WallyP

Nicole,

There is one other thing that I would suggest. In your very first post, you said that the flapping occurred when you stopped or when you were pulling away. This suggests that your vacuum source is inadequate.

Look at the vacuum brake booster and find the very small vacuum line attached to the big input vacuum line. A few inches down that line should be a small black and blue vacuum check valve.

With the engine idling, pull the check valve from the small vacuum line on both ends, making sure to remember which way it goes.

Test the valve (by mouth if you have no other way) - it should flow freely in one direction, and not at all in the other direction. If it seems restricted, you can sometimes clean it with brake cleaner - some carb cleaners will eat the plastic, some won't.

Check the amount of vacuum on the line. Reattach the check valve to the line with vacuum, and check the amount of vacuum going thru the valve. If all seems well, reinstall the valve.

A few inches on down the line will be a rubber cross. Check it for cracks and leaks. If you have a MityVac or similar tool (highly recommended!) check the line running over into the front fender for leaks. Since there is a vacuum reservoir in the fender, it will take a LOT of pumps to pull a vacuum - an easier way is to crank the engine with everything hooked up normally, then pull the line to the fender and stick your finger over it to hold the vacuum, then quickly hook it to your tester. The line should hold vacuum indefinitely.

The line running into the firewall is the source line for all of the HVAC functions, and is the same line as the black one that feeds the solenoids.

If there is a line running from the rubber cross up under the intake, it should hold vacuum as well.

As a temporary measure, plug the yellow line coming from the solenoid - no need to plug the upper end, just the solenoid end.

The orange line is the most common leaker...

Nicole

Hi Wally and Roger:

Thanks for the additional info!

Can the vacuum be weak because the yellow line holds no vacuum, causing the recirculation flap to flop?

ROG100

There could be a very small leak in the diaphragm.

IcemanG17

Nicole
When an actuator leaks it diminishes the available vacuum which causes everything else to fail too (thats what happened to me)....It is quite possible that the blue black check valve is bad (everyone I have tested was) or the rubber 4 way "T" is old and leaking (also common)...check those first!

It is odd that the yellow line (footwell) is leaking...mine was fine? When you tested it, it just leaked down fast....could you hear the flapping noise? On my leaky recirc flap, it would move then quickly close because of the leak! It would not move at all by itself. From what I understand the footwell flap-actuator is easy to change once the center console is out or moved. The center flap is nearly impossible in an airbag car (or so I have heard)...pretty much you have to pull the dash :>(

Nicole

Ok, got the solenoid rail out and tested all colored vacuum lines with a better connector than I used the first time. And now I'm more confused than before... they all hold vacuum! And I can hear the flaps moving when I aply vacuum to the lines.

I also found out that the flap I keep hearing when I step on or off the gas at stops is definitely the recirculation flap under the passenger side of the dash. So we know this one is moving by vacuum.

I tried to figure out how to test the solenoids, but haven't yet figured out a procedure that works for me. Should the engine be running, or just the ignition on?

Doing the latter, I can hear the solenoids clicking when I move the lever in the console, but can't tell for sure, if all are clicking at one point or another.

Going back to the garage trying to figure out how to test each individual solenoid...


PS: If none of the actuators leaks, but the footwell flap keeps flopping, is this a sign I have too little vacuum in the system overall?

borland

Nicole,

On my car, the solenoid valve for the hot water heater control valve was bad. Since all of the solenoid valves are the same part number, they are interchangeable and can be swapped out from another location.

The way the solenoid valve works... without 12v power the valve leaks compartment air back to the actuator thru a bleed hole in the side of the valve while at the same time cutting off the vacuum source....with 12V across the terminals the valve allow vacuum from the manifold to the actuate the actuators while at the same time, cutting off the bleed vent on the side of the solenoid valve.

If you think you have a bad solenoid valve, they are easily swapped for testing. Kinda expensive, so you want to test with another one before ordering the part.

You should be using Wally's instructions as a troubleshooting procedure. The best place to start is the source vacuum and then move down the system. However it appear that you are working the other way around.

You initally stated symptoms indicating to me that you had a low vacuum condition; where the likely source of trouble is a leak upstream of the manifold or a bad at the check valve. That's what Wally was suggesting when he said to look under the hood and inspect the check valve and cross connector.

Nicole

Borland:

I guess I'm sometimes slow in understanding logical troubleshooting...

Well, while you were writing this, I was in the garage troubleshooting the lines at the brake booster and 4-way connector. And I might have found something...

The black line that goes along the top of the firewall before disappearing under the air filter box - it has a slow leak. Slow meaning that when I close it up at the console end and apply vacuum on the engine side, I can see the hand of the mityvac's gauge move faster than the hand for the seconds on a clock. There is definitely a problem there - the first I found in my search.

Now comes the question how this line is routed. I cannot see it between the air box and where it comes out under the console. Has anybody replaced this line? It looks like a nasty job to do...

borland

That line might be running to the intake manifold, so that loss of vacuum might be expected without the engine running.

