C5 Tech Corvette Tech/Performance: LS1 Corvette Technical Info, Internal Engine, External Engine, Tech Topics, Basic Tech, Maintenance, How to Remove & Replace
Sponsored by:
Sponsored by:

[UPDATE]HVAC Vacuum Issues (no progress)

Thread Tools
 
Search this Thread
 
Old 07-24-2004, 11:14 AM
  #1  
Buckmaster
Team Owner
Thread Starter
 
Buckmaster's Avatar
 
Member Since: Jun 2000
Location: Just trying to make it through each day.
Posts: 37,636
Likes: 0
Received 0 Likes on 0 Posts
Cruise-In III Veteran
Cruise-In V Veteran
St. Jude Donor '03-'04
Default [UPDATE]HVAC Vacuum Issues (no progress)

OK, I checked ALL vacuum connections (at least I think I did, could have missed something). ALL connections appear to be OK and no visible cracks in any lines. Line on back of manifold appears to be connected fine (there's only one, right?) ALL fuses appear to be OK. I got under the passenger dash and checked all those colored lines (vacuum lines) that plug into that unit (not sure the name) and they are all OK.

My AC is VERY cold, blower/fan is working but it blows equally hard out the vents, floor, and defrost no matter what setting I use on the controls.

Seems to me the "internal" vents/baffles (sp) are stuck in one position. I am CONFUSED. What is the next logical step? What is the next logical malfunctioning part? It has to be a vacuum issue, right?

I need a break...............why can't my car be perfect? It's not like I can't cool the car down but I want the controls to work when I select a mode....................

TIA
Keith
Old 07-24-2004, 04:54 PM
  #2  
Buckmaster
Team Owner
Thread Starter
 
Buckmaster's Avatar
 
Member Since: Jun 2000
Location: Just trying to make it through each day.
Posts: 37,636
Likes: 0
Received 0 Likes on 0 Posts
Cruise-In III Veteran
Cruise-In V Veteran
St. Jude Donor '03-'04
Default

ttt
Old 07-24-2004, 07:25 PM
  #3  
Bill Curlee
Tech Contributor

Support Corvetteforum!
 
Bill Curlee's Avatar
 
Member Since: Dec 1999
Location: Anthony TX
Posts: 32,736
Received 2,180 Likes on 1,583 Posts
CI 6,7,8,9,11 Vet
St. Jude Donor '08

Default

I will take a look in the service manual later tonight and see what it recommends!

Look for a post late tonight!

Bill
Old 07-24-2004, 07:54 PM
  #4  
Buckmaster
Team Owner
Thread Starter
 
Buckmaster's Avatar
 
Member Since: Jun 2000
Location: Just trying to make it through each day.
Posts: 37,636
Likes: 0
Received 0 Likes on 0 Posts
Cruise-In III Veteran
Cruise-In V Veteran
St. Jude Donor '03-'04
Default

Originally Posted by Bill Curlee
I will take a look in the service manual later tonight and see what it recommends!

Look for a post late tonight!

Bill
Bill
Is the black vacuum line you refer to in the other thread look like a black wire? Very very thin in diameter? If it does, I cannot see that line in the back of the manifold.....so maybe that is missing and is my problem. Does that black wire looking line literally plug into the manifold? Or is just behind the manifold somewhere? I see the black rubber tubing that comes out of the manifold but it is larger and does not look like a black wire........it is about the diameter of a nickel or so......
Old 07-24-2004, 08:56 PM
  #5  
Bill Curlee
Tech Contributor

Support Corvetteforum!
 
Bill Curlee's Avatar
 
Member Since: Dec 1999
Location: Anthony TX
Posts: 32,736
Received 2,180 Likes on 1,583 Posts
CI 6,7,8,9,11 Vet
St. Jude Donor '08

Default

I have digital pictures of the vacuum line. I need you to e-mail me at:

bill327@msn.com so I can send them to you!!
Old 07-24-2004, 09:38 PM
  #6  
LoneStarFRC
Team Owner
 
LoneStarFRC's Avatar
 
Member Since: May 2001
Location: Dear Karma, I have a list of people you missed.
Posts: 36,836
Received 226 Likes on 213 Posts
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16

Default

Keith,
Have you ever had a battery replaced due to leaking, etc? Have you checked the vacuum lines under the battery? BTW, the thin black vacuum lines are nylon and kind of stiff. (They resemble about a 14 to 16 ga wire in size.) They are susceptible to battery acid damage. If you haven't done so already, just pull your R/F wheel off and then remove the small plastic close-out panel at the backside of the wheelwell. This will give you a good view under the battery. HTH

