Symptom: a paragraph Honda Accord sedan (F22B1 engine) on a business trip in the field of small repair shop due to water temperature and high over the cylinder overhaul, overhaul after fairly normal, can be opened back after 3 days: idling sometimes jitter serious, no regular flame And to speed up the failure.
    Failure analysis and troubleshooting: in accordance with the general idea of ​​the first line of maintenance, first read the fault code but no fault code output. Then check the ignition system, set out the high voltage line plug the spark plug, hit the motive found that the spark is very strong, the ignition system should be no problem, open the throttle, found that there are many coke, put the throttle body and idle motor was cleaned. Test, no improvement. Because the car has accelerated the phenomenon of poor, so then pick up the oil gauge oil, oil pressure 240kPa, normal. Gasoline filter is just changed, cleaning the fuel injector, the test, the fault remains the same. At this point can not do anything, decided to use the replacement method, the same model on the idling motor loading test, the fault phenomenon and the original, when the fourth cylinder high voltage line dial, the idling but become stable, the original Idle motor loading, dial the fourth cylinder high-voltage line and just as idling become stable, the fault is not idle motor, will not have a computer problem. Although the car no fault code appears, but can not rule out the possibility of computer failure, decided to use the same model of the computer to try, change the parts after the car, found no change. In the end what is the reason? Will the line is faulty? Take the iron? With these questions on the engine, the body and the computer to check the ground. When checking the engine intake manifold on a ground (near the brake booster), found that the bolt is not tight, the bolt tightened after the car, found that idle speed, smooth and smooth. Because the car is sometimes normal, decided to road test, after more than two hours of road test, everything is normal. Has been delivered for two months, no abnormalities, thus troubleshooting.