Bosch Cis-E Iii System Audi 5000 S Quattro

DESCRIPTION

The CIS-E III system uses 2 interfacing computers. The Ignition Control Unit (ICU) on 5000S or Knock Sensor Control Unit (KSCU) on Coupe GT controls ignition. The Fuel Injection Control Unit (FICU) on 5000S or Ignition Injection Control Unit (IICU) on Coupe GT controls fuel injection. The system also has self diagnosis and trouble shooting capabilities.

Input and output signals from various sensors, switches and signalling devices are constantly monitored for faults. These faults are stored in memory. Faults can be displayed by a flashing 4-digit code sequence from an LED light located on the instrument cluster.

Note. Operation, testing, removal and installation, and adjustment procedures pertain to the 5000S. Procedures for the Coupe GT are similar.

Air Sensor Potentiometer

The air sensor potentiometer generates a voltage signal based on the position of the airflow sensor plate. The FICU uses this signal to determine cold acceleration enrichment.

The ICU uses the information to measure the position of the plate. This measurement determines engine load. This value, along with engine speed, is used to control the ignition timing. The potentiometer is connected to the plate by the air sensor lever.

Altitude Sensor

Depending on altitude or barometric pressure, the altitude sensor sends a varying voltage signal to the FICU to correct the air fuel mixture. The ICU also uses this signal to determine proper ignition timing. The altitude sensor is attached to the ignition control unit mounting bracket behind the left kick panel. (Scheme 23)

CIS-E III Electronic Control System. Scheme 20

Knock Sensor

The knock sensor consists of a piezoelectric crystal encased in a metal and plastic housing. Vibrations in the engine cause the crystal to generate small amounts of voltage. This voltage signal is used by the ICU to determine necessary timing retardation.

If knocking is detected, the ICU will retard the ignition 3.4 degrees. If the knocking stops, timing will advance in steps of .54 degrees until it reaches the pre-programmed value. If knocking continues, timing can be retarded as much as 12 degrees.

The knock sensor is located on the left side of the cylinder block, next to cylinder No. 3. The knock sensor connector is located on a bracket next to the distributor.

Oxygen Sensor

The Oxygen (O2) sensor is a heated type sensor that measures the oxygen content of the exhaust gases. The FICU uses the data from the O2 sensor to determine the air fuel mixture.

On vehicles with manual transmission, the O2 sensor is located on the exhaust pipe just ahead of the catalytic converter. On vehicles with manual transmission, the O2 sensor is located at the front of the catalytic converter. The connections for the O2 sensor and it's heating element are located on a bracket next to the distributor.

Temperature Sensor

The temperature sensor consists of 2 thermally variable resistors. One of the resistors signals the temperature of the coolant to the ICU. The other resistor signals the same information to the FICU.

These signals are used to provide corrections to the air fuel mixture, depending on coolant temperature. Both resistors have the same resistance value. The temperature sensor is located in the cylinder head coolant outlet flange.

Throttle Switches

The idle switch and full throttle switch provide throttle position data to both the FICU and the ICU. Throttle switches are located on the throttle body. (Scheme 21)

The idle switch is closed when the throttle plates are closed and opens when the throttle opens approximately one degree. The idle switch signal determines the operation of the stabilizer valve, deceleration fuel shutoff and activation of a special ignition timing map.

The full throttle switch closes at about 10 degrees before full throttle. The full throttle switch signal determines full throttle enrichment and the activation of a special timing map for full engine load.

The ICU and FICU also use data from the throttle switches to check the operation of the air sensor potentiometer.

Location of Throttle Switches. Scheme 21

CANISTER SHUTOFF SOLENOID

The shutoff solenoid valve is de-energized when the engine is turned off. This closes the purge line between the carbon canister and the intake air boot, preventing fuel vapors, that may cause a hot start problem, from collecting in the intake tract.

When the engine is started, the canister shutoff solenoid is energized, allowing stored vapors to be purged from the canister. The canister shutoff solenoid is located on top of the carbon canister.

CONTROL UNITS

The Ignition Control Unit (ICU) collects signals from the altitude sensor, ignition distributor, knock sensor, temperature sensor, throttle valve switches and the fuel injection control unit. Using the collected data, it continuously updates the required degree of ignition advance/retard.

There are 2 separate ignition timing maps programmed into the ICU. One is programmed for regular fuel. The other is programmed for premium fuel.

