Whistling sound from induction

[djs]

1975 2.0, stock D-Jetronic injection.

Here's an esoteric nuisance issue that perhaps someone else has dealt with.

I have had an annoying whistling sound coming from my intake runner on one side. It seems to come from just one runner, about where the runner joins the metal distribution box.

On the theory that I had an air leak somewhere, I swapped the air box for another one I had on hand and I also installed brand new intake runner boots, complete with clamps. Now the whistling noise seems reduced, but it's still there. It's definitely related to high vaccuum, and is only apparent when idling. It might have something to do with the steel runners themselves vibrating at a really high frequency, but it sounds and acts like a whistling condition.

Anyone else have this problem?

Thanks in advance!

Dan

[Kevin@ojai.net]

My experience with sounds like that is that it is a vaccum leak. To verify this you could spry some carb cleaner (be carefull though) where the whistle is coming from, if it changes the idle at all, it is a vacuum leak, and you should fix it ASAP!

-Kevin

[Roland Kunz]

Hello

Check if your throttle body bypass screw generates the sound or if it changes if you turn it slightly.


Also possible sticking cold start bypass valve. Just compress the hose to it.

Grüsse