Robert
Old 07-24-2004, 10:10 PM
  #7  
tryme
Instructor
 
tryme's Avatar
 
Member Since: Sep 2002
Location: victoria tx
Posts: 119
Likes: 0
Received 0 Likes on 0 Posts
Default ac

on the drivers side just before the left actuator is the vacuum valve that controls the air direction that you are talking about also on the doors that open to change air flow on the outside where they come out of the case they have some little spring on them to keep them going in the right direction it could be alot of things it just depends on how bad you want to tear your car apart to find out what is wrong.

p.s. the doors inside the case are not the problem.

allan
Old 07-24-2004, 10:36 PM
  #8  
Buckmaster
Team Owner
Thread Starter
 
Buckmaster's Avatar
 
Member Since: Jun 2000
Location: Just trying to make it through each day.
Posts: 37,636
Likes: 0
Received 0 Likes on 0 Posts
Cruise-In III Veteran
Cruise-In V Veteran
St. Jude Donor '03-'04
Default

Originally Posted by LoneStarFRC
Keith,
Have you ever had a battery replaced due to leaking, etc? Have you checked the vacuum lines under the battery? BTW, the thin black vacuum lines are nylon and kind of stiff. (They resemble about a 14 to 16 ga wire in size.) They are susceptible to battery acid damage. If you haven't done so already, just pull your R/F wheel off and then remove the small plastic close-out panel at the backside of the wheelwell. This will give you a good view under the battery. HTH

Robert
No leaking battery ever. I will remove the RF tire tomorrow and look inside the panel...........I did remove the battery and the battery tray but honestly it was hard to see anything going on. I could see teh small black line and I lost sight of it as it went under the RF fender...maybe it is compromised under there..............If this small black line plugs into the back of the manifold somewhere that could be the problem too since I cannot see any line back there. Thank you for the help...............ARGH!!!!!!
Old 07-24-2004, 10:37 PM
  #9  
Buckmaster
Team Owner
Thread Starter
 
Buckmaster's Avatar
 
Member Since: Jun 2000
Location: Just trying to make it through each day.
Posts: 37,636
Likes: 0
Received 0 Likes on 0 Posts
Cruise-In III Veteran
Cruise-In V Veteran
St. Jude Donor '03-'04
Default

Originally Posted by Bill Curlee
I have digital pictures of the vacuum line. I need you to e-mail me at:

bill327@msn.com so I can send them to you!!

I did send you an e-mail earlier from silvervette01@hotmail.com.....
Old 07-24-2004, 10:38 PM
  #10  
Buckmaster
Team Owner
Thread Starter
 
Buckmaster's Avatar
 
Member Since: Jun 2000
Location: Just trying to make it through each day.
Posts: 37,636
Likes: 0
Received 0 Likes on 0 Posts
Cruise-In III Veteran
Cruise-In V Veteran
St. Jude Donor '03-'04
Default

Originally Posted by tryme
on the drivers side just before the left actuator is the vacuum valve that controls the air direction that you are talking about also on the doors that open to change air flow on the outside where they come out of the case they have some little spring on them to keep them going in the right direction it could be alot of things it just depends on how bad you want to tear your car apart to find out what is wrong.

p.s. the doors inside the case are not the problem.

allan
Sorry to sound uneducated.......where exactly is the "actuator" on the drivers side? In the engine compartment area? Near the manifold? I am willing to do whatever it takes to fix this Thank you for the help....
Old 07-25-2004, 12:10 AM
  #11  
tryme
Instructor
 
tryme's Avatar
 
Member Since: Sep 2002
Location: victoria tx
Posts: 119
Likes: 0
Received 0 Likes on 0 Posts
Default a/c

the actuator is behind the dash on the drivers side of the a/c system don't take this the wrong way but if you don't have much mechanic experience you might not want to start taking the dash apart. and to find the vacuum lines they are talking about pull the battery out of the car and get a flash light and look in where the battery goes and towards the lower fender and door area you will see a valve and the vacuum lines.
Old 07-25-2004, 08:57 AM
  #12  
runamuk
Le Mans Master
 
runamuk's Avatar
 
Member Since: Jul 2002
Location: Slave to the evil empire
Posts: 7,364
Received 3 Likes on 2 Posts
Cruise-In V Veteran
St. Jude Donor '04