When the coolant temperature reaches 149°F (65°C), the ICU automatically switches to the premium fuel map. The premium fuel map is programmed to have timing with a slightly advanced curve in some of the lower RPM ranges.

If ignition knock occurs repeatedly, the ICU will automatically switch to the regular fuel map. The ICU will switch back to the premium fuel map after a fixed amount of time or whenever the engine is restarted.

The Fuel Injection Control Unit (FICU) receives signals from the air sensor potentiometer, altitude sensor, oxygen sensor, temperature sensor, throttle valve switches and the ignition control unit. Using this data, it varies the air fuel mixture as necessary.

Both control units constantly interface with each other. Each control unit contains it's own fault memory. During self-diagnosis the ignition control unit will always display it's fault codes first. The fuel injection control unit will then display it's fault codes.

The FICU is in a slide-in bracket located behind the right kick panel. (Scheme 22) The ICU is bolted to a bracket located behind the left kick panel. (Scheme 23)

FAULT MEMORY

Both the FICU and ICU store faults for self-diagnosis. If a fault occurs, the computer memory will store a code and corrective action will take place. For example: the coolant temperature sensor develops an open circuit. In this case, both control units will assume a calculation value of a fully warmed engine.

The fault will be displayed by a flashing of the engine control indicator light. By inserting a fuse into the top of the fuel relay for 4 seconds, the diagnostic terminals will be grounded and the memories will be displayed by a flashing sequential code on the instrument cluster.

If the ignition system is operating in a fully retarded position because of engine knock or a problem has developed in the knock sensor system the indicator light will flash while driving.

Location of Fuel Injection Control Unit. Scheme 22

Location of Ignition Control Unit & Altitude Sensor. Scheme 23

Cold Start Valve

The cold start valve injects extra fuel into the intake manifold during cold starts. The valve is controlled by the FICU. The operation of the valve is determined by the coolant temperature to prevent excess fuel from being injected. The cold start valve is located on the back of the intake manifold.

Differential Pressure Regulator

The differential pressure regulator controls the fuel flow in the lower chamber of the fuel distributor. This helps to determine the fuel mixture.The regulator designates zero Milliamps (mA) as the reference point. The unit operates with current from the FICU that ranges between +10 mA (rich) to -10 mA (lean).

When the starter is operated, current to the differential pressure regulator is increased to enrich the fuel mixture. This will take place whenever the engine is started and the amount of increase will be regulated by coolant temperature. In extreme cold, current can be as high as 140 mA.

During cold acceleration, current can briefly raise to 6Ma to enrich fuel mixture. The enrichment is determined by engine speed and signals from the temperature sensor and temperature sensor.

During full load operation, the full throttle switch closes, sending a signal to the ICU. The ICU sends a signal approximately 3 mA greater than the signal that is currently present. This signal will vary, depending on engine speed and altitude.

When vehicle is decelerated, fuel to injectors is shut off by reversing current to -50 mA to -60 mA. The engine speed at which this reversing will take place is regulated by coolant temperature. Current will also be reversed if engine speed reaches 6600 RPM, acting as a governor. The differential pressure regulator is attached to the fuel distributor.

Operation of Differential Pressure Regulator. Scheme 24

Idle Stabilization Valve

The idle stabilization valve consists of a small single-wound motor, rotary valve and a return spring attached to the motor's armature. The valve controls idle speed. Varying amounts of DC voltage cause the motor to pull against the return spring.

The amount of current will determine how far the rotary valve is rotated. (Scheme 25) When the rotary valve is rotated, air from the intake air boot to the intake manifold by-pass varies.

The idle stabilization valve receives a voltage signal from the FICU. Variables that effect the amount of voltage received from the FICU are the engine speed, temperature sensor, idle switch, A/C compressor clutch and transmission gear position.

Idle speed is maintained between 650-790 RPM on warm engines and at about 1000 RPM for cold engines. With this system, no idle speed adjustments are necessary or possible. Idle stabilization valve is located between intake air boot and intake manifold.

View of Idle Stabilization Valve. Scheme 25

Ignition Coil

The ignition coil is equipped with a power stage mounted on the side. The power stage switches primary current in the coil on and off in place of the Hall control unit. The power stage acts like a solid state pair of ignition points and is controlled by signals from the ICU.

