High Idling

[big_kev]

Hi folks

I have checked through the forum for answers around my issue and none of the answers seem to relate to what i have found. Her is the scenario,

When the car has just been started and is cold the car will idle perfectly at around 800 rpm. This continues until the car gets warm enough to engage the first level of the heater fan. When the internal fan comes on at level 1 the revs then rise to around 1200 rpms. If i was to switch off the fan altogether then the engine revs drop once again to 800. The AC button can be active or not it does not make a difference, it is only the heater fan in the car that makes this happen. This does not apear to be anything to do with the temperature of the engine as this happens even after a couple of hours run.

If anyone has come across this problem before i would be interested in hearing from them. Again i will say that this is nothing to do with the engine temperature and electric chokes and CATs etc.

IS220D 06 plate

Regards

Kevin

[big_kev]

Should have said guys that this is on an IS220D 06 PLATE.

[juicestop]

Hi folks

I have checked through the forum for answers around my issue and none of the answers seem to relate to what i have found. Her is the scenario,

When the car has just been started and is cold the car will idle perfectly at around 800 rpm. This continues until the car gets warm enough to engage the first level of the heater fan. When the internal fan comes on at level 1 the revs then rise to around 1200 rpms. If i was to switch off the fan altogether then the engine revs drop once again to 800. The AC button can be active or not it does not make a difference, it is only the heater fan in the car that makes this happen. This does not apear to be anything to do with the temperature of the engine as this happens even after a couple of hours run.

If anyone has come across this problem before i would be interested in hearing from them. Again i will say that this is nothing to do with the engine temperature and electric chokes and CATs etc.

IS220D 06 plate

Regards

Kevin

This is quite normal, its not a problem. With the AC on from a cold start, the heater sensor knows it isn't yet warm enough to blast the air through. As the engine heats up the blower levels rise and in turn require more power, hence the revs rise to provide more power to the Battery to supply the higher levels of AC. Of course when you switch off the AC the revs will drop again as there is no need to power the AC. When the AC temp setting is reached, the blower (if on auto) will subside and the revs will drop down to a more normal rpm.

[Matus]

This is quite normal, its not a problem.

With the AC on from a cold start, the heater sensor knows it isn't yet warm enough to blast the air through.

I agree, it is normal.

As the engine heats up the blower levels rise and in turn require more power, hence the revs rise to provide more power to the battery to supply the higher levels of AC.

no, it has nothing with lack of power.

For example, when it is -2°Celsius, the AC on AUTO doesn't work (unless you force it) and the idle is still high.

Of course when you switch off the AC the revs will drop again as there is no need to power the AC.

no, try it. The only way to put idle to normal is to switch of the fan (blower), not AC.

When the AC temp setting is reached, the blower (if on auto) will subside and the revs will drop down to a more normal rpm.

the revs go to normal with AC and fan on when coolant temperature level reaches about 90% of standard temperature.

During warm days it sometimes went down also at about 70% of standard temperature, so may be this is also one of conditions to correct the idle, but in my car it is usually when 90%.

[big_kev]

Thanks guys

Matus your summary of my situation is correct. The AC is does not require to be on for this to happen. The engine revs will rise if only the internal heater fan is on the first setting, not necessarily with the AC on.

just to eliminate the idea that the car is drawing more power so requires to rev higher. I can turn on every electrical device in the car (Rear heater, front defog, heated seats, radio, window wiper defrost, lights) all at once and the car will still not require to idle any higher. As soon as the internal heater fan becomes active the revs rise.

I have heard that some of the motor manufacturers are examining the idea of using the same electrical wire to perform or manage different pieces of equipment by using different frequencies and pulses. Could this be one of the problems of cross talk over differing wires or am i on completely to wrong track?

I am a little concerned that i am going to encounter problems in the summer when the car is trying to cool itself down and the engine is reving to high.

Kevin

[Matus]

I have heard that some of the motor manufacturers are examining the idea of using the same electrical wire to perform or manage different pieces of equipment by using different frequencies and pulses. Could this be one of the problems of cross talk over differing wires or am i on completely to wrong track?

do you mean CAN BUS, or something newer?

I am a little concerned that i am going to encounter problems in the summer when the car is trying to cool itself down and the engine is reving to high.

Kevin

well even after short drive on motorway the engine quickly goes to operating temperature and car will idle on 750-800rpm.

Anyway, in any case, you switch off the fan for minute-two and turbo will cool down ;-)

[SP33DY]

I can confirm this as well, I get exactly the same thing as you have described.

I only saw this after my ECU firmware was updated 2 months ago.

[Denis Ivanov]

As you guys already mentioned this is programmed in the ECU and this is the engine warm-up program. If it bothers you just turn off the ventilators as I do and the car will idle at 750-800 :) It blows cold air anyway (I don't have the additional air heater) until it reaches working temperature.

[Matus]

don't you have the "power heater" button on the lefthand lower side?

[Denis Ivanov]

Nope. I don't have that. It takes forever for the car to warm up and the winters in Bulgaria are cold :)