P0440 and no air blowing through vents

[jeranamo]

I have a 1996 Lumina LS with the 3.1L. The check engine light came on recently and triggered P0440 - EVAP Problem. I noticed a dry rotting line coming off the EVAP canister, so for now I have taped that up. Also made sure gas cap was tight and put everything back together and started it up. No CEL... for about a day. Unfortunately it is back now...

The vents are also not blowing except for on the floor and defrost. I assumed this meant vacuum leak, however I cannot find a leak or missing hose anywhere, except I did notice directly to the left of the evap purge solenoid there is another... object attached to it. I reached my hand down there and there is a rubber elbow with a hole in the end... is this just a waste tube of some sort or does a vacuum line go here... sorry impossible to get pics...

I have already checked the line coming from the intake manifold to the vacuum ball, t-fitting doesnt seem to be leaking either... I'm at a loss here... why would I be getting a P0440 AND no air flowing through vents? I can only assume the 2 problems are related since they happened at the same time.

[pocket-rocket]

I think you are on the right path. One way to track down a vacuum leak is to take a propane torch (unlit) and run the gas over the vacuum hoses. When the idle speed changes, you found your leak. As for the elbow you found, I've no clue what it's for since I don't have a 96, but yeah, the floor and defrost deal tells me your HVAC controls aren't getting vacuum like they are supposed to.

[bszopi]

I am 99% sure that elbow is just a drain or vent of some kind. I remember seeing it on mine when I was messing with it many moons ago.

Oh yeah, and welcome to the site!

[jeranamo]

Thanks guys, that information does help.

Here's an update. I took off the line coming directly from the intake mani (accs) and also from at the T. That particular line is completely clogged... Immediately noticed a change in idle (got really rough) when i pulled that tube off. I put my finger over the hole and disconnected that line, again, the one that goes from the intake mani to the T. This is good news as far as the HVAC system goes. The question is, would lack of vacuum in the manifold due to a clogged ACCESSORY vacuum line cause other things that rely on vacuum (such as the EVAP) to malfunction/throw a code? I'm going to purchase a length of vacuum hose to replace the clogged one and find out, but just for "words of encouragement", does this sound plausible as to why the ECM is throwing a EVAP code?

EDIT: Also, would an extremely dirty air filter trigger an EVAP code as well?

[86FieroSEv6]

No, an extremely dirty air filter will not '440. I would check the purge control solenoid for proper vacuum supply and that the other line going to the body (the one that goes back to the canister system) is okay. The purge solenoid on these cars is mounted on the back of the ignition system support bracket (best that I can recall at the moment).

[jeranamo]

HVAC problem solved, EVAP issue still at large.

Another thing I should mention, the car has always had a funky fuel gauge since we bought it, but now it seems to drop and increase throughout the drive. Usually when accelerating, the needle goes up, and then upon reaching a stop light and having the engine idle, it will drop. Is this a bad sensor/sender or does this also indicate a pressure leak in the system?

[pocket-rocket]

It could be broken baffles in the tank, allowing the sending unit to see a greater change in fuel level.