market dynamics
The maintenance record of the bad start of the cold car of the electric jet motorcycle
Release date:2020.09.28

According to the owner, his car cold car start is particularly difficult, need to start two or three times to get the car, and the first start after the car, the car immediately shut off, need to start again once or twice to get the car, this time the car is normal.

Then even if you turn off the electric door lock and turn off the fire, restart everything will be normal, will not turn off by themselves.

After the car was picked up, inspection was carried out and it was found that the fault light was not on and the sensor did not pick up any fault that could be stored, indicating that there should be no obvious component damage. Repairmen know that the more ambiguous a fault is, the harder it is to detect.

It is understood that his fault is due to the cold weather not to ride, park three or four months later riding again in.

Having been sitting there for months, I had reason to be suspicious of gasoline in the first place. When he ran out of the same tank of gas, he refilled it with a new one, and the problem continued.


Let's comb through his car's problems: one is that it's hard to start when it's cold, and the other is that it stalls when it's idle.

First check the valve clearance, check the intake valve and exhaust valve clearance are normal.

Then we check the atomization of the fuel injector, based on the fact that the car has not been running for 3 to 4 months.

Remove the fuel injector fixing screw, remove the fuel injector, open the electric door lock, when the gasoline pump was working to establish the initial oil pressure, the "z" sprayed the gasoline everywhere, scared me. It's too dangerous.

The fuel injector in this car was sealed with a sealing ring in the middle of the fuel injector, which was pressed against the inlet by the fixing screw of the high pressure oil pipe.

Then press the nozzle with your hand against the high pressure tubing, and then try to press the start button and observe the fuel coming out of the injector -- well atomized. This indicates that the fault has nothing to do with the nozzle.

At this time, the owner provided a piece of information. When the car was running at about 60, there was a rush and the feeling of the accelerator could not be added, so the accelerator response was relatively slow and needed a sharp accelerator. Only after the car turned 60, the speed could be increased sharply.

So, this could indicate that the throttle body needs to be cleaned or that there is something wrong with the throttle position sensor.

Remove the throttle body and clean it. Indeed, the throttle body is relatively dirty.

At the same time it was found that there was some tarry dirt on the intake manifold and the right hand cleaned it. Check the stepper motor and so on all work normally, and then install the throttle body reset.

During the maintenance, I found a detail that the throttle position sensor mounting hole is long round, which means you can try to make some adjustment to the left or right on the throttle body.

After the throttle body is installed and reset, loosen the fixing screw of the throttle position sensor, and then adjust the throttle position sensor to the "open direction" first. Start the empty car to do the refueling experiment; Then adjust the throttle position sensor to the "less open direction" and start the car again for the fuel test.

Empty car test, the feeling does not have too big difference, that ride road test. Judging from my experience, his car is likely to be a failure point with many different manifestations. That is to say, it is a fault, causing the cold car is not good to start, idle speed is easy to turn off, driving a crash and other fault performance.

He solved the problem of driving at a fast pace, his cold car would not start well, idling would stall easily, and so on.

Also, the car had trouble starting when it was cold. Don't forget -- it takes less than a minute for a cold car to get hot. It takes two or three hours for the hot car to get cold. So it's a lot more time to check and drive than it is to start a cold car.

Try setting the throttle position sensor to the "least open" position, then hit the road for a road test -- and you won't feel a jerk around 60 MPH.

When you get back, put the throttle position sensor in the "maximum open" position to make it more visually noticeable. And then we did the same experiment -- although the top speed was still 80, now the car's power performance was significantly improved.

Then he did a third experiment, put the throttle position sensor back in its "original" position, and then did the same experiment on the road -- the power was still strong. And 60 or so per hour and there is no "kick" feeling.

Let the owner try riding, various riding tests, there are no more problems, the owner is satisfied. The next step is to see if the problem of starting the cold car has been solved. I put the car in the shop and the owner went to work. After he came back from work, he tried to start the car.

The owner picked up the car and went away. The next day, he called me and told me that the car was back to normal. It started smoothly in the morning, and there was no abnormality during the whole day's cycling.