A Jianghuai and Chang che (model HFC6512A4AC8F). Customer response: when the car starts or has low gear, the fuel smell is very strong. Fault diagnosis: closing the window for a long time, the fuel smell is very strong. Check the charcoal canisters and their pipelines without damage; check the fuel tank, one-way valve and fuel tank cover, etc., there is no leakage. Considering that the total mileage of the car is about 60 thousand km, it is doubted that the fuel vapor adsorbed by the activated carbon tank is saturated, that the fuel vapor is leaked through the vent of the activated carbon tank, and the leaked fuel vapor is sucked into the car, so the fuel is very strong in the car. After changing the activated carbon tank to test the car, the failure is still. Open the hood of the engine room after starting and low gear. The fuel smell is very strong. Check the intake manifold carefully and find the crankcase of the inlet manifold is cracked. The analysis shows that the vacuum degree varies greatly in the intake manifold, so that more gas mixture leaks from the cracking of the crankcase forced vent. Troubleshooting: replace the crankcase with forced ventilation pipe, test the car's fuel smell, and remove the trouble.