What Causes High Idle Speed in Nissan X-Trail?
1 Answers
Reasons for high idle speed in Nissan X-Trail: Idle switch not closing: The rotation speed signal determines the fuel injection volume and injection timing. However, when the engine is operating under idle conditions with reduced air intake, it leads to an overly rich air-fuel mixture and consequently increases the rotation speed. Faulty idle control valve: When the idle speed exceeds the set value, the ECU commands the idle control valve to reduce the intake bypass passage, thereby decreasing the air intake and lowering the engine speed. Issues such as sticking of the idle control valve due to oil contamination or carbon deposits, or incomplete closing of the throttle valve, can prevent the ECU from properly adjusting the engine idle speed, resulting in unstable idle conditions. Intake manifold leakage: The opening of the idle control valve and the air intake strictly follow a specific functional relationship, meaning that as the idle control valve opens wider, the air intake increases accordingly. Intake manifold leakage disrupts this strict functional relationship between the air intake and the idle control valve opening. The air flow sensor cannot accurately measure the true air intake, causing the ECU to inaccurately control the air intake and leading to unstable engine idle speed.
