A hard cold engine starting up

If the ambient temperature is above -5℃, each engine start can last for 5 seconds, the maximum attempts are three times for cold engine starting up, indicating the engine start is normal. With car technology improved, cold engine starting up is not difficult, but we recommend the cold engine starting up is less than 5 seconds.

The reasons of a hard cold engine starting up 

(1) Starting system failure, such as battery power shortage, starter damage or starter circuit fault. 

(2) Engine mechanical failure, such as air intake pipe leakage, piston and cylinder sealing is lax, valve closure is lax, intake valve and intake pipe carbon deposit too much, resulting in absorption by carbon deposit when the air-fuel mixture is injected into the combustion chamber.

(3) Engine management system faults, such as weak speed sensor signal, incorrect coolant temperature signal, poor circuit contact, etc.

(4) There are faults in the ignition system, such as excessive carbon deposit of spark plug or the gap is wrong, high voltage wire leakage, ignition coil failure,etc

(5) Failure of the fuel supply system, such as insufficient fuel pressure, leakage or blockage of the fuel injection nozzle, etc.

Cold engine shaking at idle

If the cold engine and the hot engine shake simultaneously while idling, first, we should eliminate the fault of the hot engine shaking. Observe whether the engine tachometer pointer is swinging, or read the engine speed. The damage of the engine pad will also cause engine shaking, especially when the automatic car is shifted forward gear.

Common cause of engine vibration at idle

(1) Engine mechanical failure, such as the cylinder pressure is not uniform.

(2) Intake system failure, such as intake pipe leakage; too much carbon deposits in the intake valve and intake pipe; too much dirt on the inner wall of the throttle valve and intake pipe, etc. 

(3) Engine management system faults, such as incorrect coolant temperature, intake temperature signal, circuit fault, etc.

(4) There are faults in the ignition system, such as excessive carbon deposit in the spark plug or the gap is wrong, high voltage wire, distributor cap leakage, ignition coil damage.

(5) Failure of the fuel supply system, for example, the injection nozzle is closed loosely or blocked due to excessive carbon deposit on the nozzle.

Cold car accelerates badly

Although many car manufacturers' user manuals indicate a cold engine start doesn’t need to warm up, but we recommend you to warm up your car for three to five minutes, especially in cold weather, it will reduce mechanical wear and tear of the engine and make the engine more powerful for low-emission car. 

The reasons for poor acceleration of cold car are as follows

(1) Engine mechanical system failure, such as low pressure in the cylinder leading to engine power decline, especially when the engine start.

(2) There are excessive carbon deposit on the intake valve and intake pipe. As a result, the air- fuel mixture is absorbed by the carbon deposit and hard to get into combustion chamber;

(3) Engine management system faults, such as incorrect coolant temperature, intake temperature signal, circuit fault, etc. 

(4) There are faults in the ignition system, such as too much carbon deposit in the spark plug or the gap is wrong, high voltage wire, distributor cap leakage, ignition coil damage; 

(5) Failure of the fuel supply system. For example, the injection nozzle is closed loosely or blocked due to excessive carbon deposit on the nozzle.