Bad start and acceleration m104.980
(Sorry for the repost) Hi everyone, I’d like to talk about an issue I’ve had with my car (M104.980) ever since I bought it. It has always suffered from starting problems, hesitation during acceleration at low speeds (both hot and cold), and a lack of power when cold. The car had massive vacuum leaks coming from the injectors, the KE-Jetronic boot, and the air hoses. Everything has been replaced, and the system is now completely airtight. The ECU was replaced, along with the temperature sensor, potentiometer, idle control valve, fuel accumulator, and check valve (which was causing extremely long, 10-second crank times). The duty cycle is set to 45–50%. Before replacing all these parts, the power loss and hesitation were much worse. When cold, it starts immediately but either stalls or runs very roughly (stuttering) for 3–4 seconds. Also rarely if it doesn't fire up instantly but takes 2–3 seconds of cranking, it starts perfectly. When cold, there is significant hesitation, sometimes dead spots (no response), and very low power. These symptoms disappear as the engine warms up (to 80°C); once hot, it regains full power. However, I still experience random stuttering under load at low speeds or in neutral, as shown in the video—sometimes it's mild, sometimes intense; it's unpredictable. Hot starts are much better, though if I let the car sit for about 10–15 minutes before starting it again, it stutters for 1–2 seconds.