Remember, you want to trace the vacuum lines that lead to the climate control manifold. I think there's a vacuum line diagram on the under the hood emissions label.

Tony

That black line that goes under the airbox may be the heater valve?
Ive seen them white on some cars though?
It could also be for the transmission?
Does it go to the top of the bell housing?
IF it does..DO NOT PULL ON IT...it WILL slide out of the little rubber coupling on top of the torques tube (guess what you have to do to put it right ....or route a new vac line under the car like i did)


As long as you can draw a vacuum on each one of lines to the actuators and they hold indefintiely ...your OK, your out of the woods as far as pulling center consoles, parcel trays..

Nicole

There is a four-way connector - one end has the incoming vacuum and check valve from the brake booster. one goes to the reservoir in the fender, one goes under the intake, and the black line goes towards the middle of the car and disappears under some heater hoses.

According to the WSM the vacuum line for the climate control goes to that four-way connector, so I assume that's the right line. It leaks quite a bit of vacuum, as described above.

From the console side I tried to follow the black incoming line back. All I can see is that it is routed along the drivers side of the HVAC box, then it disappears.

I was under the impression that there is another vacuum connector somewhere in the vincity of the MAF (under the air box) that connects to the transmission. I'm not sure about that, though. But if the leaky line was a transmission line, wouldn't the transmission shift really hard then?

Whatever that black line ends up being, it loses a lot of vacuum that probably starves the climate control and causes the flippin floppin of the recirculation flap.

While I'm certainly glad I won't have to pull console and dash, I'd like to get more input on whether this line is really a direct climate control vacuum line, and what to expect when replacing it.

I tried to load PET on my PC, but it doesn't seem to run on Windows XP, so I can't see any diagrams or parts lists that might indicate what lines and connectors are involved.

I put the solenoid rail and cover as well as the radio back in and buttoned up the passenger side. Waiting with the drivers side until I have a better idea what to expect.

Nicole

No, heater valve vacuum comes from the solenoids in the console (white line)

Most vacuum lines in my engine compartment are white, because they were replaced when I bought the car and had an intake job done. But the ones to the CC and transmission were not replaced at the time, so they are whatever they were from the factory.

Thanks for warning me about that one! I can't rule out that it's the transmission vacuum -- or maybe a line that later splits into transmission and climate control?

Hopefully someone knows and can respond here.

No parcel trays in my car - just knee bolsters, glove boxes, consoles and dashes. Well, one of each, but with lots of nuts, bolts, and screws... I'm definitely glad I won't have to do this!

IcemanG17

Nicole
Did you check the blue/black check valve coming off the brake booster...apply vacuum to the blue side and it should hold steady....if it leaks down then there a problem! How is the condition of the 4 way "T"...all the lines should be held firm...not loose & it shouldn't be too dry or brittle.

The black line you are talking about is the source line for the HVAC solenoids....mine leaks down to about 3 inches (ignition off) and holds steady at 3 inches for some reason? Try testing it with the ignition on? Did the white line on the HVAC manifold hold vacuum (heater valve)? If everything holds and doesn't leak...then it might be a small crack in the rubber piece there is a picture of above? It would be easy to change why the manifold is out! Might as well replace it!

I'm guessing that the blue-black check valve is bad...when you accelerate there is very little engine vacuum and what little there is in the HVAC system gets pulled back through the valve....which would cause the recirc to flap until you let off the gas (creating vacuum) to stablize it!

WallyP

Nicole,

You wrote, "There is a four-way connector - one end has the incoming vacuum and check valve from the brake booster. one goes to the reservoir in the fender, one goes under the intake, and the black line goes towards the middle of the car and disappears under some heater hoses."

The black line that runs toward the firewall is the feed line for the HVAC. The leak that you found shouldn't affect the system a great deal - IF the vacuum supply is adequate. The leak still should be repaired - it's just that it shouldn't be your problem by itself.

The line that runs under the manifold feeds the resonance flap solenoid. It is not unusual for that line to get damaged. Test it and make sure that it holds vacuum. If it does, disconnect it from the solenoid at the left front corner of the engine, and make sure that it flows freely.

You don't say whether you have good flow thru the check valve - that is a critical point...

Nicole

Brian: There are no leaks at the rubber manifold in the console. The rubber is still soft and tight.

Hmmm...I checked the check valve, and it appeared to flow well in one and close well lin the other direction. I might take another look later.

Wally: The line that goes under the intake holds vacuum perfectly. I have to take a look at that solenoid; make sure I find and test it properly. I'll report back.

docmirror

Hi Nicole, Roger and I have had the vac system apart to the Nth degree and we know it pretty well. I'll be out there tomorrow, if you want I can stop by and get it sorted for you. Let me know if you have time Thur nite, or maybe Friday. I've fixed all the vac on my car and they're pretty close. If the flapping is coming from under the pass side footwell, it's the recirc. That is the biggest diaphram and needs the most vac to actuate. If you have a small leak, the recirc may not have enough to fuly hold it when you accel, or when yo are idling. I can look up in there and tell you what's going on and we can hunt it down from that direction backward.

Doc