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Why does my rpm go up and down while AC is on?
If the air conditioning is not performing well, the engine might be surging because the system is undercharged or overcharged. If it is overcharged, the load imposed by the compressor will be excessive. If it is undercharged, the AC pressure switch may be cutting the compressor on and off in rapid succession.
Should my rpm fluctuate at idle?
In most of today’s cars, an idle speed of 600 to 1000 RPMs is average. If your car is idling rough, though, it won’t feel smooth. The RPMs will jump up and down, for example, or they’ll fall below 600 RPM (or whatever is typical for your vehicle).
How often does rpm fluctuate with AC on?
After second service at at 6200 Miles, could witness RPM fluctuation between 750 to 960 on idle with AC on. This would happen on a warm summer day. It was happening every few seconds and caused noise and vibrations inside cabin.
What is the normal rpm of a car?
The normal idling RPM is around 820. When idling, I can see the RPM fluctuating between 800-1000 rpm. This fluctuation is more evident when the AC is switched on. I can even hear some loud thud coming from the engine bay (due to the AC compressor) just when I turn on the AC, and along with the sound, the RPMs fluctuates even more.
What should the engine RPM be when idling?
The normal idling RPM is around 820. When idling, I can see the RPM fluctuating between 800-1000 rpm. This fluctuation is more evident when the AC is switched on. I can even hear some loud thud coming from the engine bay (due to the AC compressor) just when I turn on the AC, and along with the sound, the RPMs fluctuates even more. Few points:
What causes rpm to jump back up at idle?
This then causes the RPM to jump back up again and then settle to a comfortable idle speed. You see the same thing to a lesser extent when turning on other systems on the car such as the heated rear screen. It’s most evident with the A/C compressor as this has is one of the biggest drains on the system in terms of additional equipment.