a/c pulsing and rough idle

[98vtec5spd]

ok so today while i was driving with the a/c on while idling the a/c would cause the engine to idle roughly. and while driving i could hear the a/c pulsing. im not sure what could cause this. as usual i am open to any suggestions.

thanks in advance

David

 

[Gil'sCG6]

lemme guess 4 cylinder huh?

 

[98vtec5spd]

yep that is correct. its odd b/c this has never happened before

 

[HondaLuver83]

Idle drop is normal bevause there is extra drag on the motor. As far as the pulsing i have no idea. Check ur ac pressure if its going on and off fast

 

[Gil'sCG6]

the drop of idle and noticeable loss of power is normal but also more noticeable on the 4 cylinders seeing as they dont have as much power as the 6 cylinders to counter act the drag from the belt driven a/c system. So in a nutshell you have to give a little to get a little when it comes to a/c on the 4 cylinders. Now the pulsing is something that you'd have to take to an experienced mechanic so they can see the characteristics and diagnose the problem for you, it could be something as small as the a/c belt or something bigger like the compressor who knows.

 

[knighthawk1104]

probably the compressor. it could be something totally different as in, the ac is fine but something else in the car is messed up causing the car to run a little weird and when you turn the ac on and put more drag it might cause the rough idle. just a thought.

 

[jcollins6]

does it sound like the compressor is "cycling"? Meaning that the clutch kicks on and off? if it is then you are low on freon and need to have it looked at for leaks.

 

[kwak123]

the engine does idle more roughly with the 4 cylinder... i would knwo my i4 has been essentially rebuilt and still idles rather roughly when the a/c is on, but only at intervals... the pulsing, do you mean you hear a pulsing noise from the hood?

 

[98vtec5spd]

the engine does idle more roughly with the 4 cylinder... i would knwo my i4 has been essentially rebuilt and still idles rather roughly when the a/c is on, but only at intervals... the pulsing, do you mean you hear a pulsing noise from the hood?

ok so with the pulsing i can hear it from inside the car with the radio on. with the rough idle that i am refering to is when the can sits in neutral and has the normal 700rpm idle when the a/c is on the idle will drop down to between 150 - 200 rpm idle

 

[kwak123]

check your oil, crank case sensors, check IAC,