Fuel supply system malfunction

進氣管出現回火是由燃油供應不足，混合氣過稀引起?；旌蠚膺^稀使混合氣燃燒速度減慢，燃燒一直延續排氣行程終了進氣門開啟的時候，新鮮混合氣遇到氣缸內未排凈的燃燒氣體而被點燃，并逆流經進氣歧管從進氣口噴出而回火。

The occurrence of backfire in the intake pipe is caused by insufficient fuel supply and a lean mixture. The mixture is too lean, which slows down the combustion speed of the mixture. The combustion continues until the exhaust stroke ends. When the intake valve opens, the fresh mixture encounters the combustion gas that has not been completely discharged from the cylinder and is ignited. It then sprays out from the intake port through the intake manifold and backfires.

點火系故障

Ignition system malfunction

進氣管出現回火是因為點火過晚或火花質量差。一方面使開始燃燒的時刻推遲；

The occurrence of backfire in the intake pipe is due to late ignition or poor spark quality. On the one hand, it delays the start of combustion;

另一方面也會使燃燒速度減慢，從而導致燃燒一直延續到進氣門開啟，引起進氣管回火。同時伴隨的現象還應有：發動機加速時轉速提高緩慢，急加速時回火現象明顯，有時緩加速時也有回火現象，同時排氣管排氣聲發悶，發動機溫度易升高。

On the other hand, it can also slow down the combustion speed, leading to combustion continuing until the intake valve opens, causing the intake pipe to backfire. At the same time, accompanying phenomena should also include: slow increase in engine speed during acceleration, obvious backfire phenomenon during rapid acceleration, and sometimes backfire phenomenon during slow acceleration. At the same time, the exhaust sound from the exhaust pipe is muffled, and the engine temperature is prone to rise.

如果在進氣管回火的同時，機體抖動嚴重，排氣管放炮，發動機功率嚴重下降，則多是由點火錯亂而引起的。由于點火錯亂，當某缸處于進氣行程進氣門開啟，恰好該缸火花塞點火，則會形成進氣管回火。

If the engine shakes severely, the exhaust pipe bursts, and the engine power drops significantly while the intake pipe backfires, it is mostly caused by ignition misalignment. Due to ignition misalignment, when a certain cylinder is on the intake stroke and the intake valve opens, and the spark plug of that cylinder ignites, it will form a backfire in the intake pipe.

如果檢查確認各缸分高壓線沒有插錯，則多為分電器蓋擊穿。需要引起注意的是分電器蓋存在輕微擊穿時，一般情況下發動機在無負荷空轉時工作正常，但在熱車重負載爬坡時有回火現象，且回火時動力明顯下降。

If it is confirmed that the high-voltage lines of each cylinder are not inserted incorrectly, it is mostly due to the breakdown of the distributor cover. It should be noted that when there is a slight breakdown in the distributor cover, the engine generally works normally when idling without load. However, there is a phenomenon of backfire when climbing a hot vehicle with heavy loads, and the power significantly decreases during the backfire.

如果發動機空轉時工作正常，急加速或急減速時有時回火；高速行駛時有不規則的回火現象；在不平道路上行駛時回火頻繁，對于傳統有觸點點火系來說多因分電器搭鐵不良，對電子點火系來說可能是點火器等搭鐵不良或點火系某傳感器松動等。搭鐵不良的分電器或點火器當發動機振動較大使分電器搭鐵時，相當于低壓回路斷開，產生高壓電。若分火頭正好指向某個處于進氣行程的氣缸，則會引起進氣管回火。

If the engine operates normally while idling, and sometimes backfires during sudden acceleration or deceleration; Irregular tempering phenomenon during high-speed driving; When driving on uneven roads, frequent backfire may occur. For traditional ignition systems with contact points, it is often due to poor grounding of the power distributor. For electronic ignition systems, it may be due to poor grounding of the igniter or a loose sensor in the ignition system. A poorly grounded distributor or igniter. When the engine vibrates heavily and the distributor is grounded, it is equivalent to a disconnection of the low-voltage circuit, generating high-voltage electricity. If the ignition head points directly at a cylinder in the intake stroke, it will cause the intake pipe to backfire.

