Alzg22
06-18-2010, 05:33 PM
(2003 Civic SI EP3)
A few weeks back I started to notice a loud sound coming from the engine bay. The only clear way to describe it is like a circular saw cutting through wood. The weird thing about this noise is it only occurs at certain RPM's, around 1500, and most clearly 2200-2400 - I've also heard it at higher RPM's such as over 4000 but you can't really hear it too clearly over the engine noise at that point.
You can hear it while the engine is accelerating or decelerating. The car will make the sound regardless whether it's moving or stopped, it'll make it in all gears including neutral or if the clutch is depressed - which pretty much leads me to believe that this is definitely an engine issue. For instance, I'm in 2nd gear and I rev the engine up from 2000 to 2500 RPM, you can hear the sound clearly in the middle of that RPM band while accelerating; then when I clutch to shift up to 3rd and the RPM's drop back down, you can hear the noise while the RPM's drop past that 2200-2400 threshold. What concerns me the most is how you can only clearly hear it at certain RPM's.
The only modification on my car is an AEM short-ram intake. I installed it when I got the car - and even though it makes a quiet whistling sound when lightly accelerating which is normal, this new saw-like noise has just started occurring. My gut tells me it could be the heatshield, but my bro-in-law said it could be the timing chain tensioner (which I'd imagine would sound more like a rattle than a circular saw cutting through wood).
Any help would be greatly appreciated.
-Al
A few weeks back I started to notice a loud sound coming from the engine bay. The only clear way to describe it is like a circular saw cutting through wood. The weird thing about this noise is it only occurs at certain RPM's, around 1500, and most clearly 2200-2400 - I've also heard it at higher RPM's such as over 4000 but you can't really hear it too clearly over the engine noise at that point.
You can hear it while the engine is accelerating or decelerating. The car will make the sound regardless whether it's moving or stopped, it'll make it in all gears including neutral or if the clutch is depressed - which pretty much leads me to believe that this is definitely an engine issue. For instance, I'm in 2nd gear and I rev the engine up from 2000 to 2500 RPM, you can hear the sound clearly in the middle of that RPM band while accelerating; then when I clutch to shift up to 3rd and the RPM's drop back down, you can hear the noise while the RPM's drop past that 2200-2400 threshold. What concerns me the most is how you can only clearly hear it at certain RPM's.
The only modification on my car is an AEM short-ram intake. I installed it when I got the car - and even though it makes a quiet whistling sound when lightly accelerating which is normal, this new saw-like noise has just started occurring. My gut tells me it could be the heatshield, but my bro-in-law said it could be the timing chain tensioner (which I'd imagine would sound more like a rattle than a circular saw cutting through wood).
Any help would be greatly appreciated.
-Al