Failure phenomenon: a 2009 annual Accord 2.0 L sedan, mileage 11000 km. According to reflect the user when the vehicle in normal driving on the highway, the engine suddenly fault light is lit, and then the accelerator pedal does not work, until a parked vehicle to restart the vehicle, the vehicle can not be started properly.
Analysis Check: After I pick, the first user authentication failure phenomena. Turn the ignition switch, normally found in engine failure lamp goes out, attempts to start the vehicle, it does not start normally. I suspect that the spark plug has been ldquo; rdquo ;, then drowned disassembly inspection of the spark plug 4, cue, four spark plugs were all gasoline ldquo; drowned rdquo ;. Cleaning four cylinders and a spark plug installed after retest vehicle, the vehicle can barely start, the engine idle instability, jitter badly, engine failure soon lamp light, and the accelerator pedal is depressed, engine fault light flashes, the engine rotation speed It did not improve.
FIG 1
I HDS connection failure diagnostic detection, the retrieved fault code PGM-FI (FIG. 1), then observe the data block, We found a significantly higher number of misfiring cylinders. This indicates a bad working cylinders, possible reasons include: fault injectors, spark plug failure, cylinder pressure is too low, the ignition coil failure, line failure, and associated with poor fuel quality and the like. Due to disassemble the spark plug has been previously checked and found no problems, so you can rule out the possibility of the spark plug failure. So I first the four ignition coil ldquo; flashover rdquo; test and found good ignition of each cylinder, the ignition coil can exclude the possibility of failure. Is 1-cylinder injector out of the question? After the author with questions cylinder injector 1 with two cylinder injector test interchanged, or find fault code indicating a misfire cylinder, which cylinder injector 1 described is also no problem.
2
by asking the user to know the car has been fixed gas station, but just in case, I still use the power of lion instead of gasoline fuel system cleaner experiments carried out with the car, still find fault, but one thing ldquo; unexpected rdquo; case attracted the attention of the author, it is usually normal vehicle idling state,Bottle cleaning agent is capable of burning the fuel system is about 30 min, while maintaining the car but only 5 min. Why car will burn so quickly it? Now the circuit diagram (FIG. 2) that, when the ignition switch is turned ON (II) position, a PGM-FI main relay is energized, and the battery power supply to the engine control unit ECM / PCM, injector and PGM-FI main relay 2. When the ignition switch, a measuring cylinder injector 2 connector pin No. 1 yellow / black lead, voltage 12 V, with the result is normal; measuring the resistance between the No. 2 line and the ground is less than the brown 1Omega ;, Description at this time, No. 2 has a brown grounding line, that is to say a fuel injector in the cylinder when the ignition switch is opened to start the injector; 2-pin connector were measured and the other three cylinders, three found 1 yellow / black wires are battery voltage and not to ground the wire 2. The measurement results show more than a short circuit between the No. 2 cylinder injector brown wire 1 and ground. I also measure the resistance between the lines of this brown cylinder injector from 1 to ECM / PCM C5-connector, the result is less than the wire segment 1Omega ;, indicating that there is no problem. Is it a problem with the engine control unit? In order to validate their own judgment, I replace the engine control unit together with a normal vehicle, the vehicle control unit, with HDS re-match after the car, the fault disappears, smooth engine idling. At this time, the data block was observed and found a cylinder misfire is 0, then return to normal. Road test failure does not occur again.
Troubleshooting: Replace the ECM / PCM, failure to completely eliminate.
reviewed: the failure of the car rarely encountered before, and less likely to malfunction of the engine control unit, so maintenance personnel are generally not first suspected a problem with the control unit. In addition, if the repair process maintenance personnel are not carefully observed, it might ignore the excessive consumption of fuel system cleaning agent of ldquo; unexpected rdquo; situation, so that the entire diagnostic process stalled. This requires maintenance personnel in the course of work must pay strict attention to every detail. Because sometimes a little discovery, can become a breakthrough to solve the entire failure.
(Zhang, Wang red)