Car intermittently shakes at idle only when A/C is on
#1
Car intermittently shakes at idle only when A/C is on
Hi there, I tried searching for this on the forums but didn't see anyone else posting about it.
My 2005 6spd RX-8 (about 128k miles) will shake periodically when idling and when the a/c is turned on. It's the kind of shaking you get when the car idles at a really low RPM. It shakes for about 5 seconds, then it stops shaking, then it'll start shaking again about 45 seconds later or so. When my a/c is turned off, the car doesn't experience any shaking when idling -- it's just normal idling. Turn the a/c on again and the intermittent shaking resumes. I dont know if the RPMs are being affected or not; I dont know if the RPMs are dropping at the exact moment the car starts shaking or if they're increasing or going back to normal when the shaking stops. I can't recall and my fiancee has the car right now so I can't check.
Any ideas? Is there anything I should check for? Thanks for your help!
My 2005 6spd RX-8 (about 128k miles) will shake periodically when idling and when the a/c is turned on. It's the kind of shaking you get when the car idles at a really low RPM. It shakes for about 5 seconds, then it stops shaking, then it'll start shaking again about 45 seconds later or so. When my a/c is turned off, the car doesn't experience any shaking when idling -- it's just normal idling. Turn the a/c on again and the intermittent shaking resumes. I dont know if the RPMs are being affected or not; I dont know if the RPMs are dropping at the exact moment the car starts shaking or if they're increasing or going back to normal when the shaking stops. I can't recall and my fiancee has the car right now so I can't check.
Any ideas? Is there anything I should check for? Thanks for your help!
#2
USMC
iTrader: (3)
This is fairly common with all cars. Using a/c puts more load on the engine and at idle it may cause the RPMs to drop down until more fuel is injected to re-stabilize the idle. I wouldn't worry too much about it, unless it is causing excessive problems. This is an electrical-related problem so you could try cleaning up the grounds, battery terminals, etc. Another member might be able to chime in and give you a better solution.
#3
Charles Bundy
iTrader: (5)
Are you in your original engine? If I can recall, I started to experinced that shaking when I was close to 150,000 miles on mine. I did as suggested above and also replaced my whole ignition system which helped. What I would worry more on is if your engine couldn't handle the load and turning the A/C would eventually cause your car to stall.
#7
This is fairly common with all cars. Using a/c puts more load on the engine and at idle it may cause the RPMs to drop down until more fuel is injected to re-stabilize the idle. I wouldn't worry too much about it, unless it is causing excessive problems. This is an electrical-related problem so you could try cleaning up the grounds, battery terminals, etc. Another member might be able to chime in and give you a better solution.
I believe the previous owner replaced the coils, spark plugs, and wires about 3k miles ago.
I take it most of you experience this shaking too when idling with your air conditioning on? The whole car shakes when it does it and it produces a really low-pitched rumbling sound.
What should I check for when inspecting the motor mounts? What will they look like if they're damaged vs if they're fine?
#8
weeeeeeeeee
iTrader: (12)
I had this problem, sorta, plus some of my IC piping rattling against the subframe from time to time at low RPMs - 700+/-
I've since increased my idle to 950 RPM and no longer worry of either.
Your motor mounts should be solid and well formed. It's fairly easy to inspect them from under the car.
I've since increased my idle to 950 RPM and no longer worry of either.
Your motor mounts should be solid and well formed. It's fairly easy to inspect them from under the car.
#9
Charles Bundy
iTrader: (5)
There is a TSB for checking that. If I can remember, drive the car then while you are decelerating in third gear at less than 3,000 RPM and about 30mph, quickly floor the accelerator pedal; if you feel a shake and very noticeable hesitation occurs, it may indicate that your engine mount(s) is/are worn.
#11
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Drop the Air conditioner
New to this rx8 site. I have a question. Can I omit the A/C from the power train by simply removing the belt?. Will I draw a cel?. I never use the A/C and I figure it might give me a little more get up and go.
I have owned it for 4 years now. It's a 2004 series one 4 speed automatic. Just runs superb but thought I could get more power by droping the A/C I don't use any way?. Any one ever done this.?.
I have owned it for 4 years now. It's a 2004 series one 4 speed automatic. Just runs superb but thought I could get more power by droping the A/C I don't use any way?. Any one ever done this.?.
#13
Registered
New to this rx8 site. I have a question. Can I omit the A/C from the power train by simply removing the belt?. Will I draw a cel?. I never use the A/C and I figure it might give me a little more get up and go.
I have owned it for 4 years now. It's a 2004 series one 4 speed automatic. Just runs superb but thought I could get more power by droping the A/C I don't use any way?. Any one ever done this.?.
I have owned it for 4 years now. It's a 2004 series one 4 speed automatic. Just runs superb but thought I could get more power by droping the A/C I don't use any way?. Any one ever done this.?.
#14
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@peteInLongBeach: Thx, it was just a thought. Always looking for more what I call Driveability which isn't always more horse power. I just made my own ran air set up and took it on the freeway to test ad was a notice able response. Also interested in serpentine belting of the rx8, maybe some lighter pullys for unsprung torq. Having fun:
A woman walked up to me last Sunday after skating was over and said "Is this your second child hood" referring to my 8. I responded: NO this is still my first". He he he.
A woman walked up to me last Sunday after skating was over and said "Is this your second child hood" referring to my 8. I responded: NO this is still my first". He he he.
#15
I have this promblem when the heater is on or the a/c it happens when either the compressor kicks on then off or the fan kicks on or off just alittle vibration. Then it goes away then comeback on
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