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. 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?

[maxwedge]

440 usually would not be not connected to the vent issue, this can be a loose gas cap or anything that causes the closed evap system to not hold vacuum, keep looking for a bad vacuum issue into the control head for the hvac.

[Ruley73]

It sounds like the vacuum hose that goes to your climate control unit has become disconnected from the upper intake on the engine. The unit is stuck in defrost/floor mode and unable to switch modes because no vacuum is present.

The hose connects at the port labeled "TO ACSRY" in the upper left part of the diagram below.

This could also be the source of your P0440 code.

diagram.jpg

[jeranamo]

Originally Posted by Ruley73

It sounds like the vacuum hose that goes to your climate control unit has become disconnected from the upper intake on the engine. The unit is stuck in defrost/floor mode and unable to switch modes because no vacuum is present.

The hose connects at the port labeled "TO ACSRY" in the upper left part of the diagram below.

This could also be the source of your P0440 code.

Attachment 39727

As I said in the initial post, i've already followed that line out to the vacuum ball and it seemed fine. I tried to follow the vacuum line on the other part of the T where it goes into the firewall, but I can't seem to figure out where the vacuum line goes once it seperates from the bundle of wires it comes through the firewall with. I pulled out the HVAC controls and I don't even see a spot for a vacuum line. Where should I be looking for leaks INSIDE the vehicle since the ones under the hood seem ok?

EVAP problem seems to be gone for now... *crosses fingers* I noticed one of the vacuum hoses coming off the EVAP collector was dry rotting pretty badly. As a temporary fix for now I have taped up the hose where it connects with electrical tape. I also messed around with the gas cap (which is an aftermarket one installed by previous owner). Hopefully the EVAP problem is gone... now I just need to figure this HVAC mess out.

[jeranamo]

Would a clogged or leaking PCV system cause my vents not to switch over like this? The car runs kinda rough at idle and I did notice when I did some work on the car a while back that the grommet on the PCV to TB was torn pretty badly and so was the grommet on the other tube - the one that goes from the air box hose to the rear valve cover. In the area where that one connects to the valve cover, that grommet was also bad. I installed them as is anyway with some silicone applied to "repair" the problem. If either of these tubes have a leak, would it cause issues such as this? I guess it could make sense because the PCV to TB tube also connects to the EVAP purge valve.

EDIT: I know the part number for the PCV to TB, but as far as the other goes, is ACDELCO 24504913 the correct one? I cannot find a picture of this part number anywhere.

[Ruley73]

Originally Posted by jeranamo

As I said in the initial post, i've already followed that line out to the vacuum ball and it seemed fine. I tried to follow the vacuum line on the other part of the T where it goes into the firewall, but I can't seem to figure out where the vacuum line goes once it seperates from the bundle of wires it comes through the firewall with. I pulled out the HVAC controls and I don't even see a spot for a vacuum line. Where should I be looking for leaks INSIDE the vehicle since the ones under the hood seem ok?

EVAP problem seems to be gone for now... *crosses fingers* I noticed one of the vacuum hoses coming off the EVAP collector was dry rotting pretty badly. As a temporary fix for now I have taped up the hose where it connects with electrical tape. I also messed around with the gas cap (which is an aftermarket one installed by previous owner). Hopefully the EVAP problem is gone... now I just need to figure this HVAC mess out.

I guess I'm not sure what you are referring to as the "vacuum ball". I thought you were referring to the charcoal canister located in the back of the car because it is often round (like a ball) and holds a vacuum.

There are no vacuum lines that go to the control panel. The control panel simply tells an array of corresponding electric solenoids to open or close based on the selected setting. All of the vacuum lines go to the "vacuum/electric solenoid block". The location of this part as mentioned in the electrical diagram simply states "Behind I/P, right of plenum." An educated guess is that it is located in the middle of the I/P either behind the gauge cluster or behind/below the radio/HVAC control panel.

I would attach a pic of the diagram but the file size is too large to be posted and not legible when it is compressed.

[jeranamo]

Originally Posted by Ruley73

I guess I'm not sure what you are referring to as the "vacuum ball". I thought you were referring to the charcoal canister located in the back of the car because it is often round (like a ball) and holds a vacuum.

The vacuum ball is connected to a T that goes to the upper intake plenum and also in through the firewall. I read this is a common spot for leaks so I was simply posting that I had already checked that (though i guess its possible it still could be messed up... i should take it out and fill it with water and see if it leaks anywhere. Yeah the EVAP canister is what had a dried out and mushy hose coming off of it. I taped it up for now. Thanks for providing info as to where the vac control is. It's going to be a bitch to find it as space is really limited in there and I couldn't even fit my hands in places to follow the vacuum line in.

[jeranamo]

CEL is back on. I hate this car.

[jeranamo]

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?

[Ruley73]

Originally Posted by jeranamo

....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?

If the EVAP parts that rely on it are connected to the same tee in which the vacuum source hose is plugged; yes, otherwise no.

Originally Posted by jeranamo

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

The P0440 code is nearly always caused by a bad/missing/loose fuel cap. I have seen a really dirty air filter cause a P0442 code at least a couple dozen times. I suppose in theory it could also trigger the P0440 code too, but the air filter would need to be dirty enough to drastically reduce air flow through intake. This is why it usually causes the P0442 code (less air flow).

[jeranamo]

Thanks. I'll start by fixing the accs vacuum hose (any idea where I can get this tubing? I believe it's 1/8th inch and its hard plastic tubing) and trying a new gas cap and air filter. Since the PCV vacuum tubing goes from valve cover to intake plenum and then to the purge solenoid area would the fact that the part that fits into the intake plenum is loose (directly under the throttle body bracket) would that cause THAT drastic of a leak to throw off the EVAP or is it more likely to be the purge valve solenoid? Just looking for suggestions on where to start so I don't dump money into a car I can't even end up getting to pass emissions.

[Ruley73]

Originally Posted by jeranamo

Thanks. I'll start by fixing the accs vacuum hose (any idea where I can get this tubing? I believe it's 1/8th inch and its hard plastic tubing) and trying a new gas cap and air filter. Since the PCV vacuum tubing goes from valve cover to intake plenum and then to the purge solenoid area would the fact that the part that fits into the intake plenum is loose (directly under the throttle body bracket) would that cause THAT drastic of a leak to throw off the EVAP or is it more likely to be the purge valve solenoid? Just looking for suggestions on where to start so I don't dump money into a car I can't even end up getting to pass emissions.

Yes, if it is loose enough then that vacuum is lost and not applied to the EVAP system. FYI the "EVAP" is not one part but a system of parts. The Purge Valve Solenoid is part of this system. Here is a very informational link.

[jhend82]

As far as the 0440 code goes look at your fuel filler neck. I have that code and I need a new neck because it's rotted and I was told that it's a common problem in the Luminas for them to rot out.

[jeranamo]

Originally Posted by jhend82

As far as the 0440 code goes look at your fuel filler neck. I have that code and I need a new neck because it's rotted and I was told that it's a common problem in the Luminas for them to rot out.

It does look very rusty. I also looked under the car while the car was running and heard a hissing noise. I haven't pinpointed it to an exhaust leak or fuel system leak (no evidence of fuel leaking however) as of yet since I have not had time to put it on jackstands.

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?