Why does my rpm drop when I turn on my AC?

Why does my rpm drop when I turn on my AC?

The idle speed initially drops because the A/C Compressor is driven by a belt connecting it to the crankshaft and requires some of the engine’s power to drive it. Most vehicles, however, have a mechanism to detect this rpm change under the A/C Compressor load and will bring the rpm back to normal.

When does RPM drop when a / C compressor engages?

The rpm drop only occurs when any A/C component is on (A/C, defroster, or re-circulation), when just the vent is on, the rpm does not drop and the engine run fines. Please help me with this question, it seems like this is not a one of a kind problem.

Why does my car turn off the AC at normal cruising rpm?

If your TPS is not not sensing the position of your throttle properly, it will definately turn off your AC at normal cruising RPM. My car does that when I am trying to floor the paddle but in normal mood, it keeps cooling even at 120+ km/hr.

Why does the engine stop cooling at 3000rpm?

The ” stops cooling at 3000rpm ” is exactly what @Anarach stated, in that the clutch disengages above this to allow more power to the engine. It could also do this so as to not over spin the A/C compressor. If you’re engine is hitting the 3000rpm at 100kph, this is probably the reason.

When does the a / C compressor engage, the engine stalls?

When the A/C compressor engages at idle in park or neutral every five to ten seconds the idle drops and will either almost stall the engine or occasionally does stall the engine. This happens in drive as well, and when driving, since the rpm’s drop and come back up, the vehicle surges at low speeds.

The rpm drop only occurs when any A/C component is on (A/C, defroster, or re-circulation), when just the vent is on, the rpm does not drop and the engine run fines. Please help me with this question, it seems like this is not a one of a kind problem.

What happens when engine RPM drops below 800?

However, when the engine RPM drops below the normal range of 800 RPM (for most cars), it is more than likely that you are dealing with an IAC valve problem. In cases where this valve is clogged or is failing, your vehicle will stall instead of slowing to an idle after the release of the throttle.

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.

What causes the engine to slow down at idle?

What actually happens is that the A/C compressor clutch kicks in so that the drivebelt attached to the A/C compressor pulley wheel is then presented with the additional load required to rotate the compressor internals that circulate the refrigerant. This additional load placed on the engine causes the idle speed to slow down.

Posted In Q&A

Why does my RPM drop when I turn on my AC?

Why does my RPM drop when I turn on my AC?

The idle speed initially drops because the A/C Compressor is driven by a belt connecting it to the crankshaft and requires some of the engine’s power to drive it. Most vehicles, however, have a mechanism to detect this rpm change under the A/C Compressor load and will bring the rpm back to normal.

How often does engine RPM drop when idle?

The engine stays idling at about 1000 RPM. However every now and then it drops down to about 500 RPM and then quickly back up to about 1200 then goes slowly down to 1000 and stays there for a bit until I go again or it drops again. It only happens for a second or two and about 3 times a minute.

Why does the idle speed drop when the a / C compressor is on?

Tap to check for your leaks. The idle speed initially drops because the A/C Compressor is driven by a belt connecting it to the crankshaft and requires some of the engine’s power to drive it. Most vehicles, however, have a mechanism to detect this rpm change under the A/C Compressor load and will bring the rpm back to normal.

When does RPM drop when a / C compressor engages?

The rpm drop only occurs when any A/C component is on (A/C, defroster, or re-circulation), when just the vent is on, the rpm does not drop and the engine run fines. Please help me with this question, it seems like this is not a one of a kind problem.

How does the idle speed of a car work?

This valve is controlled by the vehicle’s computer which will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed.

What causes large idle RPM drop from unloaded to in gear?

Idle drop would then be in the 100 RPM range with ‘in-gear’ idle setting coming out @600. A large drop from Unloaded to In-gear idle setting can otherwise usually be attributed to either a vacuum leak or a convertor that’s to ‘tight’ for the engine set-up

Why does my RPM drop when sitting idle at traffic lights?

While I’m sitting idle at traffic lights I put the car into neutral. The engine stays idling at about 1000 RPM. However every now and then it drops down to about 500 RPM and then quickly back up to about 1200 then goes slowly down to 1000 and stays there for a bit until I go again or it drops again.

What causes idle RPM to drop when air conditioner is on?

However, if the IAC is working, then it may be resistance from the AC compressor. This often happens because the AC system leaked out enough refrigerant over the years normally. People let it run without service, then the compressor seizes up ($$).

What happens when engine RPM drops below 800?

However, when the engine RPM drops below the normal range of 800 RPM (for most cars), it is more than likely that you are dealing with an IAC valve problem. In cases where this valve is clogged or is failing, your vehicle will stall instead of slowing to an idle after the release of the throttle.

When the engine is working hard, intake vacuum drops as the throttle opens wide. The engine takes in more air, which requires more fuel to keep the air/fuel ratio in balance. The computer will then retard (back off) ignition timing slightly to prevent detonation that can damage the engine and decrease performance.

Why do my RPMs fluctuate at idle with AC on?

When the engine is put under a load by the AC system, the car’s computer automatically attempts to compensate for that by adjusting the idle. If there is carbon buildup within any part of the system, including the idle air control valve, throttle body, or possibly even the EGR valve, it can cause surging.

The engine stays idling at about 1000 RPM. However every now and then it drops down to about 500 RPM and then quickly back up to about 1200 then goes slowly down to 1000 and stays there for a bit until I go again or it drops again. It only happens for a second or two and about 3 times a minute.

Why does my car idle when the AC is on?

Some times when i put it into drive the the AC on it stays at around 625 RPM’s. It seems to be intermittent mabey… Also i have a good size boost leak in the car, i dont think this will cause my AC problems, but i am fixing it this weekend.

Why does my car vibration get worse at idle?

I have a vibration at idle, and it seems to get worse with the AC on, and a few times when starting the car it sound like it going to die but start to work like normal, my rpm is usually close to the 1 but now it idling at 500rpm due to what I believe is because of the idling issue.

What’s the RPM of my car when the AC is on?

Basically, when i turn my AC on and put the car in drive, my RPM’s drop to about 625 and slowly rise up to 700ish RPM’s. Some times when i put it into drive the the AC on it stays at around 625 RPM’s. It seems to be intermittent mabey…