nissan Maxima Service engine light

The dealer diagnosed it and says it got tripped by catalytic converter and rear oxygen sensor. The total estimate was around $2000. The blue book value on his car is around that amount. Is there a way ...
3
votes
1answer
54 views

Possible Fuel pump damage

My Toyota Vitz 2007 idles very rough. Sometimes it stalls if I suddenly stop after few miles drive. I took the vehicle to a mechanic and he cleaned up the fuel pump. He used compressed air to clean ...
3
votes
1answer
757 views

Which O2 sensor is bad?

I'm getting codes p0031 and p1148 on my 2007 Altima 3.5 SE. From what I've read, p1148 is caused by p0031. P0031 relates to the voltage on the heater circuit of the 02 sensor on Bank 1, Sensor 1. I ...
3
votes
1answer
27 views

2005 PT Cruiser Emissions Light On Periodically

The emissions light comes on and while driving, it starts to jerk as if driving a standard transmission and not using the clutch properly. Take my foot of the gas pedal & it will stop for a few ...
3
votes
2answers
58 views

1980 Chrysler LeBaron Failed Emissions Test

My 1980 Chrysler LeBaron (V8 318ci) just failed an emissions test. I'm coming from a state without emissions testing to a state that requires it. Specifically, the only part that failed was the ...
3
votes
1answer
48 views

1993 Ford Taurus LX 3.0 Catalytic Converter

I've failed my smog test 3 times in a row within a week. They told me it was the EGR. So I changed my EGR Valve, EGR Solenoid, and my EGR Pressure sensor. The vacuum lines running from the EGR Valve ...
3
votes
1answer
69 views

2012 Audi Failed Smog - Will Dealer Repair for Free?

I received a surprise today when my 2012 Audi Q5 failed its smog emission test in Nevada. I've never had a car fail and is surprising for a 3 year-old Audi. I was told that it was part of the oxygen ...
3
votes
2answers
1k views

Engine Revving/Misfiring - Formerly Running Lean - No Trouble Codes Now

For a few months now my 1999 Toyota Avalon XLS (California model - this apparently affects the emissions specs - I'm in NY however) with around 105k miles has been giving me these totally random ...
2
votes
1answer
75 views

CO, NOx, HC plot with AFR Table [closed]

Can someone provide me with a lookup table (reliable of course), or a plot (with exact plot to scale) for CO, NOx, HC emission from a SI engine? If possible, I am also looking for the same with for ...
2
votes
2answers
312 views

Formula to calculate emission rates

OBD tells whether I have passed the emission test or not. I want to know the formula by which it calculates the rate of CO, NOx, HC emission from my car and compares it with some set threshold value ...
2
votes
1answer
66 views

Are CO2 emissions proportional to MPG figures?

I was looking at the car tax (VED) system in the UK, as I'm considering buying a new car. I was just wondering, are CO2 emissions always proportional to the MPG figure of a car, both in theory - ...
2
votes
1answer
93 views

Difference between fuel injectors and emissions standards

I have a 2004 Honda Accord EX Sedan with a 2.4L I-4 with California emissions and 250k miles on it. I desperately need to replace my fuel injectors but the price is steep! Can someone explain to me ...
2
votes
1answer
177 views

Replacement Interval for Carbon or Charcoal Canister

How often should the Carbon or Charcoal Canister for most vehicles be replaced?
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vote
3answers
14k views

Best Ways to Pass Emissions?

I recently bought a 1989 Mercedes 300E that didn't run. Has a straight-six gas engine. Thanks to the miracle of Seafoam and a lot of luck, I was able to get fuel delivery happening again. I then ...
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vote
1answer
337 views

How to know if a '97 Ford Escort Engine is Federal Emissions or California Emissions

I did a search on the VIN and the engine type is listed as: 2.0L I4 SPI Can anyone tell if it is California or Federal Emissions? From what I've been told they have completely different intake ...
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1answer
153 views

Drive cycle on 2001 Saab 95 with codes P1312 & P1110

I replaced DIC, did a basic drive cycle to remove codes, but didn't remove codes. All my monitors are in ready state. The check engine lite was on, however, now it's off, I still show codes on scanner....
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vote
1answer
139 views

How can I estimate CO2 emissions for a vehicle travel distance [closed]

How can I properly estimate CO2 emissions for a given travel distance (of a private vehicle)? I found the following formula, but I'm not sure that it's correct: kgCO2 = Average fuel consumption per ...
1
vote
1answer
194 views

Check Engine Light for bad gas cap [duplicate]

I am just wondering... a friend told me that a faulty gas cap can cause air in the tank.. is that true? also, can that cause the check engine light to come on?
1
vote
1answer
4k views

Replaced 02 sensors, engine light still on

I recently bought a second hand VW Golf. It was 'serviced' and MOTed before the guy sold it to me. He said three 02 sensors were replaced during the servicing. The day I drove it away, the engine ...