(1) cold car acceleration car
Although many road-sweep car manufacturers ' manuals indicate that the cold car can be started without warm-up after starting, I believe that if the road-sweeping car engine can be warmed up for 3 to 5 minutes after starting, it will be of great benefit to the road-sweeping car engine. . Because this can reduce the mechanical wear of the sweeper engine, the small-displacement sweeper engine can provide sufficient starting power. If the rapid acceleration after the start of the cold car will be a slight drag phenomenon, if the brake phenomenon is serious, the fault is generally due to: 1 sweep the car engine mechanical system failure, such as low cylinder pressure caused by the engine power of the sweeper car, in the cold The status is more prominent. 2 Excessive carbon deposition on the back of the intake valve and in the intake pipe causes the injected gasoline to be absorbed by the coke and cannot enter the combustion chamber. 3 Faults of the engine management system of the road sweeper, such as incorrect water temperature, intake air temperature signal, and line fault. 4 There is a fault in the ignition system, such as too much carbon deposit in the spark plug or improper gap, leakage in the high voltage line, distributor cover, and damage to the ignition coil. 5 oil supply system failure, such as the injector internal colloidal carbon deposition caused the injector to close or clogged.
(2) cold car is not easy to start
The road sweeper repair standard stipulates: In the ambient temperature above -5°C, each time the starter is used for 5 seconds, the engine shall be started up to a maximum of three times. With the improvement of the technical content of road sweepers today, many users have long denied this standard. They hope that the use of starters should start successfully within 5 seconds, and modern electric sweeper vehicles can generally do so. If a trouble occurs when the engine of the sweeper vehicle starts to be difficult, the cause of the malfunction generally includes: 1 A failure of the starting system, such as insufficient battery power, damage to the starter, or failure of the starter circuit. 2 Road sweeper engine mechanical failure, such as air intake pipe leakage, poor sealing between the piston and the cylinder, and lax valve closing result in low cylinder pressure. (3) Excessive carbon deposition in the back of the intake valve and in the intake pipe causes the injected gasoline to be adsorbed by coke and cannot enter the combustion chamber. 4 Faults of the engine management system of the road sweeper, such as weak speed sensor signal, incorrect water temperature signal, and bad line contact. 5 There is a fault in the ignition system, such as too much carbon deposit in the spark plug or improper gap, leakage in the high voltage line, and damage to the ignition coil. 6Failure of the oil supply system, such as insufficient pressure in the fuel system, leakage or blockage of the fuel injector.
(3) Idle speed jitter of cold sweeper engine
When the sweeper engine cold starts, if the sweeper engine does not have a cold idle or unstable speed, the cause of the failure generally includes: 1 The mechanical failure of the sweeper engine, such as the low pressure of each cylinder. 2 intake system failure, such as air intake pipe leakage. 3 intake valve on the back and the intake pipe too much carbon. 4 Sweeping car engine management system failures, such as water temperature, intake air temperature signal is not correct, the line is faulty. 5 There is a fault in the ignition system, such as too much carbon deposit in the spark plug or incorrect gap, leakage in the high voltage line, distributor cover, and damage to the ignition coil. 6 oil supply system failures, such as the fuel injector internal colloidal carbon deposit caused the injector shut down or blockage.
2. Failure Countermeasures
The diagnosis of the above three faults shall be performed in accordance with the principles of power-on and power-off, and simple and complicated operation. If there is a “three-heat fault†in the engine of the sweeper vehicle, the hot-vehicle cannot be started easily, the hot-vehicle idle jitter and the hot-vehicle acceleration are poor. Should be ruled out first. The diagnostic procedures are as follows: 1 Check the appearance of the engine of the sweeper and check whether the vacuum tube and the harness plug are detached, and if there is leakage, leakage, oil leakage and water leakage. 2 Use the scan tool to check the fault code and data flow. 3 Use multimeters, oscilloscopes, and other devices for measurements. 4 Based on the above checks to determine the cause and parts of the fault, repair or replace the accessories. 5 Use the above equipment again after troubleshooting. 6 Reproduce the occurrence of failure conditions to test or road test.
The reason for the “three-cold†failure of the EFI car is mostly the back of the intake valve and too much carbon in the intake pipe, and there are too many impurities inside the injector.
If the above three kinds of faults occur on new vehicles, such as vehicles with a mileage of less than 60,000 km, it is recommended that users clean the engine of the road sweeper truck every time the road sweeper runs 2 to 30,000 km. The two items “dialysis†and “drip†should be performed at the same time because the former is effective for cleaning injectors, and the latter is effective for cleaning carbon deposits on the back of the valve. The bottle's flow should be controlled well, the cleaning time should be controlled at 20~30min, some cleaning agent can be inhaled at idle speed, and the washing machine can be turned off to increase the rotation speed to soften a layer of coke. The ratio of cleaning agent to gasoline for dialysis is 1:5. The cleaning capacity for lean cleaning is poor, and over-concentration will cause waste.
In addition, the sweeper engine should be driven at a higher speed (above 80km/h) for more than 20km after free-removal cleaning, so that the melted colloid and coke burn out from the tail gas at high temperatures. If the road sweeper is placed on the morning of the second day after completion of the disassembly-free cleaning, the valve will be melted and the glue will stick. It will be more difficult to start and the engine of the sweeper vehicle will idle more quickly. This is the so-called “sticky valveâ€. phenomenon. Once this phenomenon occurs, it is necessary to re-free wash.
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