Questions tagged [emissions]

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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On carbureted vehicles, are vacuum lines exposed to gasoline vapors?

I'm restoring a 1985 Chevy G30 Van 5.7L, but these questions apply broadly to carbureted vehicles. The vehicle is carbureted, and most controls for the emissions system and climate control system are ...
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Exhaust gas composition from London buses

I asked this on Reddit earlier this week, but nobody had much technical insight. Can anyone shed light on why exhaust gas from a typical London bus smells entirely different from a coach or truck's ...
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High HC emissions, CO & NO is ok

I have a 95 Isuzu Rodeo with 3.2. the HC readings are 63 @15mph & 44@ 25mph. I did an oil change, replaced the plugs, wires, 02 sensor, and put in different fuel additives with each gas fill-up. I ...
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Did I get the right catalytic converter for my Honda Odyssey?

There is an engine code on the bank 2 catalytic converter in my 2007 Honda Odyssey EX-L, I paid for a diagnosis from a mechanic and they recommended replacement of the bank 2 catalytic converter. I ...
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1996 Ford F150 (OBD2) fails AZ emissions due to "disabled" EVAP

My 1996 F150 with OBD2 is failing Arizona emissions due to disabled EVAP system. I did not disable it and don't know how it would have been disabled. There is an EVAP canister present though. The ...
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'16 Mazda CX-5 failing HC-PPM emissions test?

I have a 2016 mazda cx-5 with 25K miles that has to go through a yearly inspection. The vehicle's in good shape, plus I take it the mazda dealer for maintenance. I took it to the the inspection center ...
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Chemical analysis to detect oil burning in emissions [duplicate]

Is it possible to chemically analyze an engine's emissions to detect presence of oil in the fuel? I am losing a lot of oil but it's not dripping when running to indicate a leak. So I would like some ...
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What are the factors that rev hang depend on? Does rev hand depend on the engine load?

I know that rev hangs are intentionally introduced to modern vehicles that operate on electronic throttle bodies, by programming the ecu to close the throttle valve slowly (in gasoline engines) even ...
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EGR was deleted. Is this the EGR line?

Someone who owned my 1986 3.8l Mustang before me decided to delete the EGR system. I'm attempting to get this car to pass emissions so I want to reinstall the EGR system. However I want to make sure I'...
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High voltage on downstream O2 sensor after driving, but low voltage on idle

After driving on the highway, my downstream O2 sensor voltage was a steady 0.8V, which is high. On the other hand, when idling before the drive, it was a steady 0.3V. Is it normal for the downstream ...
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What kinds of tuning can ruin a car's ability to pass emissions testing?

Suppose I want to tune a car for performance, like doing an ECU re-map for a Toyota Supra. Could this affect the car's ability to pass emissions testing? If so, how? And in general, what kinds of ...
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Options? Stripped out Threads on a Catalytic Converter-Mounted 02 Sensor in California

This is a multi-part question: First, I would like general input on how a catalytic converter should be evaluated for signs of failure? For example, does testing a CAT to ensure it doesn't have ...
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2012 Automatic Civic firing wrong

I had a question for you all if you'd please help me out. My 2012 automatic civic had its emissions light, VSA light and high temperature lights turn on after I scraped the back rear end on a curb. ...
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P0491 Secondary Air Injection System Insufficient Flow. Stumped

My VW CC 2010 is having a CEL with the code P0491 which means the pressure sensor is not detecting enough air being pumped from the intake into the exhaust. No other codes. No problems since this is ...
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Emission High CO and High Lambda

It fails at 2500rpm only with CO 0.5~0.6 and Lambda 1.04~1.05. How can it possible be that emission fails because of HIGH CO, and HIGH lambda reading... It means that engine runs rich and lean at the ...
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Inspection Not Ready ( 02, 02 heater, cat)

2006 Ford F150 Battery was unplugged before car was purchased. I bought it and put 300+ miles on it and still see those 3 sensors not ready. No codes. Replace all 02 sensors? Diagnose with mech for ...
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Will replacing spark plugs fix this? [closed]

My husband and I purchased a 2011 Mazda 6 2-3 months ago. It had 71,000 mi on it when purchased. One accident, but only cosmetic. A few weeks after driving it, I noticed some jerking when coming from ...
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What is this inlet part on a lawnmower muffler?

