1986 3.2 Carrera, engine whistling / hissing sound when throttle applied

[darrin]

@thisisgoodnews -- did you replace the idle speed adjustment screw o-ring and/or investigate that as a source of noise?

[thisisgoodnews]

Originally Posted by darrin

@thisisgoodnews -- did you replace the idle speed adjustment screw o-ring and/or investigate that as a source of noise?

Yes, I did right after you posted - placing my finger over the adjustment screw caused no difference.

[pmax]

Originally Posted by thisisgoodnews

Tried to do a quick search but with very little luck - so apparently a hissing / whistling sound developed when throttle is applied, occurs at low, around ~2k rpm. In the video, engine is at running temp, idle is stable, everything else is seemingly normal - no other strange sounds.



Any hints where should I look first would be appreciated.

Some "knocking" sounds at 0.07 and 0.17 or thereabouts ... hear them ?

Originally Posted by thisisgoodnews

Anyhow, first think, I put back the stock cover, the sound was still there, but much less audible, and almost inaudible from the inside of the car, when driving. I am sure, If I also put the stock air filter in, the sound would be totally gone. I also serviced the air filter, washing and spraying it with oil, and the note of the sound slightly changed. So my theory is, as I didn't oil the filter when taking it out the box when installing it (it was oiled from the factory), the oil might have dried out in some time, and the sound became more and more obvious. So this case is closed.

Perhaps, the filter loosened up after a while and the reinstallation fixed that. The OEM clips hold the lid down tight, compressing the air filter frame evenly all around in the process.

[thisisgoodnews]

Originally Posted by pmax

Some "knocking" sounds at 0.07 and 0.17 or thereabouts ... hear them ?

Can hear it at lest on 0:07, these are coming from the exhaust, how are they called, pops'n'bangs? Car has Fabspeed cat-bypass and muffled, so they happen from time to time, when depressing throttle.

Originally Posted by pmax

Perhaps, the filter loosened up after a while and the reinstallation fixed that. The OEM clips hold the lid down tight, compressing the air filter frame evenly all around in the process.

Could be. But overall, the Fabspeed air box cover frame is very sturdy, I am sure it also holds the air filter tight in spot.

[Cherry Bomb]

Glad it got sorted! Time to bathe & oil my filter as well.

Happy Motoring