Default

Originally Posted by Buckmaster
Bill
Is the black vacuum line you refer to in the other thread look like a black wire? Very very thin in diameter? If it does, I cannot see that line in the back of the manifold.....so maybe that is missing and is my problem. Does that black wire looking line literally plug into the manifold? Or is just behind the manifold somewhere? I see the black rubber tubing that comes out of the manifold but it is larger and does not look like a black wire........it is about the diameter of a nickel or so......
The large vacuum line your talking about sounds like the one for the brake booster and the small nylon vacuum line should be right next to it, with the intake removed look around it should be right there, you ill need to reconnect this to the intake.
Old 07-25-2004, 09:26 AM
  #13  
robl45
Melting Slicks
 
robl45's Avatar
 
Member Since: Mar 2003
Location: Deerfield beach Fl
Posts: 2,015
Likes: 0
Received 0 Likes on 0 Posts

Default

you need to diagnose theproblem first. like I said in the other thread, drop the panel under the glove box and find the black wire, disconnect it at its connector near the manifold with all the colored vacuum tubes. Then apply vacuum to the manifold end of the line with a pump or your mouth, if things work with vacuum then the black line is your problem, if not, more troubleshooting.
Old 07-25-2004, 12:32 PM
  #14  
Buckmaster
Team Owner
Thread Starter
 
Buckmaster's Avatar
 
Member Since: Jun 2000
Location: Just trying to make it through each day.
Posts: 37,636
Likes: 0
Received 0 Likes on 0 Posts
Cruise-In III Veteran
Cruise-In V Veteran
St. Jude Donor '03-'04
Default

Originally Posted by runamuk
The large vacuum line your talking about sounds like the one for the brake booster and the small nylon vacuum line should be right next to it, with the intake removed look around it should be right there, you ill need to reconnect this to the intake.
I have CHECKED EVERYTHING (I think) and this has to be the issue. I am going to buy a mechanics mirror today and see if I can see it back there. I am confused where it plugs into the manifold though. Hopefully the mirror will reveal this. The line is so small..............

Since I had manifold work this seems to be the culprit......Thanks everyone for the help. BTW: I am somewhat mechanically inclined....just not re-building the motor and such
Old 07-25-2004, 01:40 PM
  #15  
Buckmaster
Team Owner
Thread Starter
 
Buckmaster's Avatar
 
Member Since: Jun 2000
Location: Just trying to make it through each day.
Posts: 37,636
Likes: 0
Received 0 Likes on 0 Posts
Cruise-In III Veteran
Cruise-In V Veteran
St. Jude Donor '03-'04
Default

Originally Posted by robl45
you need to diagnose theproblem first. like I said in the other thread, drop the panel under the glove box and find the black wire, disconnect it at its connector near the manifold with all the colored vacuum tubes. Then apply vacuum to the manifold end of the line with a pump or your mouth, if things work with vacuum then the black line is your problem, if not, more troubleshooting.
OK....just did the "SUCK" test and it is 100%, without a doubt a vacuum issue. When I SUCKED on the main line under the passenger dash it closed and redirected the vents. I removed the tire and wheelwell covers and see the lines and they ALL look good. I removed the battery and the battery tray and the lines look good. They look good under the dash. It HAS TO BE the manifold connection. I CANNOT see where it plugs into the manifold

My manuals do NOT show where the black line plugs into the manifold This is killing me
Old 07-25-2004, 01:47 PM
  #16  
Bill Curlee
Tech Contributor

Support Corvetteforum!
 
Bill Curlee's Avatar
 
Member Since: Dec 1999
Location: Anthony TX
Posts: 32,736
Received 2,180 Likes on 1,583 Posts
CI 6,7,8,9,11 Vet
St. Jude Donor '08

Default

I'm going to lunch/dinner and when I get back I will get the mirror out and see if I can use it to take a DIGITAL picture of the fitting.
I do not know if it will work but i will try! Check back around 5-5:30 PM for a post from me!

Bill
Old 07-25-2004, 02:06 PM
  #17  
MrEracer
Burning Brakes
 
MrEracer's Avatar
 
Member Since: Sep 2001
Location: Aguila AZ
Posts: 1,173
Likes: 0
Received 1 Like on 1 Post

Default

I just went through this problem... Exactly the same symptoms as yours. My problem was the line coming out of the manifold. Since this is the source of all vacuum it is the first place to look. Also, since you had some work done on the manifold, that is the most likely place where a problem would exist. On the back of the manifold there is a big plastic fitting that plugs into the manifold and has the MAP sensor and a wiring harnnss/connector going into it. It also has a large diameter brake booster line plugged into this fitting. As part of this fitting there is a small vacuum port that points toward the passenger side. It has a 90 degree rubber vacuum connection coming out of it that points towards the firewall. The black plastic vacuum line, about 3/16" in diameter, plugs into this rubber connection. I have found that the black plastic line is sometimes too short and is easily pulled out of the 90 degree rubber fitting. In my case I had to use an extender line a couple of inches long to get enough length to not be pulled out.
From your discription I am 99% sure this is your problem.
This is very difficult location to work on with the mainfold in place. If you can remove the mainfold bolts and slide the manifold forward a few inches it will be easier to see and work on. Hope this helps and good luck.
Shirl
SDRE

Last edited by MrEracer; 07-25-2004 at 02:09 PM.

