Why can't the Audi A6L start when the engine is hot?
2 Answers
The reasons why the Audi A6L cannot start when the engine is hot are as follows: Fuel injector leakage: Fuel injection by the injector is normal, but leakage constitutes additional fuel supply. The more severe the injector leakage, the richer the air-fuel mixture becomes, leading to difficulty in starting when the engine is hot. Damaged carbon canister solenoid valve: During a hot start, fuel atomization is normal and no additional fuel vapor is needed. If the carbon canister continues to supply fuel vapor to the intake manifold, it will cause an overly rich air-fuel mixture, resulting in difficulty starting. Faulty intake air temperature sensor: The intake air temperature sensor adjusts the fuel injection quantity. If it malfunctions, it can cause difficulty in starting when the engine is hot.
The issue of the car not starting when it's hot is something I've encountered many times before, and it's particularly annoying. It could be due to a faulty crankshaft position sensor, where thermal expansion causes signal interruptions. If the fuel injector is leaking, poor atomization is more likely when hot, preventing fuel from entering the cylinders and causing a no-start. Another common reason is excessive spark plug carbon buildup, leading to weak ignition at high temperatures. I tried using a diagnostic tool to read the codes myself, but Audi's electronic system is too complex, and I couldn't figure it out. Later, I found out the ECU software needed an update. My advice is not to mess around blindly; just take it to the dealership for a check. Otherwise, repeated attempts to start can damage the engine and cost even more. Regular maintenance and cleaning the fuel system can prevent this issue, and in summer, especially pay attention to keeping the coolant temperature from getting too high.
