The New 20V Turbo Engine
I
i
AS:
CERTIFIED
The New 20V Turbo Engine
for the
Audi 200 Quattro
WE ENCOURAGE PROFESSIONALISM
THROUGH TECHNICIAN CERTIFICATION
Service Training
Self-Study Information
Table of Contents
Introducti on .............. ........................................................................ .... ............................. 2
20-Valve Turbo Engine ....... ........................................................... ................ ................... 3
Cooling System ......... .......................................... ..................... .......... ............................... 5
System Lay out ........................... ................. .............. ......................... ........................ ........ 6
Motronic Control Unit ................... ............................ ................................ ........................ 8
Adaptive Learning ............................... ........................................ ...................... ................ 9
System Diagra m .............. .................. ......................................................................... ....... 10
Volkswag en of America
Service Training
Printed in We st Germany
Printed 4/90
Part #WSP 52120900
This book is a cooperative effort between V. A. G
Kundendien st Schulung, Wolfsburg, West Germany
and VWoA Service Training, Tro y, Michi gan.
All rights reserved. All information contained
in this manual is based on the latest product
information available at the time of printing. The
righ t is reserved to make changes at any time
without notice . No part of thi s publication may be
reproduced, stored in a reoieval system, or
transmitted in any form or by any means, elec tronic,
mechanical , photocop ying, rec ordin g or otherwi se,
without prior written permi ssion of the publi sher.
This includes text, figures and tables.
Always check P-circulars and the microfiche system
for information that may super sede any information
included in this bookl et.
Sensors/ Actuato rs
Hall Sender ................................................................................................ ......... ....... 12
Reference Sensor/ Speed Sen sor ................................................................................ 12
Air Mass Sen sor ............. ............... ............ ..................... .................. .................... ..... 13
Throttle Valve Potentiometer And Idle Switch ................................. ........................ 14
Intake Air Temperature Sensor ............. ......... ............. .............. ........ ........................ 15
Coo lant Temperature Sensor ...................................... .......................................... ..... 15
Knock Sensor I And II ........................... .................... .............. .......................... ....... 16
Oxygen Sensor ..................... .............................. ....................... :........ ,...................... 16
Altitude Sensor ................... .................... ...... ............ ,......................................... ....... 17
Intake Manifold Pressure Sensor ................................ , .......... .................... ................ 17
Multi-F unctio n Temperature Sensor ............ ................................................ ......... .... 18
Idle Stabilizer ........................... .............. .................... ................................ ........ ....... 19
Carbon Canister Frequen cy Valve .................... ..................... .......................... ......... 19
Fuel Injectors ......... .................................. ......................................... ......................... 20
Ignition Coil, Output Stage And Distribut or ............................................. ................ 20
Wastegate Frequency Valve .................. ......... .................................................. ......... 21
Fuel Pump Relay/Fuel Pump ............................................... .......... ....................... ..... 21
Fuel System ................. ........................................................ .................................. ............ 23
Fuel Tank Venti lation System .................. ............................. ........................ ............ ........ 26
Boost Pressure Control ............ ................................. .................... ..................... ............... . 28
Idle Stabilization ....... .............. .............................. ............ ................................................ 31
Knock Control ............................. ............ ....................................... ................. .................. 32
Connector Assignments ................ ............................................................. ...................... .. 33
Power Supply ......... .............. .............. ............................................ ................ ................... 34
Grounds ............... ............................................ .................. .................... .............. .............. 35
Wiring Diagram ........................... .................... ...................... .......... .............................. .... 36
Self-Diagnosis With V.A.G 1551 ......... ........................ ................ ...................... .............. 38
Introduction
Audi is introducing a new engine for the 1991 200
Quattro. The engine is a 20-valve 5-cylinder turbo
with Motronic Engine Management System.
The new engine is based on the 5-cylinder 2.2 liter.
Its main features are a water-cooled turbo and
20-valve cylinder head. The engine can deliver
maximum torque of 228 foot-pounds at 1,950 rpm
and peak power of 217 HP is obtained at 5,700 rpm.
20V Turbocharged Engine
With the maximum torque developed at 1,950 rpm,
turbo lag has been reduced to a point where the
engine's performance range is similar to that of a
normally aspirated engine .
The suspension, brakes , and wheels and tires for the
200 Quattro 20-Valve Turbo are the same as the
Audi V8.
Technical Data
SSP111/2
Type:
5-cylinder in-line turbocharged engine with 4 valves per cylinder
Displacement:
2226 cc
Stroke:
86.4mm
Bore:
81.0 mm
Compression:
9.3:1
Horsepower:
[email protected] 5,700 rpm
Maximum torque:
·[email protected] 1,950 rpm
Engine Management System:
Motronic
Cooling System
20V Turbocharged Engine
"1·
-------------------------------------------
Cooling System
Performance And Torque
1,950 rpm , while the maximum power output of
217 HP is reached at 5,700 rpm. This results in an
extremely wide, engine power range.
The five-cylinder turbocharged 20V engine
develops its maximum torque of an impressive
228 ft.-lbs. at the unusually low engine speed of
A new feature is the cross-flow cooling system for
the cylinder head. The coolant enters the cylinder
head on the exhaust side and exits on the intake
side. This ensures uniform cooling of all cylinders
and all combustion chambers .
400
200
Special control ribs in the water ducts ensure proper
cooling of hot spots around valve seats and the
areas around the spark plugs.
In addition to the above cooling, oil spray jets are
located at the bottom of each cylinder bore to cool
the pistons, and the exhaust valves are filled with
sodium.
Heater co re
360
320
228
Electric
ft.-lbs.
