What would a high HC low CO and high o2 at the same indicate?

Asked By: Olvido Hornberger | Last Updated: 11th March, 2020
Category: automotive green vehicles
4.7/5 (626 Views . 16 Votes)
General Rules of Emission Analysis
Remember, CO readings are an indicator of a rich running engine and O2 readings are an indicator of a lean running engine. High HC, high CO, and high O2 at same time indicates a misfire due to excessively rich mixture.

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Likewise, what causes high HC and CO?

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.

Subsequently, question is, how do you reduce HC emissions? Lean burn spark engines are a promising technique to further reduce both NOx and hydrocarbon/carbon monoxide (HC/CO) engine emissions. Higher lean burn levels improve HC/CO oxidation while simultaneously reducing NOx formation. The NOx reduction is due to cooler flame temperatures.

In respect to this, what does high HC ppm mean?

A high HC reading means the test found high HC (hydrocarbons) in your emissions. In other words, too much gas is left in the exhaust after combustion.

What are the 3 most leading failures of a catalytic converter?

Check out these three common causes of catalytic converter problems.

  • Unburned Fuel. Heat can be damaging to almost any engine component, so it's no surprise that it's one of the most common causes of catalytic converter failure.
  • Coolant Leaks.
  • Oil Consumption.

18 Related Question Answers Found

How do you cheat emissions?

We will discuss those methods below.
  1. 6 Proven Methods for Passing an Emissions (Smog) Test:
  2. Warm up Your Car's Engine as Much as Possible.
  3. Use a Fuel Additive.
  4. Be Sure Your Tires Are Inflated to the High End of the Range.
  5. Change Your Oil Before Your Smog Check.
  6. If Your Check Engine Light Is On, Find a Way to Turn It off.

What causes CO emissions failure?

Carbon Monoxide is a by-product of incomplete combustion. Carbon Monoxide exceeding maximum limits, can be due to a number of emission failures ranging from inadequate air intake to defective engine computer sensors. This condition is referred to as a "Rich Fuel Conditon".

What is HC ppm Emissions test?

Hydrocarbon Emissions
Emissions are measured in parts per million, or ppm, and a higher release of hydrocarbons from a vehicle can cause a failed smog test. For example, in the state of California, the maximum hydrocarbon parts per million is 64 when the test is run at a simulated 15 miles per hour.

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.

Can spark plugs affect emissions?


Change your spark plugs and check your spark plug wires: Worn or fouled spark plugs, as well as worn spark plug wires can result in less-than-stellar results on your emissions test. And it's the only spark plug recognized by the EPA (Environmental Protection Agency) as an emissions control device.

What is ppm in emission?

Hydrocarbons are raw fuel,also known as Gasoline. High Hydrocarbon (HC) emissions are always a sign of poor fuel ignition. PPM is the Parts per million:It is used to measure quality performance,this is done by many customers today. 1 PPM= one (defect or event) in a million or 1/1,000,000.

What causes emission problems in a car?

These are 4 of the most common reasons a car will fail an emissions test.
  • Bad O2 Sensor. If your oxygen sensor malfunctions it can not properly monitor the exhaust and may cause additional problems such as overheating, loss of engine power or poor acceleration.
  • Rich Fuel Mixture.
  • Bad Fuel Metering.
  • Faulty EVAP System.

Will retarding timing reduce NOx?

The engine-management system does its best to limit NOx production by carefully regulating the air-fuel mixture and ignition timing. Retarded timing reduces engine performance, fuel economy and emissions.

How do I lower my NOx levels?

NOx Emission Reduction Strategies
  1. by Marc Karell and Amit Chattopadhyay.
  2. Fuel switching. Fuel switching is the simplest and potentially the most economical way to reduce NOx emissions.
  3. Flue-gas recirculation (FGR).
  4. Low NOx burners.
  5. Derating.
  6. Steam or water injection.
  7. Staged combustion.
  8. Fuel reburning.

What is HC in pollution?


Types of emissions. Emissions that are principal pollutants of concern include: Hydrocarbons (HC) - A class of burned or partially burned fuel, hydrocarbons are toxins. Hydrocarbons are a major contributor to smog, which can be a major problem in urban areas.

How do I fix my emissions?

How to Fix Emissions Problems On a Car
  1. Check the air filter on the air cleaner system.
  2. Inspect the Positive Crankcase Ventilation (PCV) system.
  3. Examine the Evaporative Emissions Control (EVAP) system.
  4. Go over the Exhaust Gas Recirculation (EGR) system.
  5. Check the Air Injection System if your particular vehicle model is equipped with it.

Will an oil change improve emissions?

Cleaner Emissions
Reducing this exhaust, or emissions, is good for the environment, and helps you pass your dreaded emissions test. With regular oil changes, you not only reduce greenhouse gas emissions and do your part to help the environment, but, you can be sure you will pass your emissions test without worry.