Ignition Distributor

The ignition distributor is a Hall Effect type with no centrifugal or vacuum advance. The Hall sender is operated by a 5-aperture trigger wheel. The voltage signal from the Hall sender is received by the ICU at approximately 60 degrees BTDC. The ICU uses this signal to determine engine speed and crankshaft position.

The ignition has an anti-tampering cover that is attached to a boss on the cylinder head next to the ignition distributor and covers the distributor clamp nut. To gain access to the clamp nut, the cover's shear bolt must be removed.

Note. Testing procedures pertain to the 5000S. Procedures for the Coupe GT are similar.

TESTING PRECAUTIONS

When testing the CIS-E III system, observe the following precautions to avoid injury or damage to the system.

1. DO NOT touch or disconnect ignition wires with engine running. Disconnect or connect engine wiring and test leads ONLY with engine off. DO NOT connect test lamp to terminal No. 1 of ignition coil.
2. If engine must be turned over but not started, remove coil wire from ground. Using a jumper wire, ground the coil wire. A fast charger can be used as a starting aid for no more than 15 seconds at a time with a one minute break between attempts and a maximum of 16.5 volts.
3. DO NOT use a standard ignition coil. Disconnect battery during any welding operations. When heating to more than 176°F (80°C), such as painting or steam cleaning, DO NOT start engine immediately.
4. Wash engine with engine not running and ignition off. DO NOT disconnect battery with engine running. DO NOT apply voltage to control units. DO NOT start engine with injectors removed.

1. Using Adapter (1315 A/1 ), connect multimeter to differential pressure regulator. Set multimeter to 200 mA DC scale. Turn ignition on. Insert fuse in top of fuel pump relay for at least 4 seconds.
2. Indicator light should display Code 4341. Multimeter should read 100 mA. Close full throttle switch. Multimeter reading should change to 10 mA.

CARBON CANISTER SHUTOFF SOLENOID

1. Turn ignition on. Insert fuse into fuel pump relay for at least 4 seconds. Indicator light should display Code 4343.
2. Close full throttle switch. Shutoff solenoid valve should energize, making a clicking sound when full throttle switch is closed.

Turn ignition on. Insert fuse into fuel pump relay for at least 4 seconds. Indicator light should display Code 4443. Close full throttle switch. cold start valve should click on and off for 10 seconds maximum.

IDLE STABILIZER VALVE

Turn ignition on. Insert fuse into fuel pump relay for at least 4 seconds. Indicator light should display Code 4431. Close full throttle switch. Idle stabilizer valve should cycle when switch is closed.

System Pressure

1. Remove fuel line from cold start valve. see scheme 7 Remove test plug from distributor lower chamber. Connect Pressure Gauge (VW 1318 ) between fuel line from cold start valve and lower chamber. see scheme 7
2. Disconnect differential pressure regulator connector from side of regulator. Remove fuel pump relay. Jumper fuel pump relay socket. Open valve on pressure gauge.
3. Energize fuel pump. Note pressure reading on pressure gauge. Pressure should be between. 88-94 psi (6.2-6.6 kg/cm 2 ). System pressure is not adjustable.

Differential Pressure Regulator Fuel Pressure

1. Connect Pressure Gauge (VW 1318 ) as previously described. see scheme 7 Close pressure gauge valve. Disconnect differential pressure regulator connector from side of regulator.
2. Operate fuel pump. Note reading on pressure gauge. Differential pressure should be 4.5-7.3 psi (.3-.5 kg/cm 2 ) less than readings noted in the FUEL INJECTION SYSTEM PRESSURE test.

Differential Pressure Regulator Electrical System

1. Connect Pressure Gauge (VW 1318 ) as previously described. see scheme 7 Close pressure gauge valve. Disconnect differential pressure regulator connector from side of regulator.
2. Using Adapter (1315 A/1 ), connect Multimeter (US 1119 ) to differential pressure regulator and to the connector removed from the regulator. (Scheme 26)
3. Set multimeter to 200Ma DC scale. Turn ignition on. Multimeter should read 100Ma. Pressure gauge should read 17-22 psi (1.2-1.5 kg/cm 2 ) less than readings noted in the FUEL INJECTION SYSTEM PRESSURE test.

Attaching Multimeter to Differential Pressure Regulator. Scheme 26

Residual Pressure

1. Connect Pressure Gauge (VW 1318 ) as previously described. see scheme 7 Open pressure gauge valve. Operate fuel pump for at least 30 seconds.
2. Shut off fuel pump. Note system pressure. Pressure should be 51 psi (3.6 kg/cm 2 ) after 10 minutes and 49 psi (3.4 kg/cm 2 ) after 20 minutes.