280
140
240
~
Coolant reservoir
200
100
I
I
160
120
Turbocharger
80
Additional radiator
40
0 _.__
__
0
_.___
1000 2000
---1.
___
...__
__
3000
__,_
__
4000
Engine speed (rpm)
____JL...._.._~
5000
0
SSP111/4
SSP111/5
System Layout
System Layout
~.---------------------------------------------------- -------------------------------------------------------
a
F uel filter\.
~--c:n
Fuel pump relay
Carbon canister
frequ ency valve
Throttle valve potentiometer with idle switch
Fuel
tank
Intake air temperature
enso r-~------,
Wastegate
Injector
Hall send er
\\/ astegate
frequency valve
Ignition coil
Carbon canister
Diagnostic connector
Hot wir e
air mass
sensor
Engine speed
sensor
Coo lant temperature
sensor
Altitude sensor
Boost pressure
,-----
--------------
------
© ©©©2
--------
-- ---------------------
J
---- - ----------------
----------------
SSPl 14,'6
-----------
----------1
~
Motronic Control Unit
Adaptive Learning
-.--------------------------------------------"
The Motronic control unit performs the following
functions:
Sequential fuel injection
• Basic fuel mixture control via map in the ECU's
memory
• Starting enrichment
• After-start enrichment
• Warm-up enrichment
• Acceleration enrichment
• Deceleration fuel shut-off
• Engine speed limitation
• Oxygen sensor control
Ignition timing control
• Basic timing control via an ignition map in the
ECU's memory
• Dwell angle control
• Ignition timing correction based on air
temperature
• Start control
• Warm-up correction
• Digital idle stabilization
• Cylinder-selective knock control
Self-Diagnosis
• Monitor sensor inputs
• Monitor outputs
• Fault output via V. A. G 1551
• Display individual values via V. A. G 1551
• Perform output checks
• Emergency mode operation
A system is said to be adaptive when it is capable of
replacing standard control values with modified
values due to changes in operating conditions.
Adaptation by way of example of the lambda
(oxygen) control system:
Oxygen sensor
(lambda probe )
Lambda control possible
Pilot value (basic setting )
Lambda control not possible ---t--,-41----.1
0
Control unit
Boost pressure control
• Boost pressure control via map in the ECU's
memory
• Altitude correction
Idle stabilization
• Idle speed control via map in the ECU ' s memory
with adaptive learning capability
• Starting correction
• Idle speed increase with A/C
Fuel tank ventilation
• Fuel tank vapor flow controlled via map inside
ECU
• Frequency valve operation controlled via map
inside ECU
SSP111/7
For example:
If the mixture is still too rich and the control unit's
When the oxygen sensor senses that the fuel
mixture is too rich, the control unit changes the fuel
mixture to a leaner value by shortening the injector
opening time.
rich limit is exceeded, the control unit will adapt to
this condition and establish a new basic setting.
This new basic setting (pilot valve) will then
be used in both open and closed loop engine
operation. This eliminates the need for periodic
CO adjustments.
System Diagram
...
..
------- --------- -----------------------------------
System Diagram
- - ------------------------------------------------------!,
'
Actuators (final control units)
Sensors (data senders)
Idle stabilizer valve
Hall sender
Ca rbon canister frequency valve
Reference sensor and
engine speed sensor
----------
~1
~
2
Injectors
Air mass sensor
---
~3
4
Throttle valve potentiometer
with idle switch
5
Boost
pressur e
lntak, ,;, t,mpmtu.-.
Coolant temperature
Knock sensors I
~"''"
sensor
~
,______
.,.,
Ignition coil with power stage
and ignition distributor
~ ---Wastegate frequency valve
+ II
Oxygen sensor
Diagnostic connectors
Fuel pump relay and fuel pump
Altitude sensor
...,. ---------------A-d_
d_i-tio_n_a_i_s_ig_n_a_ls----------------
---------------
- -
____________
s_s_P_1_1_1
1_a
_____________________
A_d-di-ti_o_na_1_s_ig_n_a_1s
____________
...;.
Sensors, Actuators
-._i,
.---------------------------------------------
Sensors, Actuators
--------------------------------------,_,,
Hall Sender (G 40)
I
Air Mass Sensor (G 70)
The Hall sender and trigger wheel are located in the
distributor . The trigger wheel has a 40° wide
opening (Hall window).
Trigger wheel
The signal that the Hall sender provides is used to:
• Ignition firing point signal for #1 cylinder when
engine is first started
• Determine injection timing and sequence
• Cylinder reference signal for knock sensors
Substitute function
If the Hall sender fails, the engine cannot be
restarted. If the Hall sender fails when the engine
is running, the engine will continue to run by using
the reference sensor and engine speed sensor
signals, but the ignition timing is retarded 6°.
Hall sender
Temperature compensation
resistor
Platinum wire
A hot wire air mass sensor is located ahead of the
turbocharger and is mounted to the air filter
housing. The sensor is used to measure the air flow
into the engine . The sensor uses a glass-coated, thin
platinum wire to measure the air flow, and contains
no moving parts.
Reference Mark (G 4) and Engine Speed Sensors (G 28)
Engine speed sensor
Both sensors are identical in design and are located
on the left side of the engine compartment, near the
flywheel.
The reference sensor is used by the control unit to
identify crankshaft position. A steel pin is pressed
into the flywheel 62° before TDC for #1 cylinder.
The pin , along with the sensor, generates one signal
per crankshaft revolution.
The speed sensor produces an AC voltage signal by
scanning the teeth of the flywheel. This signal is
used by the control unit to measure engine speed.
