Can someone help me identify this sound?
02-24-2019, 06:46 AM
#1
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Thread Starter
Can someone help me identify this sound?
So, now that I've nearly resurrected my 944 it's time to check some other issues I knew it had. One of them is a tocking sound that occurs when I let off the throttle. I can feel the vibrations of this sound when I put my hand on the throttle body.
Here is a clip of the sound, note the rapid tocking sound as soon as I let off the throttle:
Somehow the sound is much more noticeable on the recording than it is normally. Normally it sounds like it's coming from deep inside the engine (which is the main concern for me.)
I don't plan on driving this thing before I exactly know what causes this.
I thought it may be the airflow door in the AFM, but would that make sense?
Here is a clip of the sound, note the rapid tocking sound as soon as I let off the throttle:
Somehow the sound is much more noticeable on the recording than it is normally. Normally it sounds like it's coming from deep inside the engine (which is the main concern for me.)
I don't plan on driving this thing before I exactly know what causes this.
I thought it may be the airflow door in the AFM, but would that make sense?
02-25-2019, 09:08 AM
#2
Pro
Doesn’t sound like an AFM door to me. Before I switched over to a MAF setup, I would hear a slight metal-on-metal “clank” when I would let off the throttle as you demonstrate. Turned out to be my AFM door “slamming” shut.
Not much help, as I can’t tell you what it sounds like. Just thought I’d chime in with what it doesn’t sound like.
Good luck in tracking it down! Curious to hear what you find. Mechanics stethoscope might come in handy.
If I had to describe it, it sounds “hollow” and non-metallic, at least in the video. Any chance there’s a real loose balance shaft belt making contact with the belt cover up front?
Not much help, as I can’t tell you what it sounds like. Just thought I’d chime in with what it doesn’t sound like.
Good luck in tracking it down! Curious to hear what you find. Mechanics stethoscope might come in handy.
If I had to describe it, it sounds “hollow” and non-metallic, at least in the video. Any chance there’s a real loose balance shaft belt making contact with the belt cover up front?
02-26-2019, 11:01 AM
#4
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Thread Starter
I've removed the belt cover this afternoon and the belts seem fine. If they had hit the cover continuously it should've shown on the belts. Balance belt is kind of loose on a cold engine, there is about 1 cm give or take movement up and down but if I recall correctly, it wasn't supposed to be super tight was it?
Ran the engine with the cover off and nothing out of the ordinary to be seen. I did notice that the sound comes once the engine has been warmed up.
I think I am gonna take a short sabbatical from this car because the longer I listen, the more sounds I hear. I'm probably just a little paranoid after spending "a small sum" of money on fixing this thing.
Ran the engine with the cover off and nothing out of the ordinary to be seen. I did notice that the sound comes once the engine has been warmed up.
I think I am gonna take a short sabbatical from this car because the longer I listen, the more sounds I hear. I'm probably just a little paranoid after spending "a small sum" of money on fixing this thing.