Hissing on Fuel Rails L67

[don0xer]

Ive got a hissing noise around the supercharger, most audible on the passenger side around the throttle body. It is also noticable around the driver side also, I am aware that there are vaccuum hoses that run from the fuel line > actuator > around the back of the engine and to the drivers side. Ive looked around at all the hoses (tb/actuator) and made sure theyre on tight and also made sure the purge valve tube is on firmly and also where it goes to the firewall iirc.

Is it normal for the L67 fuel rails to make a small hissing or is there more likely to be a vaccuum leak, even tho there is no error codes? I cleaned TB/IAC about 3 months ago, just replaced the 2 oxy sensors, which braught my fuel consumption from 16.5-17L/100k to 14.5k/100k mainly 90% suburban/city driving. But i jsut dont wanna be losing ~2L/100k for a tiny leak

[sixshooter]

Stick a piece of garden hose in your ear and poke around the engine bay with the other end... that will help narrow down the actual cause of the noise.

[Tonsta V6 S/C]

Heya don0xer - The Hissing Noise you are experiencing is most likely either the sound of the fuel travelling through the fuel rails under high pressure and being regulated and released from the FPR. Sometime this can be hear over and above engine noise if the engine is really quiet. This is quite normal operation but some are noisier than other and can be heard audibly above everything else.

Other things it can be is a vacuum leak. Either one of the vacuum/boost hoses has a leak, broken rubber elbow (very common) or cracked plastic.

Other items to check - 'O' Rings on the Fuel Injector Ends. If these are not in good condition they may not be sealing where the injector slots into the manifold (Ecotec) or Head (Super6) and can cause the hissing sound from vacuum leak.

As Sixshooter mentioned a good way to try and locate where it might be coming from is with the good 'ol garden hose method.

Hope this helps.

Regards

Tonsta

[don0xer]

Im going to do my rocker gaskets soon as i suspect theyre leaking as theres oil pooling in the dents and wells about 2-3cm to the center of the engine from the injectors. ill do the O rings on the injectors while im sussing it out