What is the reason why the old Jetta caught fire from the throttle after starting?

Engine ignition 1 post-tempering. The mixture is too thin, 2. There is something wrong with the ignition system, 3. Ignition advance angle is too large, 4. There is too much carbon on the valve. Failure of fuel supply system or air intake system; The failure of the oil circuit is mainly caused by too little fuel injection from the injector. The reasons are as follows: the oil pressure is too low; The fuel injector is blocked. The failure of the air intake system is mainly caused by excessive air intake, which is caused by the following reasons: (1) the sensor controlling the air intake fails; Air leakage in the intake manifold. 2. In the case of insufficient ignition energy or spark plug failure, the ignition system will fail. 3. Improper CKP clearance, loose CKP, temperature sensor damage, engine load, ECU damage, etc. It will also cause an excessive ignition advance angle. If there is something wrong with the car, ask the car master. 4S shop professional technician, 10 minutes to solve.