Possible small vacuum leak

[rjkoop]

My '81 starts, idles and runs fine finally so not sure why I'm complaining but... One minor thing I noticed is that when I rev up the engine I notice a minor vacuum sucking noise. Here's a video (audio quality not great but hopefully you can hear the sucking noise when I rev up the engine each time).

https://youtu.be/sJbOJ8Mo_KU

Is there an easy way of pinpointing this? I'll ensure that all the vacuum links are tight 1st I guess.

[4uall]

May just be the angle however, the hose going to the top of the charcoal canister looks tight and stretched

[narfire]

Sounds like it is idling OK around 8-900rpm? brakes ok? wondering if the brake booster diaphragm might have a tear/hole.

[rjkoop]

May just be the angle however, the hose going to the top of the charcoal canister looks tight and stretched

Yep, the charcoal canister hose is stretched but connected correctly. I'll double check though. The cap for the canister has a broken tab. So it's kind of just sitting on top. Should get a new one. Would a missing/loose cap on the canister cause a minor vacuum leak? If so, then this is probably it.

[rjkoop]

Sounds like it is idling OK around 8-900rpm? brakes ok? wondering if the brake booster diaphragm might have a tear/hole.

Idle is good but may need a bit of adjustment. It sounded like the sucking noise was coming from around the canister area (near the front driver's side). So don't think it's the brake booster.

[4uall]

like you said, i would double check all the connections. i just found out (ironically) that one of my silicone hoses had a small crack in it at the connection point last night

[rjkoop]

Turned out that vacuum leak was caused by the hose from the brake booster to the intake manifold not being very tight. Once I tightened it the vacuum sound went away. Another issue resolved...