Thread: Aircon loading motor

HI, a certain power loss is normal, some things must be clarified:
1. how much is the initial rpm drop when you switch it on at idle?
2. do you experience the same power loss when you switch the aircon on regardless of outside temperature?
3. make a test, switch the aircon on then when you feel that power loss press ECON button and watch carefully...is there any change then? eventually play with ECON on/off to figure it out...also you can play with temp selection too, to see if there's any change when you select HI (when the compressor must rest) and LOW(when it must kick in)... to select HI/LOW hold both temp selection buttons up or down untill HI or LOW is displayed ... always wait few seconds after each selection to let the system settle ... do the tests at idle, listen to the engine and watch carefully the tachometer

any observed symptoms during these tests are important for the diagnose

do you eventually have a tester? ...cos watching live data for engine speed, battery voltage and sensor readings during these tests would be relevant

Thanks for the input. I understand some power must be used to run the ac but what i am experiencing is a major drain on the engine power. This has not always been the case and i guess it has progressively been getting worse.

I do have a nanocon so i will run through the test described and see how it goes.
Cheers

Set nanocom on INSTRUMENTS mode and watch the sensor readings while you switch aircon on cos if it's an electrical issue and the current drain is too big the voltage will drop and it can affect sensor readings which would affect power too... also see how mucH the rpm and battery voltage drop is... if it passes this test it means it's some mechanical problem with the compressor clutch or pump which puts too much load on the drive belt... in this case my knowledge ends, i can only recommend to replace the compressor

I am experiencing a power loss when the AC is turned on and i am wondering what it could be that is wrong .

Most aircons get high pressure if the condenser fans are not working and this causes the compressor to drag power .
I understand/remember a post where the parameters are aircon on, ambient over 28C, under 80Kmh?
Check to see if your fan is working before anything else.
Regards Philip A

Originally Posted by sierrafery

HI, a certain power loss is normal, some things must be clarified:
1. how much is the initial rpm drop when you switch it on at idle?
2. do you experience the same power loss when you switch the aircon on regardless of outside temperature?
3. make a test, switch the aircon on then when you feel that power loss press ECON button and watch carefully...is there any change then? eventually play with ECON on/off to figure it out...also you can play with temp selection too, to see if there's any change when you select HI (when the compressor must rest) and LOW(when it must kick in)... to select HI/LOW hold both temp selection buttons up or down untill HI or LOW is displayed ... always wait few seconds after each selection to let the system settle ... do the tests at idle, listen to the engine and watch carefully the tachometer

any observed symptoms during these tests are important for the diagnose

do you eventually have a tester? ...cos watching live data for engine speed, battery voltage and sensor readings during these tests would be relevant

Most of the above will prove nothing. Playing with econ and temp buttons will just control how long the compressor runs. If it is off it will have no effect on power. If it is on it will, depending how much power loss, dictate whether or not there is a problem.

Compressor is either on or off, no in between. What can make a difference is the ambient temp. As it rises so does internal air con pressure causing compressor to work harder.

Originally Posted by d2dave

Most of the above will prove nothing. Playing with econ and temp buttons will just control how long the compressor runs. If it is off it will have no effect on power. If it is on it will, depending how much power loss, dictate whether or not there is a problem.

Compressor is either on or off, no in between. What can make a difference is the ambient temp. As it rises so does internal air con pressure causing compressor to work harder.

I know how the compressor works, these tests are to rule out an electric/electronic issue which can cause such power drain as to affect sensor readings and to rule out an aircon management issue which would activate the compressor without being necessary and then it will work harder than normally...the evaporator temperature sensor(thermistor) which is very important for compressor management is covered only for open or short circuit but it can missbehave and there's no other way to see that only by "playing" with aircon temp settings, ahd HI/LOW was a backup to compressor on or off in case the ECON doesnt work cos it can happen too...it's alsmost the same thing like what PhilipA well said if the fan doesnt work...though if it's very hot outside without the fan the pressure will build to the level where the dual pressure cuts the compressor out of if it fails the compressor's mechanical pressure relief valve will open

i'm not gonna explain the whole theory cos it's long but i've done these tests myself and they can be relevant... i found once a fault with that thermistor which caused such symptoms... believe me or not