Substitute function
If either of the sensors fail, the engine cannot be
started. However, if the reference sensor fails when
the engine is running , the system will use the #1
cylinder signal that was used when the engine was
started.
....
------------------------------------------SSP111/10
,
The sensor uses a baffle screen to reduce air
turbulence at the measuring point .
SSP111/11
for one second each time the engine is switched off.
This is to burn off any possible contamination .
I
The burn-off signal is provided by the Motronic
control unit. Due to this fact, it is important to
remember that the connector plug for the Motronic
control unit must not be removed before 20 seconds
has elapsed after .the ignition has been switched off .
No repairs can be performed to the air mass sensor.
The platinum wire inside the sensor is heated
electrically. An air temperature sensor is used
to determine the amount of current to heat the
platinum wire.
As air flows over the heated wire, the wire is
cooled, which changes the resistance of the wire.
The Motronic control unit uses this resistance
change to calculate air flow volume and air density .
In this way, the actual volume of air is calculated
by its weight or mass. This measurement will not
require any additional corrections because it already
accounts for any possible changes in air temperature
and/or air pressure .
Since contamination of the hot wire surface can
cause inaccurate readings, the hot wire is heated
electrically to a temperature of 1,000°C (1,810°P)
~
Substitute function
If the air mass sensor should fail, the engine will
continue to run under two conditions.
When the throttle is closed (idle switch closed),
the engine runs at the idle ignition timing map and a
preprogrammed amount of air.
When the idle switch is opened (part load), the
ignition timing goes to a fixed position of 20° and
the fuel mixture is leaned. This allows the vehicle to
be driven to the closest dealer .
Sensors, Actuators
Sensors, Actuators
~--------------------------------------------
~•.
------------------------------------------ -:
Throttle Valve Potentiometer (G 69) With Idle Switch (F 60)
Potentiometer
Intake Air Temperature Sensor (G 42)
An idle switch and throttle valve potentiometer are
used on the throttle assembly. The idle switch
closes at approximately 1.3° before the throttle plate
closes. When the switch is closed, this signal is used
to activate the following functions:
An intake air temperature sensor is located in the
intake manifold near the throttle valve housing. It is
used for ignition timing, knock regulation and boost
pressure control. The sensor is a PTC resistor.
The ignition timing adapts to current intake air
temperature. As the intake air temperature
increases, the boost pressure is reduced to prevent
detonation.
• Idle stabilization
• Deceleration fuel shut-off with engine warm and
above 1,400 rpm. Fuel supply is reactivated when
the engine speed falls below 1,200 rpm
Substitute function
• Special ignition map for deceleration
SSP111/13
If the sensor should fail, the ignition timing is
retarded and a replacement value of 40° C is used
for boost regulation.
PTC resistor
CJ
Idle switch
SSP111/12
The throttle potentiometer is connected to the
throttle shaft and is supplied 5 volts. The signal it
provides is used to determine the position of the
throttle plate and the speed of the throttle plate
movement.
The throttle valve potentiometer is only used for
boost regulation. The throttle valve position is a
reference value for the boost control map. Boost
regulation will take place when the throttle plate is
open greater than 35°.
Coolant Temperature Sensor (G 62)
A coolant temperature sensor is located at the back
of the cylinder head. It is an NTC resistor.
•
The sensor is used for ignition timing, injection
timing during cold and hot starting, warm-up
enrichment and idle stabilization.
The Motronic system does not use a full throttle
switch . The control unit detects full load on the
relationship of engine load to engine speed.
Substitute function
Substitute function
If the coolant temperature sensor should fail, a
substitute value is used based on a signal from the
air temperature sensor.
If the idle switch should fail, the idle stabilization
system will not operate.
NT C resistor
If the potentiometer should fail, boost pressure is
controlled mechanically by the wastegate at a lower
value than what is programmed in the ECU.
For example:
• Air temperature greater than 0° C (32°F) - the
substitute value is 80°C (l 76°F)
SSP111/4
·.~--- ------
- - - -------------------------------
~
-
• Air temperature less than 0°C - the substitute
value is the intake air temperature for three
minutes and then switched to 80°C
..
_________
__________________________________
_
, Sensors, Actuators
..,,,,__
Altitude Sensor (F 96)
Knock Sensor I (G 61) And Knock Sensor II (G 66)
Knock sen sor
SSP111/15
Sensors, Actuators
The 20-Valve turbo uses two knock sensors. Knock
sensor I is located next to cylinder #2 and is used
for cylinders #1, #2 and #3. Knock sensor II is
located next to cylinder #4 and is used for cylinders
#4 and#5.
The altitude sensor is located behind the left kick
panel, near the "A" pillar . When there is a change in
the air pressure, the barometric cell moves a sliding
contact over the set of resistors . This informs the
control unit of the current air pressure or altitude.
The use of two knock sensors makes it possible for
the system to be more sensitive to knock.
The altitude sensor is only used for boost pressure
control. At altitudes above 3,300 feet, the boost
pressure is reduced as the altitude is increased . The
reason for this is to avoid overrevving of the
turbocharger.
If knocking is detected for an extended period of
time, the ignition timing is retarded and the boost
pressure is reduced.
Substitute function
Substitute function
Resistor set
Barometric cell
SSPl 11/17
If knock sensor I should fail, the ignition timing
for cylinders #1, 2 and 3 will be retarded by 6°. If
knock sensor II should fail, the ignition timing will
be retarded by 6° for cylinders #4 and 5.
If the sensor should fail , an altitude of 13,124 feet is
assumed and the boost pressure is reduced to its
minimum level.
