Complete Vacuum Diagram for Jetta TDI 1998

GiGGer

Veteran Member
Joined
Sep 19, 2003
Location
Quebec
TDI
GTI TDI 130
I am looking for the complete vacuum diagram. according to Mitchell OnDemand, i'm plugged correctly as for the N75 valve but my actual boost has problems reaching the specified boost, which will cause limp mode on 5th gear.

Thanks
 

euromade

Veteran Member
Joined
Apr 20, 2006
Location
MI, USA
TDI
Back to the gasser world
would this work on a 96 passat? or better yet do you have one of these diagrams for my passat?
 

wndboy

Well-known member
Joined
Jul 4, 2008
Location
Brownsville Texas
TDI
2002 Jetta 1.9 ALH
is this the same diagram for a VW 1998 jetta TDI? I just had my engine rebuilt and we are having problems figuring out the vacuum lines.

Thanks,
 

TonyJetta

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Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
wndboy said:
is this the same diagram for a VW 1998 jetta TDI? I just had my engine rebuilt and we are having problems figuring out the vacuum lines.

Thanks,
1998 or 1998.5?

The early is an AHU; Later is and ALH

This diagram should be fine for the AHU.

Tony
 

wndboy

Well-known member
Joined
Jul 4, 2008
Location
Brownsville Texas
TDI
2002 Jetta 1.9 ALH
TonyJetta said:
1998 or 1998.5?

The early is an AHU; Later is and ALH

This diagram should be fine for the AHU.

Tony
Not sure what engine I have. What is the difference between the AHU and the ALH? How do I tell which one I have? If I have the ALH engine, does anyone have the diagram or schematic for this one?
Thanks again,

wndboy
 

TonyJetta

Top Post Dawg
Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
wndboy said:
What is the difference between the AHU and the ALH?
There are several subtle differences. Motor mounts, vacuum pump, injection pump, and many others that I am not aware of.

wndboy said:
How do I tell which one I have?
Look on the timing belt cover; see the barcode? Also, the ALH intake manifold points to the Passengers side (like this pic); AHU/1Z points to the drivers side.



wndboy said:
If I have the ALH engine, does anyone have the diagram or schematic for this one?

 

P2B

Top Post Dawg
Joined
Jan 11, 2006
Location
Toronto & Muskoka, Canada
TDI
2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
TonyJetta said:
1998 or 1998.5?

The early is an AHU; Later is and ALH

This diagram should be fine for the AHU.

Tony
The AHU to ALH changeover occured in 1999 for Jettas - 1999 Jetta was Mk3 body AHU motor and 1999.5 was Mk4 ALH.

Simon
 

wndboy

Well-known member
Joined
Jul 4, 2008
Location
Brownsville Texas
TDI
2002 Jetta 1.9 ALH
Still having issues trying to figure out my vacuum lines. Vacuum diagrams posted here have helped but does not list all vacuum hoses for this engine. In question is this part that is located on the right bottom side of engine (AHU) 1998 TDI, right next to manual transmission. One large black hose goes from this part to the brake master cylinider. Within this large black hose their is a small black plastic piece with 2 tits where two vacuum hoses go. One of the vacuum hoses is attached to a short black piece of vaccum hose and connects to a green plastic hose and runs to another short piece of vacuum hose that connects to another black plastic piece with 2 tits and an electrical connection at the right side of the fire wall (Just left of the raidiator reservour) Is this connection right? Where does the other vacuum hose comming from the first black piece on the brake master cylinder hose go?
**I realize this is long and drawn out but I tried to be as descriptive as possible. Thanks
 

P2B

Top Post Dawg
Joined
Jan 11, 2006
Location
Toronto & Muskoka, Canada
TDI
2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
wndboy said:
Still having issues trying to figure out my vacuum lines. Vacuum diagrams posted here have helped but does not list all vacuum hoses for this engine. In question is this part that is located on the right bottom side of engine (AHU) 1998 TDI, right next to manual transmission.
That is the vacuum pump.
One large black hose goes from this part to the brake master cylinider. Within this large black hose their is a small black plastic piece with 2 tits where two vacuum hoses go. One of the vacuum hoses is attached to a short black piece of vaccum hose and connects to a green plastic hose and runs to another short piece of vacuum hose that connects to another black plastic piece with 2 tits and an electrical connection at the right side of the fire wall (Just left of the raidiator reservour) Is this connection right?
Yes. that's how it's connected on my car. I believe it's part of the HVAC system, but not sure of the exact function. There should be a white plastic vacuum hose connected to the second tit which goes through the firewall.
Where does the other vacuum hose comming from the first black piece on the brake master cylinder hose go?
That one goes to the EGR control valve (N18) - shown on the diagram above the N75 and below the ECU, the hose labeled vacuum supply

Simon
 

HueyTDI

New member
Joined
Nov 24, 2008
Location
Abbotsford, BC
TDI
2003 Jetta 1.9
hope i can get help quickly, on the ALH hose diagram 1.9L, there is hose that is connecting to the top of the air cleaner cover. it is leading from the EGR. i do not have a tit there or anywhere on the cover. i cannot locate any tit in the area to where this hose needs to connect. is it possible the hose is to be left as is? i have a 2003 tdi without turbo.
 
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TonyJetta

Top Post Dawg
Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
If it's like the TDI motors, it's just an atmosphere vent, for closing the EGR valve.

You may want to wrap a rag around it to prevent it from sucking in any contaminants...like a filter.

Tony
 

P2B

Top Post Dawg
Joined
Jan 11, 2006
Location
Toronto & Muskoka, Canada
TDI
2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
HueyTDI said:
hope i can get help quickly, on the ALH hose diagram 1.9L, there is hose that is connecting to the top of the air cleaner cover. it is leading from the EGR.
The hose connection from the EGR and N75 solenoids to the airbox on a 2003 Jetta TDI is circled below - is that what you mean?



i have a 2003 tdi without turbo.
What happened to your turbo?

Simon
 
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