How to diagnose the engine’s a few cylinders does not work fault?

Start the engine, gradually increase the throttle, from low speed to high speed during the entire exhaust muffler can hear the rhythmic "sudden, sudden" sound, and with the engine speed increases, the "sudden, sudden" sound the frequency also increases, can be determined that the engine does not work with a small number of cylinders.

Determination of a cylinder does not work, should replace the spark plug first, then check the high-pressure penny is off. If no shedding, testing method applied in the high voltage short circuit to determine which cylinder not working with a screwdriver, namely the spark plug short-circuit, and observe the change of the engine speed. If a cylinder spark plug short-circuit, engine speed decreases significantly, the cylinder is normal; if the speed slightly, to the cylinder side; if there is no change of speed, the cylinder does not work.Check the ignition system, the best ignition oscilloscope, oscilloscope in no case, check the available methods are as follows:

If a cylinder does not work, should unplug the cylinder high-pressure line, at a distance of 5 7mm around the spark plug, observe whether there is a fire, if no fire, or will the cable at the other end of the distributor Jack pulled out a little, see if Jack jump to a line. If the jump, is the junction leakage.

If there are two cylinders does not work, unplug the two-cylinder sub-cylinder line, about 5-7mm from the spark plug, check for spark. If both flash over, but no change in engine speed, it may be sub-line two-cylinder two-cylinder spark plug wrong or do not work. Remove the two cylinders cents if not spark, or a flashover one does not flash when the cylinder is not working should be a way to check inspection.

Without the work of two cylinder distributor cap next to the jack adjacent to unplug a cylinder cents, about 5mm from the spark plugs checked arcing condition. If there is no fire or the fire is weak, it should be of wire-bound back, unplug the other cylinder sub-line, check the flashover conditions, such as the same is no fire or fire is weak, then the two-point line while the cylinder body arcing and so that the two sub-line distance from the cylinder block nearly always a distant one, if what the root sub-line close, what the root flashover, you can certainly for the two-point line where the jack cylinder channeling electricity.

If the pressure line to the spark plug and spark plug spark strong, good, should check whether caused by mechanical failure of the engine.The electronic ignition engine, must use the oscilloscope, the fire is the test of the use of such methods cannot. In addition, if the spark plug fouling serious, there may be excessive wear caused by the engine, you must first rule out the fault for further examination.

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