Intake Manifold Pressure Sensor (G 71)
An intake manifold pressure sensor is used to
measure the amount of boost pressure in the intake
manifold . The sensor is located inside the Motronic
ECU.
Oxygen Sensor (G 39)
A heated oxygen sensor is used for this system. The
sensor is located in the exhaust outlet of the
turbocharger.
Electrical
conn ection
The sensor measures oxygen content in the exhaust
gas and is used to regulate the air/fuel mixture.
A vacuum line from the intake manifold to the
control unit is used to transmit the manifold
pressure ·signal. The ECU converts this signal into
an electrical signal.
Vacuum
The sensor consists of a crystal chip and two semiconductors. The crystal is shaped in such a way that
it allows a small amount of vacuum to be trapped
between the base plate and the crystal.
Substitute funct ion
If the sensor should fail, the engine will run on the
adapted fuel mixture at the point of failure.
Idling
The crystal will flex depending on the amount
of manifold pressure . The two semi-conductors
attached to the top of the crystal sense the fle xing.
Heating
element
Ce rami c sensor
housing
SSP111 / 18
Cr)·st al chip
SSP111/16
___
_________
___________
_______
______
_______
__ -------------------------
,.
- ~i
The flexing of the chip causes the semi-conductors
to alter their shape. This changes the resistance
values of the semi-conductors. The change in
resistance values is used by the control unit to
determine the amount of boost pressure.
------------
- - - ----~
..
~
Sensors, Actuators
'1.
~----
--------
------
---------------------
Sensors, Actuators
---
Multi-Function Temperature Sensor (F 76)
The multi-function temperature sensor is located in
the coolant flange on the cylinder head . This sensor
has several functions:
Idle Stabilizer Valve (N 71)
The idle stabilizer valve for the 20-Valve turbo is a
single winding, rotary-type.
To int ake tube manifold
-ct-
SSP111 / 19
• When coolant temperature exceeds 119°C
(245°F), the boost pressure is reduced
• Engine temperature gauge
• Engine temperature warning light
• Climate control compressor clutch operation
The idle stabilizer consists of a small single winding
electric motor, rotary valve and a return spring
attached to the motor's armature.
Rotar y slide
Return spring
SSP111/20
The motor is operated by a cycled DC voltage
which will cause the armature to work against the
return spring. The duty cycle determines the
position of the rotary valve and the size of the
opening.
I
II
I
Substitute function
Additional Signal: A/C Compressor ON/OFF Signal
Pin #40 at control unit
If the valve should fail, the engine runs with a
constant quantity of air at idle, which is the same
idle spe~d as if the valve was unplugged
electrically.
When the A/C compressor is switched on, a signal
is sent to the Motronic control unit via pin #40 of
the ECU. This signal is used to increase the rest
position (closing value) for the idle stabilizer valve
when the idle switch is open. This function reduces
load slap caused by the NC compressor.
'
Carbon Canister Frequency Valve (N 80)
Vapors from the fuel tank are collected in the
carbon canister. A frequency valve is used to
regulate the flow of fuel vapors that are drawn into
the intake manifold from the carbon canister.
Additional Signal: A/C Compressor Idle Speed Increase Signal
When the A/C is switched on, pin #41 of the ECU
receives a signal that the NC is on. This increases
the duty cycle to the idle stabilizer and raises the
idle speed.
The frequency valve is operated by the Motronic
control unit. The valve is controlled by a duty cycle.
The valve's duty cycle will vary depending on
engine temperature, load and speed.
Pin #41 at control unit
When the engine is off, a check valve stops the flow
of vapors from entering the engine.
Substitute function
SSP111 /21
.'',,.-....
-------------------------------------------~
If power to the frequency valve is interrupted or cut
off completely when the engine is running, vacuum
from the engine will open the check valve to allow
tank ventilation .
----------------- ------------------ ---- -----
..
'!,
Sensors, Actuators
Sensors, Actuators
Fuel Injectors (N 30, N 31, N 32, N 33, N 83)
i
Wastegate Frequency Valve (N 75)
One fuel injector is assigned to each cylinder. Each
injector is located in the intake manifold , ahead of
the intake valve. The injectors are electromagn etic.
The injectors are opened and closed by electrical
pulses from the Motronic control unit.
The wastegate frequency valve is located near the
turbocharger and intake air duct and regulates the
flow of intake manifold pressure to the wastegate. It '
is operated by the Motronic control unit.
The frequency valve is operated by a duty cycle of
0-100%. By regulating the frequency valve's duty
cycle, the control unit can regulate the boost
pressure to match the predetermined value from the
map in the control unit.
en
en
"
Substitute function
SSPl 11/23
Ignit ion Coil (N), Ignition Output Stage (N 70) and Distribu tor (0)
If the wastegate frequency valve should fail, the
boost pressure is controlled at a lower value
mechanically by the wastegate.
Ig nition mil
Fuel Pump Relay (J 17) And Fuel Pump
l>ist rihut or
...
SSP111/22
The fuel pump is located in the fuel tank. The fuel
pump is activated by the fuel pump relay. The
Motronic control unit supplies a ground signal to
the fuel pump relay when the engine speed is
greater than 25 rpm.
lh·lin •ry s ick
An ignition coil with a separate power stage is used
with the Motronic system. The power stage is a
Darlington-type of transistor which switches the
primary current for the ignition coil on and off.
The power stage completes a ground circuit for
terminal #1 of the ignition coil when it receives a
voltage signal from the Motronic control unit.
The distributor is mounted on the end of the
cylinder head and is driven by the intake camshaft.
...
