Strange sucking noise from engine

[Guest]

Started engine this morning, left the bonnet open and let it tickover, no problem.

Revved it a couple of times and noticed a very distinct sucking noise, not the usual induction sound. If you mouth the word 'O' and suck in sharply, that is what I hear. Then let off the gas and the sharp sucking noise slowly goes as if it's actually breathing. Revs then drop right off, and it continues to idle lumpy the slowly returns to steady idle. It also cut out once.

If I rev it more slowly up the rev counter I don't hear the noise at all..

Any ideas?

 

[Guest]

hi i have/had quite similar thing in my car only i couldn't allways here the sucking noise but about revving and idle just the same as you
sry for the "hijack"

//excudo

 

[Guest]

You may have a vacuum leak somewhere. Check all hosing around the inlet. Also make sure inlet manifold/throttle body are mated up properly. Unmetered air will cause lumpy running and in some cases backfiring, but usually lumpy idle and vacuum noises are a clear indicator something simple like a hose or gasket aren't right. Easy fix either way. Just need to get your head in there and listen to pin point it fella.

 

[Guest]

Great thanks, ill recruit my girlfriend to blip the throttle whilst i do some troubleshooting. She's going to hate me, they just don't understand :lol:

 

[Guest]

just move the throttle in the engine bay?

 

[Francis [Bot]]

Could be to do with your your idle control valve? Mine made that sort of noise when it was fucked - admitadely it did make the car idle at about 4500rpm though :lol:.

 

[Guest]

spray carb cleaner about on vac pipes, tb gasket etc, if there is a leak the revs will change due to mixing with carb cleaner