What causes high idle speed in a hot Santana?
2 Answers
The reason for high idle speed in a hot Santana is due to the idle switch not closing and the idle contacts being disconnected. The solutions are as follows: 1. Check the throttle opening. If the basic idle speed is too high, inspect the vacuum sealing of the system, especially the sealing of the vacuum tube, PCV valve, and related parts of the crankcase. 2. Check the engine load signal. If the idle control valve opening is too large, verify whether the engine load signals are normal, such as the air conditioning signal, battery voltage, and the temperature value of the water temperature sensor. 3. Check the vacuum degree of the intake manifold. During normal engine idle conditions, the vacuum degree of the intake manifold should be 57~71kPa. If the vacuum degree is too low, it will cause abnormal pressure signals in the engine intake system, leading the engine computer to mistakenly assume an increased load and thus raise the idle speed.
I've been driving for many years, and this issue is quite common with old Santanas. A sudden increase in idle speed when the engine is warm is mostly caused by carbon buildup in the throttle body. That time after being stuck in city traffic, my car's idle speed jumped to 1500 RPM, buzzing annoyingly, and I thought it was an electrical problem. Later, upon inspection, it turned out the throttle body was dirty, and after cleaning the carbon deposits, it returned to normal. It could also be due to a clogged air filter restricting airflow, making the engine struggle and increasing idle speed; or a faulty coolant temperature sensor sending false cold-engine signals to the ECU, causing it to raise the RPM. These issues can lead to a spike in fuel consumption and shorten the engine's lifespan, especially worsening after long-distance driving. I suggest fellow car owners regularly clean the throttle body and replace the air filter every season to prevent problems, ensuring safer and more worry-free driving. Don’t ignore idle speed issues—it could lead to big trouble at critical moments.
