Chimaera whistle on acceleration
Discussion
Hi, I have a '98 Chim 500. Drives great but there's a problem that's got me puzzled.
When accelerating hard at about 3000-4000 rpm I'm hearing quite a loud whistle. If I ease off the gas a bit it disappears. Seems to come from the front of the car, engine bay.
Sounding like it might be an inlet leak, my garage smoked the air intake to look for leaks. Nothing from the plenum, inlet manifold or beyond and just a small issue around both sides of the throttle butterfly shaft where it sits in the throttle body. We don't think that's likely to cause the whistle.
I can't recreate the sound in the garage by revving, only on the road under fairly hard acceleration.
Maybe someone else had had the same problem and knows what's causing it?
Grateful to know.
Cheers
When accelerating hard at about 3000-4000 rpm I'm hearing quite a loud whistle. If I ease off the gas a bit it disappears. Seems to come from the front of the car, engine bay.
Sounding like it might be an inlet leak, my garage smoked the air intake to look for leaks. Nothing from the plenum, inlet manifold or beyond and just a small issue around both sides of the throttle butterfly shaft where it sits in the throttle body. We don't think that's likely to cause the whistle.
I can't recreate the sound in the garage by revving, only on the road under fairly hard acceleration.
Maybe someone else had had the same problem and knows what's causing it?
Grateful to know.
Cheers
Has it just developed the noise for no apparent reason or has it always been there.
I have had such a noise on my car. On mine it was because i had taken the throttle heater plate off from the underside of the plenum. Cant remember now but one or two of the bolts that hold it in place go straight through into the plenum so they have to be replaced to avoid an air leak. I cut these bolts down too far and so the ends of them were not flush with the inside of the plenum. Result was as the air went over it, it whistled only under acceleration. Solution was to replace the said bolts so they were the correct length to be flush with the inside of the plenum.
Check and see If your throttle heater plate is present or not.
I have had such a noise on my car. On mine it was because i had taken the throttle heater plate off from the underside of the plenum. Cant remember now but one or two of the bolts that hold it in place go straight through into the plenum so they have to be replaced to avoid an air leak. I cut these bolts down too far and so the ends of them were not flush with the inside of the plenum. Result was as the air went over it, it whistled only under acceleration. Solution was to replace the said bolts so they were the correct length to be flush with the inside of the plenum.
Check and see If your throttle heater plate is present or not.
carsy said:
Has it just developed the noise for no apparent reason or has it always been there.
I have had such a noise on my car. On mine it was because i had taken the throttle heater plate off from the underside of the plenum. Cant remember now but one or two of the bolts that hold it in place go straight through into the plenum so they have to be replaced to avoid an air leak. I cut these bolts down too far and so the ends of them were not flush with the inside of the plenum. Result was as the air went over it, it whistled only under acceleration. Solution was to replace the said bolts so they were the correct length to be flush with the inside of the plenum.
Check and see If your throttle heater plate is present or not.
Carsy, thanks. Interesting. I've only owned the car for 5 months so I don't know if the heater plate has been removed. I'll need to look. Is it inside the plenum? What's the benefit of removing it? Cheers. I have had such a noise on my car. On mine it was because i had taken the throttle heater plate off from the underside of the plenum. Cant remember now but one or two of the bolts that hold it in place go straight through into the plenum so they have to be replaced to avoid an air leak. I cut these bolts down too far and so the ends of them were not flush with the inside of the plenum. Result was as the air went over it, it whistled only under acceleration. Solution was to replace the said bolts so they were the correct length to be flush with the inside of the plenum.
Check and see If your throttle heater plate is present or not.
Sorry not very good at posting pics etc but look at this thread, there are pictures of it. The thread probably covers everything you would want to know about it.
I dont think there is any real advantage to removing it other than for ocd neatness. Its not used on a TVR so i didnt see the point in having it with 2 rusty pipes sticking out on show.
http://www.pistonheads.com/gassing/topic.asp?h=21&...
I dont think there is any real advantage to removing it other than for ocd neatness. Its not used on a TVR so i didnt see the point in having it with 2 rusty pipes sticking out on show.
http://www.pistonheads.com/gassing/topic.asp?h=21&...
carsy said:
Sorry not very good at posting pics etc but look at this thread, there are pictures of it. The thread probably covers everything you would want to know about it.
I dont think there is any real advantage to removing it other than for ocd neatness. Its not used on a TVR so i didnt see the point in having it with 2 rusty pipes sticking out on show.
http://www.pistonheads.com/gassing/topic.asp?h=21&...
Thanks Carsy. The plate on mine is all in place with no pipes attached so sounds like original fitting. I dont think there is any real advantage to removing it other than for ocd neatness. Its not used on a TVR so i didnt see the point in having it with 2 rusty pipes sticking out on show.
http://www.pistonheads.com/gassing/topic.asp?h=21&...
which was causing the whistle.
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