I have noticed a small box on the bottom of the muffler on a Mountfield SV150 lawnmower engine. Inside is a reed valve set up as inlet only and a small filter grill. What is the purpose of this part? ...
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Catalytic Converter Clogged, But with what?

So, I've recently replaced my catalytic converter, bank 1 and 2. Both were a pretty penny (About $1,500 Each), I inspected the old catalytic converters and they look to have failed due to being ...
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Volkswagen GTI OBDII Readiness

I have a 2015 Volkswagen GTI SE (2.0T) which is (a little over) due for an emissions test. A few weeks ago I had some rear-end bumper damage repaired, and while in the shop they cleared the trouble ...
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Can anyone provide documentation for the 2011 chevy cruze eco grill shutters?

I'm trying to understand how they work and where the motor is since I am unable to get the plastic off the bottom of the grill to access them directly. Mine seem to move if I slowly torque them ...
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Where does California publish vehicle emission standards?

When a vehicle is smog tested in California, several components of its exhaust gas are measured. If the levels of those exhaust gas components are within limits (presumably established by California)...
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Over filled oil - 09 Hyundai Elantra

I dropped off my car for an oil change which is an older model, but I always took care of it so it ran great. I listen to the vehicle all the time to ensure nothing seemed off, and no issues. The ...
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What is CO2 g/km emissions equivalent of Euro 4 petrol standard?

I am trying to find what Euro 4 standard is with regards to CO2 g/km. All I can find is that it is: CO: 1.0g/km THC: 0.10g/km NOx: 0.08g/km This makes no sense to me when trying to compare this to e....
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What should I expect as result of a firmware update fixing NOx emissions in a gasoline engine?

I received an invitation from Peugeot asking me to bring a 2018 naturally aspirated gasoline engine Peugeot 208 (61 kW) to the workshop for a firmware update fixing lamba sensor management which ...
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Evap System Leak, Repair and Clear Codes to Pass USA State Emission Inspection?

I'm aware of two related issues here Does Check Engine Light Clear Itself... I need the correct 2010 ... drive cycle steps to clear a “Permanent ” P0456 code I've just completed a particularly nasty ...
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MOT emissions fail

My mini 1.4 petrol has failed on high co and hc but only by a small amount . Last year I gave it a service to pass the emissions but this year it’s not having it. I have fully serviced it, added a ...
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Incereased HC in emission test, low CO VW Jetta 1.4 TSI

Yesterday I took my 2008 VW Jetta (1.4 TSI 122ps with 101k km) for annual emissions test. The car passed the test but I noticed that an increment in HC from year to year, especially when idling (...
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Georgia Emissions Testing Missing Gas Cap "Evap Emission Control Sys Leak Detected (Small Leak)"

I lost the gas cap for my 2008 BMW 328i about a month ago. It took me about a week to get it replaced. During that time, the check engine light for my car lit up. I went out of town right after ...
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Converting emissions readings between ppm and g/km

Having taken my wife's 20 year old Nissan in for it's MOT test last week, I was looking at the results of the emissions test, and noticed that the Hydrocarbon reading was 6ppm - with a limit of 200. I ...
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CO and Lambda fail after cleaner, air filter and throttle body clean

Went for an MOT, first test failed on high CO AND HC but normal lambda. Got new air filter, cleaned EGR and throttle body and added a cat cleaner into petrol tank. Second MOT failed due to high CO (...
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Is it possible for an oxygen sensor spacer to cause a car to stall?

