What is no ppm in the smog test?
Nitrogen Oxide or NO is created when an engine’s combustion chamber temperature reaches over 2500F.
What Causes No ppm to be high?
Combustion temperatures increase causing high nitric 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.
What is HC ppm?
Find “HC PPM” within the tailpipe section. You read this as hydrocarbon parts per million, and it means the number of hydrocarbon molecules for every million molecules emitted through the exhaust.
How can I lower my HC emissions?
On a precomputer carbureted car, one way to get under the HC and CO limits is to retard the ignition timing. This will slow the idle and provide a longer, hotter burn. Then, bring the idle speed back up to specs with the throttle stop screw or idle stop solenoid, which will admit more air.
Why is NOx so bad?
Nitric oxide (NOx) NOx can cause serious health damage to humans, including respiratory diseases. NOx is also responsible for smog and the typical brown cloud that covers larger cities and produces poor air quality. NOx reacts with volatile organic compounds in the presence of sunlight and forms ground-level ozone.
Can a bad O2 sensor cause high NOx?
High NOx emissions can occur when an engine’s air-fuel mixture is too lean. This could be caused by a problem with the vehicle’s oxygen sensor, malfunctioning air flow and coolant sensors or a leak in the fuel system.
Does a catalytic converter reduce NOx?
Catalytic Converters – Non-Selective Catalytic Reduction System. For proper operation of a NSCR system, the combustion process must occur with an air/fuel ratio slightly fuel-rich of stoichiometry. In the presence of the catalyst under this condition, NOx is reduced by the CO, resulting in nitrogen and carbon dioxide.
Why are my hydrocarbons too high?
There are still many possible causes of high hydrocarbons, most of which are either internal engine problems or tough-to-detect induction system problems such as valve deposits or a leaking EGR valve. On fuel-injected vehicles, poor fuel atomization is a common cause of HC problems.
What causes high HC on smog test?
What causes high HC emissions? Excessive HC results from ignition misfire or misfire due to excessively lean or rich air/fuel mixtures.
How do you cheat a smog test?
6 Proven Methods for Passing an Emissions (Smog) Test:
- Test a very warm car on a cool day.
- Use a specialized fuel additive.
- Inflate tires to the proper (high) level.
- Perform an oil change.
- Turn off your “Check Engine” light (if needed).
- Find a shop that offers a free retest.
What causes high HC at idle?
Ignition defects including dirty spark plugs, leaking or open-circuited spark plugs or wires, or defective ignition coils can all result in a shortage of spark energy. Any shortage of spark energy may cause high HC emissions. If the spark occurs at the wrong time, incomplete combustion and high hydrocarbons may result.