24-3
      
Rules for cleanliness
 
     
When working on the fuel supply/injection 
system, pay careful attention to the 6 
following rules for cleanliness:  
     
Thoroughly clean all connections and the 
adjacent areas before disconnecting. 
     Place parts that have been removed on a clean 
surface and cover them over. Do not use fluffy 
cloths. 
     Carefully cover or seal opened components if 
the repair cannot be completed immediately. 
     Only install clean components: Only unpack 
replacement parts immediately prior to 
installation. Do not use parts that have been 
stored loose (e.g. in tool boxes etc.). 
     When the fuel system is open: Do not work with 
compressed air if this can be avoided. Do not 
move vehicle unless absolutely necessary. 
     Disconnected electrical connectors: Keep clean 
and dry. Connect only when dry. 
Pa
ge 5 of 90 Motronic Multi
port Fuel In
jection 
(MFI
) system, servicin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.1 
24-43
      
Fuel injection volume, fuel injector 
leakage and spray pattern of injectors, 
checking
 
     
WARNING! 
     
Fire hazard! The fuel system is pressurized. 
Before loosening hose connections or 
opening the test connection (to measure fuel 
pressure), place a cloth around the 
connection. Then release pressure by 
carefully pulling off the hose or cap. 
     
Test conditions  
     
Fuel pressure OK; testing   Page 24
-33
 . 
      To reach the fuel rail, the following steps must be 
performed on vehicles with manual transmission 
(without secondary air injection). On vehicles 
with automatic transmission (with secondary air 
injection) are minor differences in the work 
procedure.  
    
Several hoses must now be disconnected:  -  Unscrew bolts on air duct at points indicated (arrows) and remove air 
duct. 
-  Absolute cleanliness must be maintained.
Pa
ge 51 of 90 Motronic Multi
port Fuel In
jection 
(MFI
) system, servicin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.1