Ecotec Vaccum leak

[HamaTime™]

Ok well for the past 3 - 4 weeks my cursed vaccum leak has come back to haunt me. It appears that all my 2010 car maintenance/headaches has come in the space of 5-6 weeks.

I have had a vaccum leak before which occurred after a couple of LPG backfires which blew the airbox, the MAF and the Throttle Body end off the Vaccum purge line (connects at the back of the manifold), fixed all 3 of them and now she's sweet.

Now it's happened again, from what I recall I haven't had any backfires....it has stalled a couple of times on start up, and with gas that creates a big POP....thanks to some start up mixtures been thrown off, but thats fixed. My thoughts have been.

• Leaking airbox/CAI - (siliconed up the joins in the airbox - CAI and refit everything tightly
• Fiddled with the Vaccum Purge line - It's super glued in, I have a spare one which I could somehow join together and refit so there is a complete flush fit...(WHY ARE THEY SO SHORT STOCK!)
• Blown MAF
• Air Leak somewhere else in the motor

When I plant the foot it's so laggy (even more so) and it hisses, there is an induction noise but I swear this one is different.

My Mechanic has looked twice and said it's just an induction noise. But I still think that there is air escaping somewhere.

Anyone have any suggestions?

I could strip the Intake/Manifold completely and turf it, go to Nick a Part and get a new one, replace the Manifold Gasket etc etc. Then at the same time fit my 1.98.1 Rockers, 25 mm Insulator and 12 mm Plenum Spacer (MACE mods start!)...

[delcowizzid]

what makes you think it has a vacuam leak

[nathanVY]

I swear mine still has a vac leak. when i first got it the vent selectors didn't work - turned out the vac tank had a MASSIVE hole in it so after replacing the tank and some hoses and the vac solenoid block the vents worked again. still as sluggish as a truck.

[HamaTime™]

what makes you think it has a vacuam leak

Well whilst accelerating it has a very distinct hissing noise. Same noise as before when I found that the Vaccum purge line had been blown off. But that isn't really an issue any more since I've superglued the ends on (removal via the rubber elbows).

So that's why I thought it could be a vaccum leak. could be escaping air from somewhere though. Or it could just be an induction noise and the lack of power is from another blown MAF?

Who knows! There's so many things it could be...which is why i'm drawing wider knowledge from the JC community.

[delcowizzid]

could be the IAC opening they hiss like a mofo i can hear mine even after its gone through heaps of 3" pipe and through an intercooler and out the turbo

[VK SL 3800]

Well whilst accelerating it has a very distinct hissing noise. Same noise as before when I found that the Vaccum purge line had been blown off.

You pull highest manifold vacuum when your off the throttle at high revs, and thats what all your accessories run off, if you have a hissing noise while accelerating it has to be before the throttle body as thats were all the vac is. So check pipes from throttle body back, its probably just is induction noise, did you change to a different brand of air filter recently or something like that.

[HamaTime™]

You pull highest manifold vacuum when your off the throttle at high revs, and thats what all your accessories run off, if you have a hissing noise while accelerating it has to be before the throttle body as thats were all the vac is. So check pipes from throttle body back, its probably just is induction noise, did you change to a different brand of air filter recently or something like that.

I've had a K&N Filter in there for a while but that's not the direct cause because it wasn't there as prominently as it is now, and the K&N has been in for over a year.