Note. The Residual Pressure Test does not include the cold start valve. To check cold start valve, reattach fuel line. Operate fuel pump. Visually check for leaks.

Cold Acceleration Enrichment

1. Disconnect differential pressure regulator connector from side of regulator. Using Adapter (1315 A/1 ), connect Multimeter (US 1119 ) to differential pressure regulator and to the connector removed from the regulator. NOTE: Coolant temperature must be below 104°F (40°C) to perform Cold Acceleration Test.
2. Set multimeter to 200Ma DC scale. Disconnect oxygen sensor connector. Start engine and let idle. Note multimeter reading. Accelerate engine. Multimeter reading should increase approximately 6Ma during acceleration.

Deceleration Fuel Shutoff

1. Warm engine to normal operating temperature. Disconnect differential pressure regulator connector from side of regulator.
2. Using Adapter (1315 A/1 ), connect Multimeter (US 1119 ) to differential pressure regulator and to the connector removed from the regulator. Set multimeter to 200Ma DC scale.
3. Accelerate engine to more than 3000 RPM. Release throttle, noting multimeter reading. Reading should decrease to approximately -50Ma with throttle closed until engine speed reaches about 1200 RPM.

1. Disconnect differential pressure regulator connector from side of regulator. Using Adapter (1315 A/1 ), connect Multimeter (US 1119 ) to differential pressure regulator and to the connector removed from the regulator.
2. Set multimeter to 200Ma DC scale. Disconnect oxygen sensor connector. Start engine and let idle. Note reading on multimeter. Ground male end of oxygen sensor connector.
3. Observe multimeter. Current should increase from 9Ma to 11Ma after 15 seconds. Reconnect oxygen sensor connector. Raise engine speed to approximately 3000 RPM for a few seconds.
4. Let engine idle. Current should fluctuate approximately 1-3Ma in the -10Ma to +10Ma range.

1. Drive vehicle for a minimum of 5 minutes to allow fault information to be stored. If it is a no-start condition, operate starter for at least 6 seconds. CAUTION: DO NOT turn ignition off. This will erase the fault memory. see scheme 9: Location of Fuel Pump Relay
2. Insert fuse into fuel pump relay for at least 4 seconds. see scheme 9 Indicator light on instrument cluster should display a 4-digit fault code from the ICU.
3. If indicator light displays a Code 4444, no faults have been recorded. Record all fault codes by repeating step 2) until a Code 0000 is displayed. This indicates that all fault codes from the ICU have been displayed.
4. Repeat step 2) after the Code 0000 is displayed. This time, however, the faults that are displayed will be from the FICU. Engine speed may increase. Record all codes.
5. Repeat step 2) until all FICU fault codes have been displayed. When all fault codes from the FICU have been displayed, a Code 0000 will display.
6. For a list of all ICU and FICU fault codes, refer to «SELF-DIAGNOSTIC FAULT CODES»(/audi/5000-s-quattro/1987-1988/remont/testing-diagnostics/#bosch-cis-e-iii-system) chart.

SELF-DIAGNOSTIC FAULT CODES

Version One Ignition Coil & Power Stage. Scheme 27

Version 2 Ignition Coil & Power Stage. Scheme 28

IGNITION COIL ASSEMBLY

Note. The CIS-E III system uses 2 versions of coils. Both versions use a power stage. DO NOT separately test the function of the power stage. (Scheme 27)and (Scheme 28) to determine which version you are testing.

Ignition Coil & Power Stage

1. On version one, disconnect ignition coil power stage connector. (Scheme 20) On version 2, Disconnect ignition coil power stage connector, Remove coil wire from ignition coil and remove screw from top of assembly.
2. On both versions, connect Multimeter (US 1119 ) between terminal No. 1 and ground. Connect multimeter between terminals No. 1 and No. 3. (Scheme 29) Turn ignition to "ON" position. Multimeter should read approximately 12 volts.
3. If not to specification, repair break in wiring. See «WIRING DIAGRAMS»(/audi/5000-s-quattro/1987-1988/remont/testing-diagnostics/#bosch-cis-e-iii-system). Connect multimeter between terminal No. 2 and No. 3.
4. Turn engine over with starter while reading the multimeter. Reading should be approximately 2 volts. If reading is within specification, check ignition coil.
5. If not to specification, check wiring between terminal No. 2 of connector and terminal No. 16 of the ICU. If wiring checks satisfactory, replace ICU.

