Vacuum hose : Audi A4 2.8 V6 Quattro 2000

Chaud

Sr. Member
Joined
Dec 18, 2006
Messages
171
Likes
0
Points
16
#1
The picture attached shows a rubber hose connected to intake manifold next to throttle body. Throttle body has been removed for a better picture. The question is where does the other end of this hose go to? I would appreciate if some one can help me to find that out.
Thanks-Chaud
 

Attachments

The old man

Hero Member
Joined
Aug 3, 2007
Messages
829
Likes
0
Points
16
#2
Have a diagram showing #5 vacuum hose from engine . Don't know if that is what you are looking for or not.
 

Attachments

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,962
Likes
180
Points
63
Location
St-Hyacinthe, Quebec, Canada
#3
Hard to say, but a big vacuum line like that usually connects to the booster. :idea: Could also be for throttle actuator. Here is another view of what old man was so kindly to post. :thx Looking at your picture, and reading vacuum schematics, this is a main vacuum line that supplies many essential parts for this audi to function.

Could also be a coolant line going to heater core. We need more info. Is there any presence of coolant in it? What is the thickness of said "rubber hose". If thin, it is a vacuum line, if thick it is usually for coolant.

Have not worked on a 2000 A4 in years, they are not fun to work on. ouch Can I ask why you are replacing this engine? :idea:

My data base does not seem to have much info. I am not working now, so limited access to proper data base.

Anyway, check it out and post back, we will work through it. 8)
 

Attachments

The old man

Hero Member
Joined
Aug 3, 2007
Messages
829
Likes
0
Points
16
#4
Looks like you have a much better schematic of where all the vacuum lines go than I and he should be able to find where it goes from your drawing if it is indeed a vacuum line.
 

Chaud

Sr. Member
Joined
Dec 18, 2006
Messages
171
Likes
0
Points
16
#5
The vacuum hose looks bigger in the picture because I took a close up. Actually it is 3/8" hose with 1/4" inner hole. It is directly hooked up to a male intake manifold connector with a factory clamp. So it is definitely a vacuum hose.The reason I am at at a loss is that I bought this engine from a junkyard and they chopped this end off wherever it was connected to either inside the engine compartment or firewall. Unfortunately the same hose on the old engine has the same end ripped out due to an accident.So I can't figure out where this hose end was connected to. New engine runs good and has no error codes except P1476 which is emission control system. My theory is this hose end in question is hooked up to LDP (leak detection pump) line which is always under vacuum when car is running. With no vacuum, emission system fails the test. When I installed the engine I did not see any Tee or any remnants of the torn or broken end of male LDP line when looking casually. So where this line from LDP is hiding? If I know the location of LDP I could trace this line and see where it ends. I hope this explanation helps to understand it better than my original post. Thanks
Chaud
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,962
Likes
180
Points
63
Location
St-Hyacinthe, Quebec, Canada
#6
Hi, a 3/8 vacuum line is pretty big. I am surprised you only have LDP code, it is next to evap canistor from what I read of my crappy data base. You can always run your own vacuum line and 3cent tee's at autozone or other similar store.

Is this a shop job or a sideline job. Don't worry we are not the IRS :ROFL

What you could do is visit one of local salvage yards, that has minimal damage and trace those lines, take your cell phone or camera, take pictures, bring it home and presto. Should be a simple fix. I cannot give more info since this car is not in front of me. :thx

Will look into LDP code diagnosis and post back. This stuff takes time for me, so be patient or wait for another to post.
 

The old man

Hero Member
Joined
Aug 3, 2007
Messages
829
Likes
0
Points
16
#7
The LDP is located in either the drivers side rear wheelhouse above the plastic liner, or another program says it is in the R. R. wheelhouse above the plastic liner. So take your pick, but it is back there in one of them.
 

Chaud

Sr. Member
Joined
Dec 18, 2006
Messages
171
Likes
0
Points
16
#8
Nickb2: Thanks for the great idea of visiting junkyards and seeing myself where this hose goes to. First I want to find out where the canister is and then the LDP. To your other question I don't work on the side or have a shop job or consulting of any sort. I am retired and just keeping up the maintenance work on the cars we own. Never worked in car repair business. Replacing Audi's engine was very hard but because of my persistence and optimism I was able to do that. Nevertheless I have to thank you and others who played a big role in my success by offering me the help when I needed it. Thanks
Chaud
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,962
Likes
180
Points
63
Location
St-Hyacinthe, Quebec, Canada
#9
I must say Chaud, which means hot in french btw :ROFL I know what you went through with that 2.8 v6. Not easy. I am impressed you did this after being retired and not a tech. :D

So now it just a question I have to ask, do you live in emission country testing? Cuz if you don't and it drives fine, just leave it alone.

But my concern here is that if you don't get that code fixed, since this a hard code, which means it won't go away and cover any other fault codes, you may have trouble down the line. Cuz if you develop a misfire or cat code or other, that may cause havoc on that engine you worked on, you won't see it cuz a evap code is a priority code due to emission laws.
 

Chaud

Sr. Member
Joined
Dec 18, 2006
Messages
171
Likes
0
Points
16
#10
I traced the vacuum Line from LDP ( Rear back wheel driver side) to engine bay and it was there behind some other stuff. I hooked this line to intake manifold hose with a clamp and cleared the code P1476. I have been driving the car since yesterday and no error code (CEL) showing up on the dash. So I like to thank Nickb2 and the old man for helping me out. Your help is greatly appreciated. Thanks again
Chaud