Pffft sound and momentary interuption in acceleration when running air conditioner

BRIANTHECURIOUS

MEMBER
1998 HONDA CRV
2.0L
4 CYL
AWD
MANUAL
259,000 MILES

My vehicle operates normally when I am not using the air conditioner; however, when I turn on the AC I will occasionally hear a *Pfffft sound and experience a momentary loss in acceleration. It feels like a timing/valve issue, but I cannot understand why it would only occur when I use the AC. Of course, I am new to the world of auto mechanic stuff so I really do not know what I am talking about. Can someone educate me? :-)

Wednesday, April 13th, 2016 AT 1:00 PM

4 Replies

CJ MEDEVAC

MECHANIC
11,005 POSTS

THIS SOUNDS LIKE THE AIR CONDITIONER CLUTCH ENGAGING

THIS MEANS THAT THE AIR CONDITIONER COMPRESSOR (WHICH IS NOT TURNING AT ALL) SUDDENLY "HOOKS UP WITH" THE FAST TURNING AIR CONDITIONER CLUTCH PULLEY WHEN IT IS CALLED ON TO DO SO.

USUALLY THERE IS NO NOTICEABLE DRAG DOWN IN ENGINE POWER, ESPECIALLY ON BIGGER ENGINES (THOUGH YOU STILL HEAR THE NOISE!)

IF IT REALLY SEEMS EXCESSIVE (IF YOU'RE LIKE ME, YOU ARE REALLY "TUNED INTO" THIS OCCURRENCE), HAVE AN AUTOMOTIVE AIR CONDITIONER PROFESSIONAL CHECK ITS OPERATION.

ALSO CONSIDER THE SMALL ENGINE SIZE, THE LOADS YOU ARE MOVING, TERRAIN AND THE LAST TUNE-UP.

MOST VEHICLES NOW-A-DAYS USE "A/C COMPRESSOR (EVAPORATOR)" TO REMOVE MOISTURE FROM THE AIR IN ANY HEAT SETTING THAT USES "DEFROST". MORAL OF THE STORY: THE A/C CLUTCH MAY BE HEARD ENGAGING WHILE IN A DEFROST MODE

THE MEDIC

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Wednesday, April 13th, 2016 AT 6:59 PM

BRIANTHECURIOUS

MEMBER
2 POSTS

Thank you for your response, CJ Medevac!

This makes sense about the air conditioner compressor/clutch engagement. I should also clarify that it does not just occur when I flip on the air conditioner. It continues to occur periodically while I am driving and seems to continue for up to the first twenty to thirty minutes that I have the air conditioner turned on. The *pffft sound and engine disruption seem the most pronounced under harder acceleration or when I am about to shift gears. Does that alter your diagnosis in any way?

Again thank you for your response. I appreciate it!

Brian

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Thursday, April 14th, 2016 AT 11:01 AM

KEN L

MASTER CERTIFIED MECHANIC
51,598 POSTS

Happy to help use 2Carpros anytime!

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Sunday, April 17th, 2016 AT 6:57 PM

CJ MEDEVAC

MECHANIC
11,005 POSTS

JUST SAW YOU

SOMEHOW MISSED THE NOTIFICATION/ CLICKED ON IT/ OVERLOOKED IT

WHEN YOU TURN ON THE A/C OR DEFROST

THE SYSTEM "TURNS ON"

THE COMPRESSOR ENGAGES UNTIL IT "GETS SATISFIED", THEN IT STOPS COMPRESSIN' OR RATHER THE CLUTCH TURNS OFF

WHEN IT SENSES THE NEED TO COME BACK ON, IT DOES!

DEPENDING ON THE "CHARGE" IN THE SYSTEM IT MAY ENGAGE MORE OR LESS OFTEN

ALL OF THIS HAPPENING WITH THE SYSTEM TURNED "ON"

MY A/C IS KINDA SORTA AMBIENT AIR TEMP DEPENDENT, SEE MY PIC BELOW

THE MEDIC

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