Some car friends reflect that the vehicle can not start, the most basic inspection operation will, such as unplug the high voltage wire jump fire, see if there is a high pressure fire. But if you have a high pressure fire, you have oil, but you don't have a car, you don't know how to check further.
Today we arrange a high pressure fire weak case, for reference.
This is a 125 straddle motorcycle, the engine cold start is difficult, each start to struggle for a long time, is really tiring, the owner of the car to me here maintenance inspection, to see what is the cause.
After receiving the car, first test to determine the fault, first open the ignition key, press the start button, check the start circuit. After pressing the start button, I feel the starter is very powerful, and the engine has a kind of half-awake feeling, but it just can't start to fire.
The experienced ones know that when the starter won't drag, the foot starter may work. Then he put his foot on the starting lever and, with great effort, started the engine to catch fire.
The cause of engine cold start difficulty is usually related to the fuel system, ignition system can not work properly.
Unplug the high voltage wire from the spark plug, rotate and unscrew the high pressure cap, hold the high voltage wire to the engine body and keep a distance of 7~8 mm for high pressure fire test, test and confirm that there is no fire at high pressure.
Right NOW CANNOT ARBITRARILY THINK WITHOUT SPARK, SHOULD gradually shorten the distance OF high voltage line to cylinder body, when the distance is shortened to 4 mm or so, high voltage line just produced weak high voltage spark to engine body.
The test results show that the ignition system fault is the cause of the engine starting difficulty failure.
This situation is the first suspect of igniter, look at this is an AC car, so replace the same type of electronic igniter, the result is the same problem.
Then I replaced the high voltage package, but it still didn't work. By this time, the magneto coil should be the focus of suspicion.
Disconnect the connecting wire of the charging winding in the magneto cable harness. Since no peak voltage converter is configured on the maintenance site, the AC peak voltage output of the charging winding cannot be detected. Therefore, the AC voltage output of the charging winding can only be detected by the AC voltage range of the multimeter.
Press the start button to make the engine rotate statically. The reading of the multimeter is 35V. Then use the ω file of the multimeter to detect the resistance value of the charging winding. The resistance value of the charging winding is about 80 ω lower than the normal value (340 ω), and the coil is obviously faulty.
Maintenance DianPenChe friend, sometimes felt so mysterious about data streams, the following figure, don't know how to see, actually the displayed data stream is some testing data, such as the above paragraph, the voltage resistance value you can be regarded as a kind of data flow, thumb estimate, will know that there is something wrong with the data, this can help us to locate fault.
Electric spray truck is the same, fault maintenance tools are always auxiliary, effective or brain and experience.
Since it is determined that the coil charging winding is faulty, it can only solve this problem. Since the charging winding is only used for AC igniter, it is too troublesome to change the coil, and the AC igniter is not as stable as the DC igniter. From the maintenance cost, it is better to change the DC igniter to save time and reduce future problems.
This kind of old car, change performance good digital igniter, control and speed can also be improved, the owner prefers. The DC igniter I choose is "Taichang intelligent Point", which basically does not need to consider the matching problem of the model, and can be used when connected.
Remove the AC electronic igniter from the cable harness, replace the "Tai Chang wise point" igniter with the corresponding jack, disconnect the black/red wire in the cable harness, and change a separate red line inside the igniter plug to the ignition key DC power lock out of the wire, it is very convenient. This red line is the power cord. In addition to the power supply after the lock, it can also be connected to the positive wire of the flasher or brake switch. The effect is the same.
After modification, the hand-held high voltage wire to the engine body and maintain a distance of 7~8 mm, high voltage jump test, press the start button, high voltage wire to the cylinder block immediately produced a strong high voltage ignition spark.
Screw the high voltage wire on the high pressure cap, install the spark plug, press the start button, the engine is ready to ignite, smooth start and fire, difficult to start the fault smoothly eliminated.
On the road test, feel the throttle state, the engine issued a low roar, speed up significantly faster than the original.
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