Ignition Coil Connector (Versions One & 2). Scheme 29

Secondary Resistance

1. Check wiring between power stage and ignition coil and power stage ground wire for corrosion and damage. On version one, disconnect ignition coil power stage connector and ignition coil wire. (Scheme 27)
2. On version 2, disconnect ignition coil power stage connector and remove screw from top of assembly. (Scheme 28) On both versions, connect Multimeter (US 1119 ) between terminal No. 1 and coil wire socket.
3. Resistance should be between 5000-6000 ohms. If not to specification, replace ignition coil.

Primary Resistance

1. On version one, disconnect ignition coil power stage connector and ignition coil wire. (Scheme 27) On version 2, disconnect ignition coil power stage connector and remove screw from top of assembly. (Scheme 28)
2. Connect Multimeter (US 1119 ) between terminals No. 1 and No. 15. (Scheme 30)and (Scheme 31). Reading should be between.5-1.5 ohms. If not within specification, replace ignition coil.
3. If secondary and primary resistance values are within specification and there is still no ignition, replace ignition coil with power stage as an assembly.

Ignition Coil Terminal Location (Version One). Scheme 30

Ignition Coil Terminal Location (Version 2). Scheme 31

HALL SENDER

1. Disconnect coil wire from distributor cap. Using a jumper wire, ground the coil wire. Disconnect hall sender-to-ICU harness connector.
2. Connect multimeter between terminals No. 1 and No. 3 of connector "D". (Scheme 32) Turn ignition to "ON" position. Reading should be at least 9 volts. If not to specification, repair break in wiring. Turn ignition off.
3. If step 2) tests satisfactory, push back rubber boot on hall sender connector. Connect multimeter between terminals No. 1 and No. 2. Reconnect hall sender-to-ICU harness connector.
4. Turn ignition to "ON" position. Remove ignition distributor cap, rotor and dust cap. DO NOT allow spring clips to fall inward toward trigger wheel.
5. Using Wrench (2079 ), turn crankshaft until trigger wheel is clear of hall sender. Multimeter should read a minimum of 4 volts. Turn crankshaft until trigger window is aligned with hall sender.
6. Reading should be between.0-.5 volts. Turn ignition off. If reading was not to specification, replace hall sender. If reading was correct, check wiring between hall sender connector and ICU.
7. Remove ICU cover from left side kick panel. Disconnect harness connector from ICU and Connector "D" from distributor. Check for continuity between distributor connector pins and appropriate 25-pin ICU connector pins. For correct pin-to-pin reference (Scheme 32)and (Scheme 33) Also see «WIRING DIAGRAMS»(/audi/5000-s-quattro/1987-1988/remont/testing-diagnostics/#bosch-cis-e-iii-system).
8. If hall sender and wiring between connector "D" and the ICU connector tested satisfactory, replace ICU.

Scheme 32

Scheme 33

ADJUSTMENTS

Note. Adjustment procedures pertain to the 5000S. Procedures for the Coupe GT are similar.

Full Throttle Switch

The switch should close approximately 10 degrees before full throttle. The closed circuit signal is used for full throttle enrichment and activation of ignition timing circuit for full load engine operation. Adjustment is made by positioning on mounting bolts. (Scheme 21)

Idle Switch

The switch should be be in the closed position when the throttle is closed. The switch circuit should open when the throttle is opened approximately one degree. The switch completes the circuit when it is closed. It is adjusted by positioning with its mounting bolts. (Scheme 21)

SENSOR PLATE

To adjust sensor plate, refer to AIRFLOW SENSOR PLATE under ADJUSTMENTS in BOSCH CIS-E SYSTEM article in this section.

REMOVAL & INSTALLATION

Note. Removal and installation procedures pertain to the 5000S. Procedures for the Coupe GT are similar.

No procedures are available for removal and installation of CIS-E III related components. CIS-E III components are similar to those used in the CIS-E system. Refer to REMOVAL & INSTALLATION in BOSCH CIS-E SYSTEM article in this section.

Audi 5000 2.3L CIS-E III Wiring Diagram. Scheme 34

See also:
• BOSCH CIS-E SYSTEM
• SELF-DIAGNOSTIC FAULT CODES