__________________
___________________
..
SSP111/24
lntakl- sidt •
•,!.,_ ___________________________________________
.,.
_
Sensors, Actuators
Fuel System
~.
~----------------------------------------------Additional Signal: Tachometer/Trip Computer
The control unit supplies an engine speed signal for
the tachometer and the trip computer.
The fuel pump located in the fuel tank delivers the
fuel to the injectors via the fuel filter . The fuel
returned from the injectors is routed through the
fuel pressure regulator.
Pin #6 at control unit
Additional Signal: Boost Pressure Indicator
The control unit provides an analog signal to the
trip computer for boost pressure indication.
Pin #31 at control unit
Fuel pump
Additional Signal: Fuel Consumption
The control unit provides a fuel consumption signal
for the trip computer. This signal is calculated
directly from the injection timing.
Tank
SSP111/25
Fuel Pressure Regulator
Pin #32 at control unit
Fuel pressure is regulated by a diaphragm-type
pressure regulator. The pressure regulator maintains
the fuel pressure at approximately 3 bar (43.5 psi)
above intake manifold pressure.
A vacuum line from the intake manifold to the
pressure regulator is used to transmit the varying
intake manifold pressures.
return to the fuel tank to maintain correct fuel
pressure.
When the engine is under full load, the fuel
consumption is greater. Manifold pressure is
increased due to boost pressure from the turbo. This
pressure closes the diaphragm in the pressure
regulator allowing less fuel to return to the fuel tank
to maintain correct fuel pressure.
For example:
At idle, only a small quantity of fuel is needed to
maintain engine operation. Vacuum from the intake
manifold is applied to the diaphragm and spring in
the pressure regulator which allows more fuel to
·:.:
'·-----------------------------------------------
When the engine is switched off, the diaphragm in
the pressure regulator is completely closed due to
spring pressure. This creates a holding pressure
between the pressure regulator and the fuel pump.
------------------------------------------------..
'
Fuel
~.
\:----..;...
____________________________________
_
System
Pressure Regulator
High intake manifold pressure
(boost pressure)
From injectors
Fuel System .
Injectors
Low intake manifold pressure
(vacuum)
The injectors for the Motronic system are a single
jet nozzle-type. The injectors consist of a valve
housing, needle jet and annature.
~
Return to tank
Idling
Full load
SSP111/26
Sequential Injection
The Motronic Engine Management System uses
sequential injection that is similar to the MPI
system used on the 20-Valve Coupe and 90 Quattro .
The control unit operates the injectors by
completing a ground circuit. The fuel mixture is
· determined by the duration or length of time that the
injectors are held open.
The Motronic control unit triggers the fuel injectors
sequentially in the firing order of the engine . Each
injector is triggered 360° before the ignition firing
point.
Solenoid winding
2 crankshaft revolutions
720°
Cylinder firing order
Cylinder injection sequence
SSP111/28
SSP111/27
The housing contains the solenoid winding and the
guide for the needle jet. When a ground is supplied
to the solenoid winding, the needle jet is pulled
away from the seat and the pressurized fuel exits the
injector .
~.-----------------------------------------------
...
- ---------
-------------------------
-------
-----
··
~..~.
11
Fuel Tank Ventilation System
----------------------------------------------
Fuel Tank Ventilation System ,
-
Fuel Tank Ventilation System
Fue l vapors that are formed in the fuel tank are
drawn into the engine for combustion via the carbon
canis ter.
When driving, fuel vapors are drawn into the intake
manifold from the fuel tank via the carbon canister
and then the frequency valve.
Throttle valve
The carbon canister is located on the right side of
the vehicle in front of the "~" pillar.
Intake manifold
·From tank
Depending on engine load and the oxygen sensor
signal, the frequency valve will regulate the
quantity of vapors entering the intake manifold.
In this way, an excessively rich fuel mixture is
avoided.
A spring -loaded check valve within the frequency
valve closes when the engine is off. This keeps the
fuel vapo r s from entering the intake manifold and
causing a rich mixture on a restart.
If powe r to the frequency valve is interrupted or lost
From control un it
when the engine is running, vacuum from the intake
manifold will open the check valve and allow a
calibrated amount of vapors to enter the intake
manifold.
Carbon canister
Carbon canister frequency ----t
valve
SSP111/29
The duty cycle for the carbon canister frequency
valve can range from 0-100% depending on engine
load. Below is an example of a 40% duty cycle.
Fuel
tank
U[V]
12
-
'
Open
0
-
Open
Open
C arbon canister
I -o
"O
"O
1a
0
u
~
Q
-
~
-
60%
40%
Ventilation
~
Q
-
Time[ms]
I
160ms
.,~
'.------------------------------------------------
SSP111/30
- ----------------------------------------------.i
..
Boost Pressure Control
~ ,,,:,,,.
---------------------------------------------The purpose of the boost pressure control system is
to ensure optimum boost pressure conditions
throughout the entire operating range of the engine.
-:- - --------------
not eliminates, "turbo lag." On other systems,
maximum boost pressure is not reached until the
engine speed is greater.
At full throttle, the boost pressure reaches a
maximum of 1.83 bar at 1,.950rpm. This reduces, if
-------------------------------
Four components are used to regulate boost
pressure : a bypass valve, wastegate, wastegate
frequency valve and the Motronic control unit.
Boost pressure
From engine
Boost Pressure Control
Control unit
Wastegate
0
0
0
0
0
The bypass valve is used to reduce boost pressure
in the intake air duct when the throttle plate is
closed, such as, at idle or when decelerating.
