wheel AUDI A6 1998 C5 / 2.G ATQ Engine Motronic Injection System Servicing Workshop Manual

24-4
Technical data

Engine identification

ATQ (2.8 L / 5V/ 147 kW-engine)
Idle speed
Engine speed cannot be adjusted, it is regulated by idle
stabilization

720 to 820 RPM (front wheel drive)
630 to 730 RPM (all wheel drive)
Engine speed (RPM) limitation
via fuel injector shut-off
about 6800 RPM
Fuel pressure at idle speed Vacuum hose
connected
3.2 to 3.8 bar

Vacuum hose
disconnected
3.8 to 4.2 bar
Residual pressure after 10 min. cold engine about 2.2 bar positive pressure

warm engine about 3.0 bar positive pressure
Fuel injectors Injection stream Dual-hole nozzle / same for all
injectors

Injection quantity (30
s) 90 to 125 ml.

Resistance
(room temperature)
1)
13.5 to 15.5
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24-5


Component locations, overview

Notes:

Other component Locations Fig. 7
, page
Page 24
-11
up to Fig. 12
, page Page
24
-13
.
Component Locations without illustration:
A - Oxygen Sensor (O2S) Behind Three
Way Catalytic Converter (TWC) -G130-
with Oxygen Sensor (O2S) Heater 1 -
Z29-
Bank 2, sensor 1Accessible from below after vehicle has
been lifted
B - Oxygen Sensor (O2S) 2 Behind Three
Way Catalytic Converter (TWC) -G131-
with Oxygen Sensor (O2S) Heater 2 -
Z30- Bank 2, sensor 2Accessible from below after vehicle has
been lifted
C - Leak Detection Pump (LDP) -V144-Below the rear left wheelhousing liner
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24-27

Basic Settin
g
Q
Input display group number XXX

When indicated on display:
- Press buttons -0-, -5- and -6- to select "display group number 056" and press -Q-
button to confirm input.
System in Basic Setting 56
1
2
3
4

When indicated on display:
- Check whether the engine speed in display field 1 (actual engine speed) is within
tolerated range.

Display fields

1 2 3 4
Display group 056: Idle stabilization with engine at idle and operating temperature
Display
xxx /min
xxx /min x.x % X X X X X
Indicated
Engine speed (actual)
Engine speed
(specified) Idle control
Torque
change Operating conditions
Specified
value 720 to 820 RPM
1)
630 to 730 RPM 2) 770 RPM
1)
680 RPM 2) -5 to 5 % 0 0 0 0 0
Notes
If specified value is not obtained
Page 24
-29

Significance of
numbers
Page 24
-29

1) Front Wheel Drive Vehicles
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2) All-Wheel Drive Vehicles
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24-30

Fuel pressure regulator and residual
pressure, checking


Note:
Fuel pressure regulator regulates fuel pressure
according to intake manifold pressure. This
ensures that the pressure drop at the fuel
injectors remains the same for each speed and
load range of the engine.

Special Tools and Equipment

Test requirements:
Repair Manual, Fuel Supply System, Repair Group 20; Fuel supply Front Wheel Drive or fuel supply
- All Wheel Drive

VAG 1318 with VAG 1318/7 adapter, VAG 1318/8 pressure hose with
connectors and VAG 1318/15 adapter Fuel Pump (FP) OK, checking Page 24
-49
.
Fuel Pump (FP) OK, checking: Fuel filter OK Battery voltage at least 12.7 V Vehicles with automatic transmission Selector lever in P or N.
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24-34

- Start engine and let run at idle.

The following malfunction are possible if the pressure does not drop:
Repair Manual, Fuel Supply System, Repair Group 20; Fuel supply
-
Front Wheel Drive or fuel supply
- All Wheel Drive

Note:
Pressure gauge displays the pressure behind the stopcock "intake
manifold side" after the stopcock is closed (in direction of fuel injector, fuel
pressure regulator). If the pressure drops in front of the stopcock (in
direction of fuel tank), the device cannot detect it. For this reason, the
center of this page states "If the pressure does not drop...". - Wait until pressure has dropped, and then switch off ignition.
Simultaneously close shut-off valve of VAG1318 pressure gauge (lever
perpendicular to direction of flow -arrow-).
There is a leak in the threaded connection between the pressure
gauge and the fuel supply line There is a leak at the supply line at fuel tank.There is a leak in the check valve in the Fuel Pump (FP).
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24-58

Basic Settin
g
Q
Input display group number XXX

When indicated on display:
- Press buttons -0-, -0- and -2- to select "display group number 002" and press -Q-
button to confirm input.
System in Basic Setting 2
1
2
3
4

When indicated on display:
- Check specified values for load detection in display fields 3 and 4.

Display fields

1 2 3 4
Display group 002: Air mass taken in with engine at idle and operating temperature
Display xxx /min xx.x %
x.x ms
xxx.x g/s
Indicated Engine speed
(RPM) Load
mean injection time
Air mass
Functional
range 630 to 6800
RPM 12 to 100
% 1.0 to 20.0 ms
1.0 to 150 g/s
Specified
value 720 to 820
RPM
1)
630 to 730
RPM2) 12.0 to
26.0 % 1.0 to 4.0 ms
1.0 to 5.0 g/s
Notes --- ---
If specified value is not obtained:
Evaluation display field 3 Page 24
-
59

If specified value is not obtained:
Evaluation display field 4 Page 24
-
60

1) Front Wheel Drive Vehicles
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2) All-Wheel Drive Vehicles
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