Get notified of new replies

To [UPDATE]HVAC Vacuum Issues (no progress)

Old 07-25-2004, 02:15 PM
  #18  
robl45
Melting Slicks
 
robl45's Avatar
 
Member Since: Mar 2003
Location: Deerfield beach Fl
Posts: 2,015
Likes: 0
Received 0 Likes on 0 Posts

Default

At least you know what theproblem is, now you just have to plug the line back into the manifold as that appears to be your problems. I cut out the acid eaten part of my line and replaced it with some rubber vacuum hose and my HVAC is working correctly for a change. God damn leaking batterys. What a pain in the A*S this was this weekend.
Old 07-25-2004, 02:21 PM
  #19  
Buckmaster
Team Owner
Thread Starter
 
Buckmaster's Avatar
 
Member Since: Jun 2000
Location: Just trying to make it through each day.
Posts: 37,636
Likes: 0
Received 0 Likes on 0 Posts
Cruise-In III Veteran
Cruise-In V Veteran
St. Jude Donor '03-'04
Default

Originally Posted by MrEracer
I just went through this problem... Exactly the same symptoms as yours. My problem was the line coming out of the manifold. Since this is the source of all vacuum it is the first place to look. Also, since you had some work done on the manifold, that is the most likely place where a problem would exist. On the back of the manifold there is a big plastic fitting that plugs into the manifold and has the MAP sensor and a wiring harnnss/connector going into it. It also has a large diameter brake booster line plugged into this fitting. As part of this fitting there is a small vacuum port that points toward the passenger side. It has a 90 degree rubber vacuum connection coming out of it that points towards the firewall. The black plastic vacuum line, about 3/16" in diameter, plugs into this rubber connection. I have found that the black plastic line is sometimes too short and is easily pulled out of the 90 degree rubber fitting. In my case I had to use an extender line a couple of inches long to get enough length to not be pulled out.
From your discription I am 99% sure this is your problem.
This is very difficult location to work on with the mainfold in place. If you can remove the mainfold bolts and slide the manifold forward a few inches it will be easier to see and work on. Hope this helps and good luck.
Shirl
SDRE
Shirl
This HELPS a bunch. This HAS TO BE the problem. Your description really helps as I wasn't looking for the 90 degree peice on the passenger side. I will look again and see if I can see it. It has to be back there somewhere EVERYTHING else looks good as far as I can see and the fact that the vacuum is supplied by the manifold makes perfect sense and after my "test" of sucking on the main connection under the dash.....it sort of confirms it. Back to work THANK YOU everyone for the continued help.........

Bill, I will check back. If you can get a pic that would be great...thank you.....
Keith
Old 07-25-2004, 02:28 PM
  #20  
Evil-Twin
Team Owner

 
Evil-Twin's Avatar
 
Member Since: Mar 2001
Location: small town in S.E Pa. PA
Posts: 21,325
Received 3,812 Likes on 1,925 Posts
St. Jude Donor '03-'04

Default

Originally Posted by Buckmaster
Shirl
This HELPS a bunch. This HAS TO BE the problem. Your description really helps as I wasn't looking for the 90 degree peice on the passenger side. I will look again and see if I can see it. It has to be back there somewhere EVERYTHING else looks good as far as I can see and the fact that the vacuum is supplied by the manifold makes perfect sense and after my "test" of sucking on the main connection under the dash.....it sort of confirms it. Back to work THANK YOU everyone for the continued help.........

Bill, I will check back. If you can get a pic that would be great...thank you.....
Keith
if you look at my tech tip on replacing the oil pressure sensor you will see my post on that small 1/8 in vacuum line... it plugs into an L shaped black rubber nipple.,. on the back of the intake manifold... this vacuum line is used to control the ac doors... it goes to a vacuum manifold.. if this line is removed your ac doors wont work..

Last edited by Evil-Twin; 07-25-2004 at 02:31 PM.


Quick Reply: [UPDATE]HVAC Vacuum Issues (no progress)



All times are GMT -4. The time now is 08:26 AM.