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  1. #1
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    Oct 2007
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    Low frequency flutter when idling!!

    Hi guys,

    I recently got my Altima Hybrid. I am in love with the looks and the EV mode performance. The only hassle or rather the irritation I have is when the gas mode kicks in when the car is idling even after the car engine has warmed up. You can hear a very distinct low frequency flutter from the gas engine probably because of the low rpms. The gas mode kicks in when the battery is almost empty. This happens when you run the AC while the car is idling for a long time in EV mode to discharge the battery.

    I had a toyota corolla before. This same problem (low rpms issue) appeared after like 15-20K miles on the car. A new car having this problem is putting questions in my head. If the rpms on a non-hybrid car are over 1000 rpms you dont hear it. But when it goes below 1000 rpms then you hear it.

    Does anyone have this problem in their NAH and is this in anyway going to affect the car in the long run?

    I took the car to the dealership and the tech gave me a reason that the sound was coming from the ac generator. I thought it was a bunch of garbage. I am an EE i know for sure that AC generators make a hum and not a flutter. The flutter I think is caused by the low rpms.

    Thanks

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  3. #2
    Junior Member
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    Aug 2007
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    Kamesh
    My NAH currently has 3900 miles on it (need to get the car in for its first service) and it does not appear to have this flutter sound that you have described.
    I had the car parked today and was sitting in it for about 15 minutes with the AC running. When the battery drained to about 1/3 level on the meter the ICE would start to recharge the battery. The only difference that I detected when the ICE started was that it seemed more noticeable than when it starts first thing in the morning or when leaving stoplights, etc. Now this could be due to the car was parked thus making the starting sequence more noticeable.
    I don't believe what you described was what I noticed. So far the only issues that my wife and I encounter when driving is the slight throttle searching that seems to happen when cruising on the freeway at around the 60 t0 65 range. At times when releasing the accelerator there is also a slight acceleration feeling but this may be nothing as my Ford F150 does something similar.
    On two different occasions, my wife observed the battery meter at zero then quickly recovering. Not sure of the circumstances as to when this happened.
    Still enjoy the car and hope this feeling lasts.
    dierk

  4. #3
    Junior Member
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    Oct 2007
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    All is well that ends well!!

    Dierk:

    Thanks for your response. Just to clear my head out, I went and test drove 2 other brand new hybrid cars which had less than 12 miles on them and they had a similar flutter too. So I think its to do with the hybrid engine design in conjuction with the nissan's CVT. So I guess I have to say I am being paranoid about nothing. . Good for all the other hybrid owners. Anyway... Have fun with your NAH. Hopefully I will have a good time too... I will be making my first long trip this weekend. Thanks again.

    kamesh

  5. #4
    Junior Member
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    Oct 2007
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    Low Frequency Flutter !!

    OK. Guys... After further research with regards to the irritating noise... I have come across people who have faced similar problems. The reason for this flutter or rattle as people call it (during start-up till the ICE gets warmed up) is to do with heat shield bolts. It seems like Nissan is aware of this problem and have done nothing about it yet. In the meantime... the car mechanics are trying to fix it by using a different type of washer before the bolt to hold down the Heat Shields on the exhaust. This problem is common to most 2007 Nissan Cars. Many people who have owned corolla's came up with the same problem after 15-20K miles as these Bolts tend to loosen a little over time due to wear and tear. But most times it only appears at startups as they are initially loose when cold. As the engine warms up and the bolts get heated they expand and hence the noise doesnt appear anymore. But in case of Hybrids... this tends to be more regular.. as people try to utilize the EV mode more to increase MPGs and in the process cooling down the ICE.

    So Be aware of this issue and let your car mechanic know about this. I am taking my car to get this fixed this coming Monday and will let you guys know how it worked out. Also be aware that most 2007 Altima's also have a slight play on they brakes. That is there is a free movement on the brake pedal may be for a half inch or so and then the brakes actually set in.

    Please let me know if any of you guys are facing the same problems.

    Thanks

  6. #5
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    Nov 2006
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    thanks for following up on this....that's interesting!

  7. #6
    Junior Member
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    Dec 2007
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    Quote Originally Posted by KAMESH View Post

    So Be aware of this issue and let your car mechanic know about this. I am taking my car to get this fixed this coming Monday and will let you guys know how it worked out. Also be aware that most 2007 Altima's also have a slight play on they brakes. That is there is a free movement on the brake pedal may be for a half inch or so and then the brakes actually set in.

    Please let me know if any of you guys are facing the same problems.

    Thanks
    I noticed the play in the brake pedal today for the first time (I've only got about 415 miles on my car). Thought I was crazy for a minute, but now I know I'm not

    Sarah-

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