Raji D
29-08-2008, 10:45 PM
Hi Guys
Would really appreciate some help on this noise im getting. Here are details. Iv tried to make it as detailed as possible
Car is a 97 civic sedan vti automatic CVT
bought 15 months ago at 117000km now at 133000km
noise is a not a rattle, not a continous whine but more a grindy squeely sound that has a frequency component to it that slightly sounds like a mettalic flap flapping against a rotating object
Sound is more in the mornings when its cold and is decreased (not much, only just noticably) in the arvos or when cars warmed up. Also in the morning th car feels like its dragging much more n needs to be pushed more to move th same, every so slightly though. Also in the mornings changing from park to reverse takes a second to a few seconds for th gears to change and if in this time i push th acclerator a bit th car slightly jerks and goes into gear, not so much a jerk as a quicker movement. As explained below, honda had reccomended a transmission flush at the servicing a few months ago. Not sure if this relates to the noise, the jolting or anything at all.
Sound happens in two situations
1) When accelerating STEADILY from stop with engine in range of 1.5-1.7 (as it is a CVT th revs dont change but car speed increases). The sound does not change ever in terms of its sound (frequency, nature or inensity at a given rpm), just louder sometimes sometimes not depending on how hard the car is being pushed (difference is slight). Most pronounced in that range. If accelerate heavily there is no sound, atleast not audible.
2) When you rev th engine up and let go off th accelerator, soon as you do so the sound comes as th engine drops revs for half a second or so and decreases in loudness exponentially. This occurs both if u rev th engine in neutral and let th revs drop off (while car is moving and stationary) or while u are driving with the revs in 2.5+ range (ie 100kmh+) and let go of th accelerator. When u are driving at lower speeds and let go it is not audible, so not sure if it is there.
As a side note, sometimes when th car is in neutral or park and i get out of the car i can hear what could be a slight, ever so slight similar noise, but much quiter.
It is hard to tell sometimes as the muffler drowns alot out. Its not after market, just stock with a hole in th pipe. But it sounds too nice to fix, not loud n annoying, but a nice deep hum :D
I degress, back to the noise
Importantly the sound of the noise does not change ever, the frequency or nature of the sound, only the intensity. It appears to come from the left of the engine bay somewhere infront of the battery but behind th belts - in that gap.
I'v taken the car to some service centres n they pretty much said we dont do transmissions take it to a transmission place. At a automatic transmission place th guy jus took it for a drive but i didnt really feel he got th full problem understood. He jus said its the transmission, sell it off while u can n buy something else. Not the best of help. I wasnt really convinced by this so I took it back to honda where a guy took it for a drive too and said its th tranny most likely but to take it to one of his mates who does only transmissions to have a look. This guy took it for a good drive, i drove it n showed him what i meant n we opened th hood and had a listen and then arrived at all the things iv outlined above.
Other possibly important notes, the engine has starting problems at low petrol levels <20% and if it gets too low will not start. Engine will crank but not start. A reccomended throttle body cleaning from honda adrressed this slightly and made th starting problems begin at a lower petrol level but still remains. Also honda at the last servicing (2 months or so ago) mentioned it needs a transmission flush (this fact is disputed by everyone who has seen it - and also by the honda tech that saw it today). Some of my friends have mentinoed that it feels like a manual in that when accelerating from stop it moves off, slightly decreases in pulling force and then pulls off normally again. This is at normal driving. Steady cruising off from start and spirited take offs this is not noticed. EVen so its fairly suttle. Not sure if this helps. I will add details to this as i can think of them
I'm no mech but my take is that because th sound is present in neutral also it cant be transmission (the second tranny guy agreed). I think there is something with the fuel supply, as when accelerating under a bit of strain, not too much, it is being forced to supply and then when revving it up and letting off quickly its recovering from alot of supply. This could explain why the frequencey of the sound doesnt change with road speed. Well that is an amatures pov
Help is greatly appreciated, I really dont want to have to either spend thousands on the tranny or sell it off at a great loss and then have to buy a new car.
