Bad vibration at idle when AC compressor kicks in

I have a 97 accord EX. When sitting in the car with the engine idling,
the whole car starts to shake and vibrate when the AC compressor kicks
in. The engine normally idles at about 7500rpm. When the AC compressor
kicks on, the RPM drops which causes the shaking. Is it simple to have
a mechanic raise the idle speed of the engine a bit? Anyone else
experience this problem with 94-97 accords? Thanks

That happened to me once (actually to someone whose car I was looking at for
the same problem). The AC compressor was seizing up, the belt caught on
fire shortly thereafter, lots of smoke...

Probably there's a similar reason why your car is telling you it needs help,
quickly...but maybe not. 750 rpm, not 7500 I presume...

Brian


> wrote in message
oups.com...
>I have a 97 accord EX. When sitting in the car with the engine idling,
> the whole car starts to shake and vibrate when the AC compressor kicks
> in. The engine normally idles at about 7500rpm. When the AC compressor
> kicks on, the RPM drops which causes the shaking. Is it simple to have
> a mechanic raise the idle speed of the engine a bit? Anyone else
> experience this problem with 94-97 accords? Thanks
>

There is a mechanism to kick the idle when the compressor load comes
on. The idle should stay about constant. However, Brian may be right
that your compressor may be binding. You need to loosen the compressor
belt and rotate the compressor manually to check for excessive
friction/binding.

Professor
www.telstar-electronics.com

Professor wrote:
>
> There is a mechanism to kick the idle when the compressor load comes
> on. The idle should stay about constant. However, Brian may be right
> that your compressor may be binding. You need to loosen the compressor
> belt and rotate the compressor manually to check for excessive
> friction/binding.

Turning the compressor by hand might not tell you anything. If the
clutch doesn't engage when the engine isn't running, the pulley will
turn free even if the compressor is seizing.

I'd have the shop check out the idle control. Engines shake when they
are lugged below their normal idle speed, which sounds like the symptom
described.

--
Paul Hovnanian
------------------------------------------------------------------
Any sufficiently advanced technology is indistinguishable from a rigged
demo.

wrote:
> I have a 97 accord EX. When sitting in the car with the engine idling,
> the whole car starts to shake and vibrate when the AC compressor kicks
> in. The engine normally idles at about 7500rpm. When the AC compressor
> kicks on, the RPM drops which causes the shaking. Is it simple to have
> a mechanic raise the idle speed of the engine a bit? Anyone else
> experience this problem with 94-97 accords? Thanks
>

how new are the plugs, wires/rotor/distributor cap? new plugs may help
the rough idle. you shouldnt have to actually touch the idle speed
setting, doing so just masks the symptoms.

On 2005-06-06 said:
>Newsgroups: rec.autos.tech,rec.autos.makers.honda,rec.autos.mi sc
>There is a mechanism to kick the idle when the compressor load comes
>on. The idle should stay about constant. However, Brian may be right
>that your compressor may be binding. You need to loosen the
>compressor belt and rotate the compressor manually to check for
>excessive friction/binding.
>Professor
>www.telstar-electronics.com
And remember to turn the AC on or you will only be testing the clutch
for binding. (Better remove the belt for this test.)


Tom Willmon
near Mountainair, (mid) New Mexico, USA

Did you ever stop to think, and then forget to restart?

Net-Tamer V 1.12.0 - Registered

What I had in mind was turning the compressor... not just the pulley. I
would get a socket that fit the nut on the pulley and turn the
compressor shaft to detect any binding.

Professor
www.telstar-electronics.com