Why does the Audi A6L shake at idle when cold?
1 Answers
Audi A6L shaking at idle when cold is mainly due to insufficient temperature inside the engine, inadequate temperature of fuel and lubricating oil, uneven cylinder pressure, excessive carbon deposits on intake valves and intake pipes, and excessive carbon deposits inside the fuel injector nozzles. The reasons for Audi A6L cold idle shaking are as follows: 1. The engine temperature is too low, and both fuel and lubricating oil are at low temperatures. During cold starts, a richer air-fuel mixture is required, which in turn demands higher ignition energy. Excessive spark plug gap, aging ignition coils, and high-voltage coils can all lead to reduced ignition energy, causing the car to shake. 2. Uneven cylinder conditions cause engine shaking. In multi-cylinder engines, significant differences in ignition energy among cylinders, as well as varying degrees of wear on pistons and piston rings, result in inconsistent compression ratios. This leads to uneven power output from the engine, manifesting as engine shaking. 3. Incorrect air-fuel mixture ratio causes shaking. During cold starts, if certain engine sensors or some sensor signals have significant errors, the ECU may make incorrect judgments. This results in inaccuracies in fuel injection timing and ignition timing control, leading to engine shaking.