The use of the bypass valve serves another function,
which is to maintain a higher speed of the turbo
with the throttle closed. This improves the
response characteristics of the turbocharger when
accelerating.
cont rol
0
"'
0
0
Duty cycle
0-100%
From air filter
To catalytic converter
Turbine
Compressor
Bypass vahe
Throttle valve
SSP111/32
I
'l ,i...._
',~
____________________________________________
To __;;;,_engin e
-
-------
------------
---------------
-----
-----
-_;
··
Boost Pressure Control
~.,'-----------
-----------------------------------
Idling Stabilization
-
Wastegate Frequency Valve
Idle Stabilizer
The wastegate frequency valve control s boost
pressure by controlling the wastegate.
the control unit determines the appropriate duty
cycle for the frequency valve .
The Motronic control unit senses intake manifold
pressure by a pressure sensor inside the control unit.
Based on the amount of intaj<.emanifold pressure,
Depending on the duty cycle, the frequency valve
will regulate the amount of intake manifold boost
pressure to the wastegate to control boost pressure.
The idle speed is controlled by ignition timing and
an idle stabilizer. The ignition timing is used to
quickly adjust the idle speed during load change s.
The idle stabilizer is used to maintain the corrected
air volume .
The idle stabilizer is a single winding rotary-type.
When current is supplied to the valve , the rotary
valve will rotate against spring pre ssure to the
desired opening. The opening is determined by the
Motronic control unit.
Wastegate frequency valv e
From engine
Control unit
To intake manifold
To intake manifold
From throttle valve
potentio meter
Rota ry slide valve
To pressure se nsor
To catal ytic converter
To engin e
J II
¢
From
air
filter
From air filter
I,
\J
SSP111 /33
SSP111/35
Bypass Valve For The Turbocharger
The bypass valve is operated by intake manifold
vacuum. During idle or deceleration with the
throttle valve closed , the bypass valve is opened by
vacuum against spring pressure.
" Normal function "
When the valve is open, intake air is recirculated
and the turbo is free to spin but doesn't develop any
boost pressure. This maintains a higher speed of the
turbo and improves the response of the turbo.
From air filter
Bypass valve
Throttle vah·c
T o l·nginc
·i:i.....------- -----
"E mergen cy running" and "engine off' '
If the current to the valve is interrupted or lost, the
rotary valve is forced back by spring pressure to a
stop. This fixed position correspond s to a warm
engine idle speed.
From engine
To catal ytic
con verter
From air
filter
---------------
SSP111 /34
-------
-----------
-
..
Knock Control
\,,"--------------------------------------
Connector Assignments
---- --
Knock Contro l
Engine knock indicates increased thermal and
mechanical load of the engine. When an engine
starts to knock is determined by compression ratio,
fuel mixture, fuel quality and engine temperature.
The knock sensor system for the 20-Valve turbo
uses two knock sensors. The use of two knock
sensors allows the system to detec t the slightest
knocking noise and which cylinder caused the
knock.
I 1 I 2 I 3 I4 I s I 6 I 1 I a I s
System response to knock:
The ignition timing is retarded in 3° increments
System response to continued knock after timing
retard:
The fuel mixture is enriched to reduce the
combustion temperature which reduces knock
System response to continued knock after timing
retard and fuel mixture enrichment:
-
Boost pressure is reduced to a predetermined
level to decrease knock
When the knocking has been eliminated, the
ignition timing is returned to its normal value in
1.3° increments and boost pressure is returned to its
normal value .
·~'------
---
------------------------
l
Knock sensor
Basic design of the knock sensor system:
-
I I
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55
The Motronic control unit will then retard the
ignition timing for that cylinder, depending on
engine temperatu re and boost pressure.
-
I
110111 112 13 114 I15 16 11 f 1s f 1s
SSP111/36
Pin
Assignment
Pin
Assignment
1
2
3
4
5
6
7
8
9
10
11
12
Output stage for ignition coil
Coding plug
Fuel pump relay
Idle stabilizer
Carbon canister frequency valve
Tachometer/trip computer
Air mass sensor
Hall sender (signal wire)
Open
Ground
Knock sensor I
Hall sender, altitude sensor, throttle valve
potentiometer and coding plug (+)
Diagnostic plug connector (L wire)
Control unit ground
Injector #3 (-)
Injector #2 (-)
Injector #1 (-)
Terminal #30 (+)
Control unit ground
Open
Open
Diagnostic plug connector (output)
Wastegate frequency valve(-)
Control unit ground
Air mass sensor (+Pin 4)
Air mass sensor (+Pin 2)
Terminal #15
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
Oxygen sensor (signal wire)
Knock sensor II
Ground
Boost pressure indicator for trip computer
Trip computer
Open
Injector #5 (-)
Injector #4 (-)
Multi-function switch (Pin R)
Voltage output
Coding plug
Coding plug
A/C compressor
Idle speed increase signal (A/C On)
Open
Open
Intake air temperature sensor
Coolant temperature sensor
Altitude sensor
Engine speed sensor
Ground for data sending units
Reference sensor
Open
Open
Idle switch
Throttle valve potentiom eter
Coding plug
Diagnostic plug connector (K wire)
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
- -------------------------------------------
\..
Power Supply
1.---------
----------------
Grounds
--------------------Ground Connections
Ground connections for the Motronic Engine
Management System are located on the engine
block next to the ignition distributor.
The fuses below are for the Motronic Engine
Management System.
No.
