Fault phenomenon
    An Accord passenger car with a mileage of 23890km. The engine is worn out or when the brake is braked.
    Troubleshooting and troubleshooting
    First with Honda dedicated detector HDS engine control unit for testing, no fault code. Read the data stream is not found abnormal, and the engine in idle conditions running smoothly. In order to determine the fault, the author made the following routine inspection: the throttle body and the idle valve was cleaned after the test, the fault remains the same. The fire plug of the car also made a check, did not find abnormal; then I use the oil pressure gauge to detect fuel system oil supply pressure normal (normal fuel pressure 270kPa ~ 320kPa). The failure only in the rapid acceleration or braking when the time, according to experience this failure out of the ignition system is more likely. As the car's high-voltage line and ignition coil is one of the occasional accident probability is not high, so the replacement of the throttle body and idle motor, but the fault remains the same. Check the line, found in the throttle next to the inlet on the ground line of a virtual connection (shown in Figure 1).
    Will be re-processing of the wire re-processing after the test, troubleshooting.
    Maintenance summary
    It is known from the maintenance data that the ground wire here is the ground of the ignition control module. Due to poor connection here, when the vehicle in the rapid acceleration and braking when the engine before and after the large shaking, resulting in ignition control module ground contact bad and off the fire, resulting in engine jitter.
    Expert reviews
    The car is not complicated, but from the troubleshooting process, the author is still a lot of trouble, why is this? This is actually our fault in the previous comments in the many mentioned "definition" problem. From the solution to the case we can see that the author did not give an "accurate definition" of the failure, but to get the car after the so-called detection, of course, some testing is necessary, but our detection can not be no purpose, Not defined. The failure of the car is "in the rapid acceleration or step on the brake when the engine jitter", there are two levels: one is the failure occurred in the vehicle when the rapid changes in the situation; one is the engine jitter. First define the "engine jitter" problem, because "when the rapid acceleration or step on the brake" is only "engine jitter" conditions. The engine jitter should first detect whether the engine is "missing the cylinder", such an accidental or dynamic fault, the detection must be in the dynamic state of the vehicle, check the fault state of the relevant data, if we are defined as "engine jitter" , Then we will be in the dynamic state to detect whether the "lack of cylinder." At this time we can use dual-channel or multi-channel oscilloscope detection of fuel injection and ignition and the main signal waveform monitoring, to see the case of failure, fuel injection waveform, ignition waveform (although the car using single-cylinder independent ignition, The spark plug is directly connected to the ignition coil and has no ignition high voltage line in the middle, and the ignition coil is bolted to the cylinder head and the bolt is used as the ignition coil, but the modern ignition oscilloscope has a special detection tool to detect its waveform) Whether the sensor signal is interrupted, of course, including the ignition control module on the cylinder ignition coil control signal. The car through the monitoring we can find that when the vehicle jitter, the ignition waveform will be intermittent interruption, which can determine the fault from the ignition system, which can quickly reduce the scope of the fault, you can avoid unnecessary replacement parts. As the maintenance personnel in the troubleshooting, there is no precise definition of the fault, troubleshooting becomes no way out, fault detection has no purpose, resulting in the wrong replacement parts, especially the replacement of the idle control valve operation can not understand.
    In addition, the failure occurs in the "rapid acceleration or step on the brake", such a change in the conditions caused by the failure of the majority of the line is bad or broken ground caused by grinding, can cause the engine performance is drastic changes in the majority Electronic control module power lines and grounding lines, as well as the main sensor and actuator control lines. This is a lot of fault experience, so in the event of such a failure, still pay attention to the monitoring of the fault and the above parts of the inspection. For the exclusion of such a failure, Mr. Tang Jianping "Aveo intermittent flameout" a very useful reference.
    The failure of the article is not detected, but accidentally discovered, such a troubleshooting can not help but feel a bit "luck" of the composition, and this troubleshooting is tiring.
    The car's fault is defined as "acute acceleration or brake braking when the engine jitter serious" some wrong, according to the final point of failure and failure of the mechanism: ignition control module grounding virtual connection → ignition control module intermittently stop working → each Cylinder ignition coil are intermittent loss of ignition control signal and intermittent fire → engine intermittent moment to stop working → engine speed intermittent instantaneous decline → the engine on the vehicle to produce "engine brake", we can see the car fault should not be "Engine jitter".