Hi, In my pursuit to fix my excessive fuel consumption i came across a hose that was broken, but i carnt seem to figure out what it is for. I suspect its possibly a vacuum hose for hvac?. The hose comes off the back of the intake manifold on the same line as brake booster right near the fuel pressure and has a non return valve on it. It seems to go down underneath the abs module and links to another hose which in turn returns to the pcm module . Carnt see where it heads to as it goes under abs. Will post pics. Turning the one way valve around has fixed my vacuum leak and my fuel is returning to normal but what exactly is this hose being used for?. Will try and get some photos uploaded.

i wasnt able to find any information on the web or in the service manuals, im sure its there but not seeing any name. it also has the number 52 on it. Does anybody have a list of vacuum ids for the ba or a diagram?

from memory one hose goes to the vacuum canister mounted under the passenger guard with the other going to the relay that supplies vacuum for the long/short runners valve thingy on the front of the intake manifold.

sorry no idea on the id re hose other than maybe goes by internal size?.

Based on your description, it could indeed be a vacuum hose related to the HVAC system, especially if it’s connected to the intake manifold and has a non-return valve. The fact that turning the one-way valve has fixed your vacuum leak suggests that it plays a role in maintaining proper vacuum levels.

Hey, sounds like you're making good progress! A broken or misconnected vacuum hose can definitely mess with fuel consumption, so that’s a great catch. From the location you described, it does sound like it might be part of the HVAC system. Those vacuum lines are often used to control various flaps and vents, and the non-return valve keeps the vacuum steady, especially when the engine is off or under load. Turning the valve around and fixing that leak probably restored normal vacuum function, which is why your fuel consumption has improved.