Rating
Description
Connection
S13
15 A
Fuel pump
Fuel pump
S24
lOA
Engine control
Wastegate frequency
valve, idle stabilizer,
carbon canister
frequency valve
S27
5A
Engine control (Motronic)
Running in
emergency mode
(limp-home)
Off
Off
15 A
Engine control (Motronic)
Injectors, air mass
sensor
S29
lOA
Oxygen sensor heating
element
Oxygen sensor
heating element
One ground is used for the sensors, control unit and
the shielding of the sensor wires. The ground wire
for these components is 1.5 mm in diameter.
Off
Terminal #30 for
control unit
S28
Color codes for fuses:
5 Amp: Beige
10 Amp: Red
15 Amp: Blue
Engine condition
when fuse is
defect ive
1.5 mm ground
4.0 mm ground
Runs
Fuel pump relay
The second ground connection is used for the output
stage actuators (fuel injectors, etc.) and a seco nd
ground for the control unit. The diameter of this
ground wire is 4.0 mm .
',\'.,_
..1
___
____
..
___________________________________________
_ ______________________________
r
'~ ~
Wiring Diagram
------------~--~--------------------~
30
·~~
-~-----------+---...;;,---------------------~
·--+~~~+-r-----~~~~~xm
·~~ --+--------------+-----+--------------------~
~
B15
~
COIL
1/ 15
31
~
OUT
IN
ltJ5A
Legend
F 60 Idle switch
F 96 Altitude sensor
OUTPUTS
INPUTS
fi1s27
G4
G6
G 28
G 39
G 40
G 42
G 61
G 62
G 66
G 69
G 70
4N
DIAGNOSTIC CONNECTORS
I
IGNITION
DISTRIBUTOR
2
22
©
Color coding
Green = Input signal
Blue
= Output signal
Red
= Power supply
Brown = Ground
M30ac
I
POWER
STAGE
IGNITION
15
r.\
42
r.\
3
4
5
6
43
J 17 Fuel pump relay
J 220 Motronic control unit
J220
8
N 30
N 31
N32
N33
N 83
N70
N71
N75
N 80
~33
/WAKE
AIR
TEMP
SENSOR
T6 m
11-
61
KNOCK
SENSOR II
K
RI
G4o
F96
HALL
SENDER
THROTTLE
VALVE
POTENTIOMETER
IDLE
SWITCH
CODING CONNECTOR
ALTITUDE
SENSOR
_ ,______...._________________________________
___
-
... ______
~
..... -H-------tt-
....
--------H---9
2,5
2 ,5
6
·---------=------------------------------4.0
'.l
24
25
') t,
?7
Ignition reference sensor
Fuel pump
Engine speed sensor
Heated oxygen sensor
Hall sender
Intake air temperature sensor
Knock sensor I
Coolant temperature sensor
Knock sensor II
Throttle valve potentiometer
Hot wire (air mass sensor)
')S,
?Q
~"
~1
1?
11
14
35
SSP111/40
36
37-
38
39
40
41
42
43
44
45
46
47
48
49
Fuel injector, cyl. #1
Fuel injector, cyl. #2
Fuel injector, cyl. #3
Fuel injector, cyl. #4
Fuel injector, cyl. #5
Power stage (ignition coil)
Idle stabilizer valve
Wastegate frequency valve
Carbon canister frequency valve
P
Q
Spark plug connectors
Spark plugs
S 13
S 24
S 27
S 28
S 29
Fuse , fuel pump
Fuse , engine electronics
Fuse, engine control (Motronic)
Fuse, engine control (Motronic)
Fu se, ,heating element for oxygen sensor
T 6m Coding connector
Z 19
Heating element for oxygen sensor
137
138
Ground connection at engine block
Ground connection at engine block
Wiring Diagram
---- - ------------------------------------------------·-,
Wiring Diagram
~'1-------------------------------------------------
I LI
'h-c
r f.,
30
15
X
31
~
~
s
5A
13~
.
,;,
H87F
1
BS
I
®.S29
15A
10A
rn. ..
rn. ,,
m . ,,
I
I 17
\:I
16
m . .,
CYL ..
I 15
I 34
I 35
,~:
, ,B1s
' '1 115
N10
~
L
I
111
I
-
©
->-
4N
l
1
I
POWER
STAGE
IGNITION
COIL
CARBON
CANISTER
FREQUENCY
VALVE
10A
~ ~~~~~,
il~ ~ ~
DIAGNOSTIC CONNECTORS
•••mo•
DISTRIBUTOR
$$
I
!1 ii ii ti 'p
fa
.
14
3
·1 5
'2 1
©
'
11
28
,
1
1
10
, ,37,
25
/,
1
-
A
'""
26 Jso
\:I
I s1
\:I
I
,49
1
48
'
47
1
19
11
~,.SS
L
y
'1
r.\
r.\
22 '42 ,43 ' '36
18
'"
,--
'
I
~
1'6
~
Z19 ,
l' s
'I\
'1\
1'2
©
I
G39
OXYGEN
SENSOR
I
30
, s2
1
,29
1 153
G28
G4
AIR MASS SENSOR
REFERENCE
SENSOR
G61
I
G66
II
KNOCK
SENSOR I
ENGINE SPEED
SENSOR
I
12
'
1
'
I
8
16
6
7
8
9
10
I
\3
~IS
,4 Q59l5
F6o
y
'31
1
32
,54
pa,,39
1
I
6
'i'20'i'21
46
,24
J,33
I 12
1
,14
I
12
13
14
15
16
17
18
19
20
21
1
~
3/ +
I
q1"~'
,11- G40
THROTTLE
VALVE
POTENTIOMETER
F96
SENDER
1'6~5
,~
j
l\3
'12
1'1
I
T6m
CODING CONNECTOR
ALTITUDE
SENSOR
2,5
e
11
1 I
,-©
',-~
1L
Ft>
KNOCK
SENSOR II
I
'2
I
1.5
@
,@
5
1
INTAKE
AIR
TEMP
SENSOR
IDLE
SWITCH
4
1
41
I
@)
3
.144
[gjj ~~
''1 [ill
G10
1,5
2
'40
'
[l ( =~
--::Il jf ---- .,
--
(
111213' 1415161
J220
n n
-a [a'
COOLANT
TEMP.
