Browse

Antiques Collectibles Apparel Baby Kids Items Books， Movies And Music Electronics Free Stuff Garden Outdoor Health Beauty Home Goods Home Improvement Supplies Musical Instruments Office Supplies Pet Supplies Sporting Goods Ticket Toys Games Transportation Others

Used Cars New Cars Others

Business Crafts Design And Web Events Home Improvement Legal Lessons Personal Pets Photography Repair And Technical Support Wellness Writing， Translation， And Transcription Others

Activities & Groups Artists & Musicians Classes & Lessons Events Friendship & Networking Lost & Found Rideshare Sports Teams Volunteers Travel & Travel Partners Skills & Language Swap Other

What does it mean when a vehicle's HC emissions exceed the standard?

1 Answers

GenevieveFitz

07/29/25 3:51pm

When a vehicle's HC (Hydrocarbon) emissions exceed the standard, it indicates incomplete combustion of gasoline, poor atomization, or more seriously, issues with the oxygen sensor or the failure of the three-way catalytic converter in the emission system. Reasons for HC exceeding the standard: 1. Poor engine combustion: Many factors related to engine combustion can contribute, such as the cleanliness of the fuel, the atomization condition of the fuel injectors, fuel pressure, engine compression ratio, cylinder wall quenching effect, faults in the ignition system like spark plugs, ignition wires, and high-voltage coils, and cylinder wear leading to reduced cylinder pressure. 2. Decreased purification capability: Intake system faults can also cause HC to exceed the standard, such as overly rich air-fuel mixture; the fuel evaporation system and the crankcase ventilation system play a crucial role in HC levels.

Was this review help?

19

0

Share

More Forum Discussions

How to solve the P2178 fault code?

Methods to solve the P2178 fault code: 1. The P2178 fault code indicates that the system (air-fuel mixture) is too rich when leaving idle. Possible causes include a faulty mass airflow sensor or manifold absolute pressure (MAP) sensor, excessively high fuel pressure, a faulty fuel pressure regulator, faulty fuel injectors, faulty oxygen sensors, or a faulty electronic control module (PCM or ECM). It is recommended to have the vehicle inspected at a 4S shop before clearing the fault code; 2. A car fault code is a code generated by the vehicle's ECU (Engine Control Unit) after analyzing a fault. Most fault codes are caused by sensor malfunctions or poor sensor performance, but some mechanical faults cannot be read by the ECU; 3. When a car engine develops a fault, a diagnostic tool will display the fault code, allowing the technician to accurately identify the faulty component and proceed with repairs.

What is brake fluid made of?

Automotive brake fluid is composed of castor oil and low-carbon alcohol. Below is relevant information about brake fluid: 1. Brake fluid is a liquid medium that transmits braking pressure in hydraulic braking systems, used in vehicles with hydraulic braking systems. 2. Characteristics of brake fluid: (1) Effectively lubricates moving parts of the braking system: extends the service life of brake calipers and other components; (2) Anti-corrosion and anti-rust properties: non-corrosive to both metal and non-metal materials in the braking system; (3) Adaptability to various environments: ensures flexible transmission of braking force under working conditions such as high temperature, extreme cold, high speed, and humidity; (4) Functions of energy transmission and heat dissipation: serves as a transmission medium.

What does CLK on a car mean?

CLK on a car is a model designation from the German automotive brand Mercedes-Benz. The C stands for Coupe, indicating a focus on style and performance; the L represents Light, signifying agile handling and elegant contours; while the K denotes Compact, reflecting the vehicle's streamlined design approach. Below are relevant details about the CLK: 1. The CLK convertible's soft top perfectly inherits the design of the CLK coupe, offering excellent noise insulation and thermal insulation properties. 2. The standard-equipped bi-xenon headlights with integrated active lighting system in the CLK convertible enhance safety during nighttime cornering. When set to low beam, this system increases road illumination by up to 90% in response to steering inputs.

What Maintenance is Needed at 15,000 Kilometers?

For a car's 15,000-kilometer maintenance, the following items are required: 1. Replace the engine oil and oil filter; if the engine speed is unstable at idle or during startup, a throttle cleaning can be added. Typically, the air filter should be replaced every 20,000 to 30,000 kilometers, and the fuel filter every 40,000 to 60,000 kilometers. 2. Air filter: The engine inhales a large amount of air during operation. If the air is not filtered, the dust in it can accelerate the wear of the piston group and cylinder. Larger particles entering between the piston and cylinder can also cause severe "cylinder scoring." The function of the air filter is to remove dust and particles from the air, ensuring that sufficient and clean air enters the cylinder. 3. Fuel filter: The fuel filter provides clean fuel to the engine, filtering out water and impurities from the gasoline. This optimizes engine performance and provides the best protection for the engine.

What does fault code U1001 mean?

U1001 fault code indicates a communication failure between various computer modules, or it could be a fault in the engine compartment relay control unit. When the U1001 fault code appears, it is necessary to promptly visit a 4S shop for inspection and repair. Communication failure between modules or computer boards is a very serious issue. More details are as follows: 1. Modern vehicles are equipped with numerous electronic devices, and cars are no longer purely mechanical. The abundance of electronic devices means that communication between these devices is essential. 2. Communication between electronic devices in a vehicle relies on CAN bus lines. If communication fails, it could be due to damaged CAN lines or loose CAN line connectors. Additionally, the negative terminals of electrical devices in vehicles are typically grounded. If there is an issue with the negative ground, it can lead to an open circuit.

What is the difference between 4.33 and 4.875 gear ratios?

The rear axle gear ratio of 4.875 compared to 4.33 means that the 4.33 ratio provides higher speed, while the 4.875 offers better power. The 4.875 ratio is more suitable for heavy loads. More details are as follows: 1. The vehicle's transmission serves to change speed and torque. The differential also contains a main reduction gear, which further reduces speed and increases torque. When the engine operates at high RPM, the transmission is needed to lower the speed and increase the torque, enabling the vehicle to run normally. 2. Different gears in the transmission have different ratios, and the main reduction gear ratios in the differentials of different vehicles also vary. A larger gear ratio results in slower speed but greater torque.

Trending Ranking

Why does the tire pressure monitoring system frequently alarm?

What to Do When a Car Blocks the Way Without Leaving a Phone Number?

Does Windshield Washer Fluid Need to Be Diluted with Water?

What brand of tires does the Axela use?

What is the length of a parking space?

Can You Still Drive with a Nail in the Tire?

Is the Volkswagen Phideon an Imported Model?

What are the reasons for low tire pressure displayed in a car?

How to Turn on the Heater?

What is the correct way to check engine oil?

More Forum Discussions

How to Adjust the Time on a Volkswagen Car?

What car has a logo featuring a snake and a cross?

Which city does the license plate 'Lu C' belong to?

How Many Kilometers Should Brake Fluid Be Changed?

Help

Cookie

Cookie Settings

© 2025 Servanan International Pte. Ltd.