thankyou in advance for taking th time to have a look at this
Would really appreciate some help on this noise im getting. Here are details. Iv tried to make it as detailed as possible
Car is a 97 civic sedan vti automatic CVT
bought 15 months ago at 117000km now at 133000km
noise is a not a rattle, not a continous whine but more a grindy squeely sound that has a frequency component to it that slightly sounds like a mettalic flap flapping against a rotating object
Sound is more in the mornings when its cold and is decreased (not much, only just noticably) in the arvos or when cars warmed up. Also in the morning th car feels like its dragging much more n needs to be pushed more to move th same, every so slightly though. Also in the mornings changing from park to reverse takes a second to a few seconds for th gears to change and if in this time i push th acclerator a bit th car slightly jerks and goes into gear, not so much a jerk as a quicker movement. As explained below, honda had reccomended a transmission flush at the servicing a few months ago. Not sure if this relates to the noise, the jolting or anything at all.
Sound happens in two situations
1) When accelerating STEADILY from stop with engine in range of 1.5-1.7 (as it is a CVT th revs dont change but car speed increases). The sound does not change ever in terms of its sound (frequency, nature or inensity at a given rpm), just louder sometimes sometimes not depending on how hard the car is being pushed (difference is slight). Most pronounced in that range. If accelerate heavily there is no sound, atleast not audible.
2) When you rev th engine up and let go off th accelerator, soon as you do so the sound comes as th engine drops revs for half a second or so and decreases in loudness exponentially. This occurs both if u rev th engine in neutral and let th revs drop off (while car is moving and stationary) or while u are driving with the revs in 2.5+ range (ie 100kmh+) and let go of th accelerator. When u are driving at lower speeds and let go it is not audible, so not sure if it is there.
As a side note, sometimes when th car is in neutral or park and i get out of the car i can hear what could be a slight, ever so slight similar noise, but much quiter.
It is hard to tell sometimes as the muffler drowns alot out. Its not after market, just stock with a hole in th pipe. But it sounds too nice to fix, not loud n annoying, but a nice deep hum :D
I degress, back to the noise
Importantly the sound of the noise does not change ever, the frequency or nature of the sound, only the intensity. It appears to come from the left of the engine bay somewhere infront of the battery but behind th belts - in that gap.
I'v taken the car to some service centres n they pretty much said we dont do transmissions take it to a transmission place. At a automatic transmission place th guy jus took it for a drive but i didnt really feel he got th full problem understood. He jus said its the transmission, sell it off while u can n buy something else. Not the best of help. I wasnt really convinced by this so I took it back to honda where a guy took it for a drive too and said its th tranny most likely but to take it to one of his mates who does only transmissions to have a look. This guy took it for a good drive, i drove it n showed him what i meant n we opened th hood and had a listen and then arrived at all the things iv outlined above.
Other possibly important notes, the engine has starting problems at low petrol levels <20% and if it gets too low will not start. Engine will crank but not start. A reccomended throttle body cleaning from honda adrressed this slightly and made th starting problems begin at a lower petrol level but still remains. Also honda at the last servicing (2 months or so ago) mentioned it needs a transmission flush (this fact is disputed by everyone who has seen it - and also by the honda tech that saw it today). Some of my friends have mentinoed that it feels like a manual in that when accelerating from stop it moves off, slightly decreases in pulling force and then pulls off normally again. This is at normal driving. Steady cruising off from start and spirited take offs this is not noticed. EVen so its fairly suttle. Not sure if this helps. I will add details to this as i can think of them
I'm no mech but my take is that because th sound is present in neutral also it cant be transmission (the second tranny guy agreed). I think there is something with the fuel supply, as when accelerating under a bit of strain, not too much, it is being forced to supply and then when revving it up and letting off quickly its recovering from alot of supply. This could explain why the frequencey of the sound doesnt change with road speed. Well that is an amatures pov
Help is greatly appreciated, I really dont want to have to either spend thousands on the tranny or sell it off at a great loss and then have to buy a new car.
thankyou in advance for taking th time to have a look at this