What is the issue when both 4H and 4L lights are on simultaneously?

What Causes Engine Shaking When Warm but Not When Cold?

The reasons and solutions for engine shaking when warm but not when cold are as follows: 1. First, use an automotive diagnostic tool to check for any engine fault codes. If present, identify the faulty sensor and perform the necessary repairs; 2. If there are no engine fault codes, check for any engine misfires. If misfires are detected, inspect the spark plugs, ignition wires, ignition coils, crankshaft position sensor, and ignition coil circuits. Perform the necessary repairs or replacements; 3. If no misfires are detected, inspect the fuel supply system. Remove the fuel line and connect a fuel pressure gauge for a pressure test. A normal reading should be between 270Kpa and 350Kpa. If the fuel pressure is low, inspect and repair the fuel pump as needed; 4. If the fuel supply system is functioning properly, check if the throttle body is clean. If it is dirty, clean it thoroughly with carburetor cleaner. Then, check if the idle air control valve is working. If it is not functioning, replace it; 5. If the throttle body and idle air control valve are functioning properly, inspect the fuel injectors for proper operation or blockages. If the injectors are not working or leaking abnormally, check the injector wiring and perform the necessary repairs; 6. If the fuel injectors are functioning properly, check the compression of each cylinder. A normal compression reading should be 8 or higher. If the compression is insufficient, take the vehicle to a repair shop for the necessary repairs.

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Why is the car idling high?

The main reasons for high car idle speed are: 1. Excessive carbon buildup in the throttle body, which reduces engine air intake, causing the ECU to increase throttle opening to raise RPM; 2. Air leaks at the rear of the throttle body, allowing outside air to enter the engine and increase RPM; 3. Generator failure causing the ECU to increase RPM; 4. Damage to the throttle body itself or the idle speed control valve. Specifically, the reasons for high car idle speed include: 1. Excessive carbon buildup in the throttle body. This carbon buildup forms over time from the intake system as air contains impurities like dust. When carbon buildup is significant, the throttle's opening and closing resistance increases, and engine air intake decreases. Reduced air intake can cause stalling, so the ECU increases air intake and adjusts the throttle opening to prevent stalling, naturally raising the idle speed. 2. Air leaks at the rear of the throttle body, usually caused by aging or cracked intake manifold gaskets or damaged vacuum hoses. Since the rear of the throttle body is in a negative pressure vacuum zone, leaks allow outside air to be drawn into the engine. When the ECU detects increased air intake, it increases fuel injection, raising idle speed. 3. Generator failure. When engine RPM remains constant, the generator load increases with additional electrical devices. If the ECU detects the generator is not producing electricity, it assumes the engine RPM is too low and commands an increase in idle speed. 4. Damage to the throttle body or idle speed control valve. A faulty potentiometer inside the throttle body affects the throttle opening size, and a larger opening leads to higher idle speed. The idle speed control valve regulates idle speed, and if it fails, idle speed will also increase. Correspondingly, solutions for high car idle speed include: 1. For excessive carbon buildup in the throttle body, use carburetor cleaner to remove the carbon deposits and then recalibrate the throttle opening. Be careful to avoid spraying cleaner into electrical connectors to prevent damage to internal electronic components. 2. For air leaks at the rear of the throttle body, use a smoke leak detector to locate the leak and then repair or replace damaged gaskets or vacuum hoses. 3. For generator failure, use a multimeter to check if the generator's output is within the normal range. If not, replace the faulty generator. 4. For damage to the throttle body or idle speed control valve, replace the throttle body or idle speed control valve. Finally, it is normal for idle speed to be high during a cold start (for a very short duration). This helps the engine reach optimal operating temperature quickly, improving fuel efficiency and protecting the engine. If idle speed remains high after the engine warms up, check for issues like throttle carbon buildup.

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What are the differences between the Fit and Polo?

Both the Honda Fit and Volkswagen Polo are classified as compact cars. Here are the key differences between them: Space and Dimensions: The Fit measures 4100×1695×1525mm (L×W×H), while the Polo measures 3970×1682×1462mm. In terms of interior space, the Polo may be slightly inferior to the Fit. Powertrain: The Fit is equipped with a 1.5L engine paired with a CVT transmission, delivering a maximum power output of 96kW. The Polo comes with a 1.5L engine mated to either a 6-speed automatic or 5-speed manual transmission, with a maximum power output of 81kW.

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What Are the Design Standards for Automotive Superchargers?

The purpose of supercharging is to increase engine power and enhance engine stability by pre-compressing air before supplying it into the cylinders, thereby improving the intake air quality and correspondingly increasing the cycle fuel supply. Functions of turbochargers: Enhance engine power performance, improve engine fuel economy, reduce engine emissions, and provide altitude power recovery through the self-compensation function of turbochargers. Basic types of superchargers: There are three types: turbocharging, mechanical supercharging, and pressure wave supercharging, corresponding to turbochargers, mechanical superchargers, and pressure wave superchargers.

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What is a temporary license plate?

Temporary license plates are paper motor vehicle license plates that allow temporary road use, issued by the vehicle management department of the public security authority for newly purchased vehicles before official registration. The validity period of temporary plates generally does not exceed thirty days, and there are four types: temporary plates for administrative jurisdictions, temporary plates for cross-administrative jurisdictions, temporary plates for testing purposes, and temporary plates for special-type motor vehicles. Two temporary plates should be affixed simultaneously: one in the upper right corner of the front windshield inside the vehicle, in a position that does not obstruct the driver's view and is not covered by the compulsory traffic insurance label; the other should be affixed in the upper left corner of the rear windshield inside the vehicle.

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What Causes the Abnormal Noise When Accelerating a Car?

Reasons for abnormal noise when accelerating a car: 1. Excessive clearance or damage in internal engine components such as pistons, valves, gears, and camshaft bearings; 2. Loose or insecure connections in areas like door panels, glove compartments, air vents, and center console panels causing friction; 3. Rusty brake discs or noise caused by trapped sand and debris; 4. Loose shock absorbers or connecting components in the suspension system. Engine maintenance methods include: 1. Regularly changing engine oil and oil filters; 2. Periodically using high-efficiency rapid cleaning agents for the lubrication system to clean the crankcase and maintain internal engine cleanliness; 3. Regular maintenance of the PCV system, removing contaminants around the PCV valve to ensure proper crankcase ventilation.

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What is the issue when both 4H and 4L lights are on simultaneously?

What Causes Engine Shaking When Warm but Not When Cold?

Why is the car idling high?

What are the differences between the Fit and Polo?

What Are the Design Standards for Automotive Superchargers?

What is a temporary license plate?

What Causes the Abnormal Noise When Accelerating a Car?

Do You Need AC for Car Air Conditioning in Winter?

What is the normal value of an automotive air conditioning pressure gauge?

What Type of Engine Oil Should Be Chosen for RAV4?

The Formula of Vehicle Urea and How to Mix It