對于無分電器雙缸同時點火的點火系來說，急加速時出現回火現象還有一個常見的故障原因，那就是火花塞不良。在

For ignition systems with dual cylinder ignition without a distributor, a common cause of backfire during rapid acceleration is poor spark plug. stay

檢查高壓線無漏電、斷路后，試換火花塞不失為上策。

After checking that there is no leakage or open circuit in the high-voltage line, it is still best to replace the spark plug.

機械故障。

Mechanical failure.

如果發動機低速運轉時進氣管回火。排氣管有“突突”聲，轉速提高后癥狀減輕，則應檢查某氣缸壓縮壓力比正常值是否低0．2MPa以上。若將此缸斷火，回火現象消失，則說明該缸進氣門密封不嚴。電于進氣密封不嚴，該缸作功時，燃燒的高溫氣體便會通過進氣門進入進氣歧管，引起進氣管回火。因為發動機轉速提高后，氣門的相對漏氣率降低，因此回火現象在低速時明顯，高速時減輕。

If the intake pipe backfires when the engine is running at low speed. If there is a "popping" sound in the exhaust pipe and the symptoms alleviate after the speed is increased, it is necessary to check whether the compression pressure of a certain cylinder is lower than the normal value by more than 0.2MPa. If the cylinder is turned off and the tempering phenomenon disappears, it indicates that the intake valve seal of the cylinder is not tight. When the intake seal of the electric cylinder is not tight, the high-temperature combustion gas will enter the intake manifold through the intake valve when the cylinder is working, causing the intake pipe to backfire. Because the relative leakage rate of the valves decreases as the engine speed increases, the phenomenon of backfire is more pronounced at low speeds and less pronounced at high speeds.

如果發動機工作時，連續有節奏地出現回火，同時動力下降某缸斷火后，回火現象消失，則多是因為該缸排氣門調整螺栓松脫或推桿折斷，使該排氣門無法開啟或開度過小。由于排氣門不能完全開啟，使得該缸廢氣不能及時完全排出，在進氣門開啟時，尚未排出的高溫廢氣便進入進氣歧管，引起進氣管回火?？捎脭喔追ㄕ页龉收细?，然后打開氣門室蓋，檢查該缸排氣門螺栓及推桿是否異常。

If the engine experiences a continuous and rhythmic flashback while working, and the flashback disappears after a certain cylinder is shut off due to a decrease in power, it is mostly because the exhaust valve adjustment bolt of the cylinder is loose or the push rod is broken, making the exhaust valve unable to open or opening too small. Due to the incomplete opening of the exhaust valve, the exhaust gas in the cylinder cannot be completely discharged in a timely manner. When the intake valve is opened, the high-temperature exhaust gas that has not yet been discharged enters the intake manifold, causing the intake pipe to backfire. The cylinder failure method can be used to identify the faulty cylinder, then open the valve cover and check if the exhaust valve bolts and push rods of the cylinder are abnormal.

如果發動機工作時，進氣管連續回火，低速時更明顯，相鄰的兩缸中某缸斷火?；鼗瓞F象消失。則可能是因為相鄰兩缸之間的氣缸墊燒穿。因為相鄰兩缸之間的氣缸墊燒穿，使某缸做功時，燃燒著的混合氣進入相鄰氣缸，若此時這個缸的進氣門處于開啟狀態，則會形成進氣管回火?？捎脭喔追ㄕ页龉ぷ鞑涣嫉膬蓚€氣缸，檢查兩缸的配氣機構，如電控失調或元件及線路有故障，也會導致混合氣過稀，進氣管回火放炮。

If the intake pipe continuously backfires while the engine is operating, it is more pronounced at low speeds, and one of the adjacent cylinders misfires. The phenomenon of tempering disappears. It may be because the cylinder gasket between adjacent cylinders is burned through. Because the cylinder gasket between adjacent cylinders burns through, when a certain cylinder does work, the burning mixture enters the adjacent cylinder. If the intake valve of this cylinder is in an open state at this time, it will form a backfire in the intake pipe. The cylinder cut-off method can be used to identify the two cylinders that are not working properly, and to check the valve distribution mechanism of both cylinders. If the electronic control is out of control or there are faults in the components and circuits, it can also cause the mixture to be too thin, and the intake pipe to backfire and explode.