SENSOR
- - ..
-
J 45
OUT
,,
2
' ;i-'
OUTPUTS
IN
~S21 5A
~~·~
I 23
,M30ac
INPUTS
~
~
'Q7
I
JLA
-l l'
I
l
.Lt\
..
IDLE
STABILJZATION
VALVE
S2a~
S24
~
WASTEGATE
FREQUENCY
VALVE
X
31
J71\ f91LA
~ 2/87, ~9 \
7a
0
15
FUEL
PUMP
RELAY
J17
~v
T
•
I 50131
I 45
48/ 30
30
-
22
(0
4 ,0
23
24
25
26
27
28
2,5
29
30
ss P111/40
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
Self-Diagnosis
Self-Diagnosis
The self-diagnosis system for the Motronic Engine
Management System monitors signals transmitted
by sensors and actuators. If faults occur, they are
stored in a permanent memory in the control unit.
1 = Power supply
Faults that occur sporadically (intermittently) or
faults that are not erased after they have been
repaired are displayed as "sporadic faults." These
types of faults are cleared by the control unit if the
fault does not recur after the next 10 engine starts .
2
3
= K - / L - lead
= Flash
code output connection
l),H,G - EIGnmrnGNff,E
1 - 5,:,hne11e [:iateni..iber-tra~9
HELP
aaa G
•••
8
aaa EJ
The permanent memory can only be erased by
disconnecting the control unit plug, disconnecting
the battery or by using the V. A. G 1551.
3
V.AG 1551
[email protected]
2
Diagnostic Connectors
The diagnostic connectors are located in the
footwell on the driver's side, next to the pedals.
The diagnostic connectors consist of three plug
connectors.
The possibility of incorrect connection is eliminated
by different housing designs.
SSP111/42
SSP111/41
1 = Voltage supply
2 = Fast data transfer
3 = Flash code
·:,\
-------------------------------------------
-
After connecting the 1551, the appropriate addre ss
word needs to be selected.
When engine electronics is selected, the following
functions can be called:
01 - Engine electronics
01 - Check control unit ver sion
02 - Check fault memory
03 - Output check diagno sis
04 - Introduction of basic setting s
05 - Erase fault memory
06 - End output
Self-Diagnosis
't
In order to bring training information to in-dea lership personnel, Service Training
develops and issues Self-Study booklets. The book lets describe and explain
new product changes, and system and component operation. These booklets are
produced on an as-needed basis as product changes and developments take place.
If the function, "04, Introduction of Basic Setting"
is selected, the following values should appear in
the display:
System in basic setting:
200
25
8p
100
128
130
48
lr8
128
36
l
. I
E ngme speed
Set value 77 ... 83
(corresponds to
770 ... 830 rpm)
Lambda control
Set value 123 ... 133
(corresponds to 0.5 ...
0.9 vol.% should be
set after 90 s)
Ignition firing point
Set value 35 ... 37
(corresponds to 8 ... 12° before TDC)
Engine temperature
Set value 184 ... 215
(corresponds to 85 ... 105 °C)
The actual values can be checked and compar ed
with the set values. If the actual values dev iate
from the set values, refer to the Repair Manual
Microfiche for further troubleshooting information.
Output Check Diagnosis
Actuator diagnosis is provided through the use of
the 1551 to provide a quick check of the wiring and
mechanical operation of certain components.
When this function is selected,
operate the components below
a pulsed voltage. For complete
procedures, consult the Repair
the control unit will
one after another by
output diagnosis
Manual Microfiche.
Fuel injector, cylinder #1
Fuel injector, cylinder #2
Fuel injector , cylinder #4
Fuel injector, cylinder #5
Fuel injector, cylinder #3
Idle stabilizer valve
Carbon canister frequency valve
Wastegate frequency valve
(N 30)
(N 31)
(N 33)
(N 83)
(N 32)
(N 71)
(N 80)
(N 75)
The actuators are checked acoustically (clicking
noise). The clicking noise does not guarantee
absolute function of the component during engine
operation. Additional testing may prove necessary .
Five booklets are normally shipped to all Audi dealers participating in the
Automatic Supply Program. In order to make it possible for extra copies to be
obtained if needed , additional booklets may be ordered via normal ordering
procedures . The booklets will then be shipped directly to the ordering dealer
and the parts account billed accordingly.
The following book lets are available and can be ordered:
Book Title
Part#
Price
CIS-Electronic
Fuel Injection
WSP-521-142-00
$9.00
CIS-E III Engine
Management System
WSP-521 - 146-00
$7.50
Digital Climate Control
(up to 1988 M.Y.)
WSP-521-137-00
$6.50
Audi Coupe Electronic
Instrument Display
WSP-521 - 138-00
$6 .50
The New Audi 80
and Audi 90
WSP-521-151-00
$12.50
The New Audi 100
and Audi 200
WSP-521-170-00
$ 10.00
1989 Model Change
Information
WSP-521-180 -00
$10 .00
Audi Coupe Quattro
with 20-Valve Engine
WSP-521-200-00
$10.00
The New Audi V8
Quattro
WSP-521-201-00
$12.00
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