VW CC 2010 2.0L CBFA I installed an O2 sensor spacer on my downstream O2 sensor and it seemed to be working for a day. One day later, after the car had cooled down it would rough idle and stall when i ...
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My truck failed emissions because they couldn't find the EGR

I just took my 2011 GMC Silverado 2500 w/Duramax in for an emissions test in Utah County. They do more than just emissions test. They look to make sure all the elements of the emissions system are in ...
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Emissions - High CO Reading

My 2004 Volkswagon Polo has just failed its emissions test. It has failed on the CO only, everything else is okay. The results are as follows: Engine/Oil Temperature: 92℃ (720 RPM) Low Idle CO 0.32 ...
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Emissions reading on a 1993 Toyota Corona/Carina E 3SFE 2.0

Are these values normal for a 1993 car? If not, please tell me what should be fixed or replaced. I believe it's running rich based on the lambda value.
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Low idle after adding gasoline

This has happened twice now. My 2000 toyota sienna runs fine until I went to add gasoline. Upon startup, my idle was immediately much lower. I can rev throttle and it sounds smoothly until I release ...
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What can cause "check gas cap" warnings other than a loose gas cap?

I have a 2006 Saturn Ion, and a few months ago I started getting a warning about my gas cap. Specifically, as I was driving the dash display would beep and say "Check Gas Cap." I bought a new cap to ...
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2012 Mazda 5: P0422 Code

My 2012 Mazda 5 Grand Touring has been having the following problem. Sometimes it takes an extended amount of time to start and other times it will crank normally, but then sputter and stall. When ...
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Cannot hold constant RPM on Neutral with accelerator pedal

Having Chrysler Town & Country 2008 with 4.0L gasoline engine. Is it normal that i'm not able to keep engine at 2k RPM for 10 seconds? After some seconds, it just climbs itself up to 3k, but i'm ...
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Hi CO Emissions - Kial Soul+ 2.0L

My 2012 Kia Soul+ (53,700 miles) failed the emissions test for high HC and high CO at high RPMs (2500). After a new air filter, spark plugs, a professional injector and throttle body cleaning, the ...
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92 Toyota P'up Smog Test Fix?

My'92 Toyota P'up runs great, has had thorough annual maintenance since purchased new, & odometer is now at 166,500 miles. My last smog check indicated that the M1: 15 MPH "HC" (PPM) MEAS was 95, ...
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Check engine light : code p0455. Idling below 1,000 rpms losing Acceleration power at times and engine dies randomly

Car is a 2009 Chevy impala. Engine code p0455 is the only code my car shows. I have already had a vent solenoid replaced. It was the one by the gas tank that was about a year ago now. No issues ...
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What is exhaust gas recirculation?

From what I understand, EGR is used to reduce the temperature of combustion without increasing the amount of fuel injected to reduce NOx emission. This is done by reducing the oxygen percentage ...
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Does anyone know the OEM for the 2006 Infiniti qx56 oxygen sensors

I've got the part numbers and some cross references for the 2006 Infiniti QX56 oxygen sensors, but I would like to buy from the OEM. Bosch? Denso? infiniti front left/right 226937S000 bosch 17204 5 ...
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What could be causing High HC GPM, CO GPM, prevent the RPM from going over 4000, and creating an odd exhaust sound?

I have a Toyota Camry 94, it failed its emission test today with 2.62 HC GPM(Limit is 1.2) , 56.87 CO GPM (Limit is 15). The car also won't rev over 4000 RPM and acts as if it has a governor on when ...
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Car shakes upon startup, dies. Other times gas pedal does not respond

I'm pretty uneducated when it comes cars but im hoping you guys can help me. I have a 99 Ford Ranger that upon startup (not every time) shakes extremely hard and then dies. Other times when driving I ...
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High CO Emissions

My Yaris is due for an MOT this month. The last MOT report says that CO is right on the limit, everything else is normal HC, Lambda etc., as shown below. The CO has been creeping up every year, and ...
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Emissions check engine light on a Honda Civic

Would a dirty air filter trigger a check engine light "Check Emission System". It is intermittent and seems to come on while driving on the highway when the ambient temp is below 0 C. Any ideas or ...
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Engine grease fell into combustion chamber

I was changing a spark plug out on a 2000 Ford Expedition with a 5.4L Triton, with the coils on the plugs (COP), and I'm worried about how dirty it was. I was being as careful as possible, but I know ...
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Check emission system displayed on dashboard display

For the last week it has been extremely cold where I live (varies between -27 to -33 degrees Celcius). Is it possible for a fuel cap check valve to freeze open? Last night leaving work the display ...
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