Basic Testing Audi 200 C3 рестайлинг

INTRODUCTION

The following diagnostic steps are here to prevent overlooking a simple problem. This is also the place to start diagnosis for a "NO-START" condition.

The first step in diagnosing any driveability problem is to verify that the problem exists. This may be accomplished by test driving the vehicle under the conditions during which the problem reportedly occurs.

Prior to entering self-diagnostics, a careful and complete inspection of several systems is required. Most driveability or "no-start" problems are not related to computerized engine control systems, but are in fact simple mechanical, electrical, fuel or vacuum related faults. Most engine control problems are the result of mechanical breakdowns, poor electrical connections or damaged or misrouted vacuum hoses.

Before considering the computer system as a possible cause of problems, ignition high tension wires, fuel supply, electrical connections and vacuum hoses should be checked. Failure to do so may result in improper diagnosis or lost diagnostic time.

Note. All voltage tests should be performed with a Digital Volt Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless specifically stated different in testing procedures.

VISUAL INSPECTION

Perform a visual inspection of all electrical wiring. Look for chafed, stretched, cut or pinched wiring. Inspect electrical connectors and connections for tight fit and corrosion. Repair as necessary. Inspect all vacuum hoses for proper routing, cuts or pinches. If necessary, see VACUUM DIAGRAMS article to verify routing and connections. Repair as necessary. Inspect air induction system for possible vacuum leaks.

Compression

Engine mechanical condition can be checked using a compression gauge, vacuum gauge, or an engine analyzer capable of performing a relative compression test. See engine analyzer instruction manual for availability and description of relative compression feature.

Exhaust System Backpressure

The exhaust system can be checked with a vacuum gauge or a pressure gauge. Remove O2 sensor or air injection check valve, if equipped. Connect a 1-10 psi gauge and run engine at 2500 RPM. If exhaust system backpressure is greater than 1 3/4-2 psi, exhaust system or catalytic converter is plugged.

If a vacuum gauge is used, connect it to intake manifold vacuum. Observe vacuum gauge. Open throttle part way and hold steady. If vacuum gauge slowly drops after stabilizing, exhaust system should be checked for a restriction.

FUEL SYSTEM

FUEL PRESSURE (CIS DIGITAL CONTROL)

Note. For more information on fuel pressure specifcations, see FUEL SYSTEM in SPECIFICATIONS article.

Basic diagnosis of fuel system should begin with determining fuel system pressure.

System Pressure

1. Connect Pressure Gauge (VW 1318) between line from fuel distributor to cold start valve and test port connection on lower chamber of fuel distributor, using Adapter Fittings (VW 1318/5). Test port is sealed by a threaded plug. Bridge fuel pump relay (located on fuse/relay panel) with Jumper Switch (US 4480/3). NOTE: Fuel pump may also be activated by jumpering 12 volts to by-pass terminal on fuse/relay panel. See «WIRING DIAGRAMS - CEC»(/audi/200/c3-1988-1991/remont/wiring-diagrams-engine-performance/#wiring-diagrams-cec) article in this section.
2. Open valve on pressure gauge (points at cold start valve line when open) and activate fuel pump. System pressure must be 68-78 psi (4.7-5.4 kg/cm 2 ). If pressure reading is low and fuel pump delivery quantity is good, adjust or replace regulator assembly.
3. If pressure reading is high, disconnect fuel tank return line from fuel distributor. Repeat test. If reading is correct, check for plugged return line. If reading is incorrect with line open, replace regulator assembly.
4. If pressure is not within specification and regulator valve has been replaced, adjust system pressure at fuel distributor. See «ADJUSTMENTS»(/audi/200/c3-1988-1991/remont/adjustments/#adjustments) article in this section.

Residual Pressure & Internal Leak Testing

1. Open valve on pressure gauge. Operate fuel pump for 30 seconds. Pressure can drop to a minimum of 38 psi (2.7 kg/cm 2 ) after 10 minutes. If pressure drops below specification, inspect fuel pump check valve and all fuel fittings for leakage. NOTE: Pressure and leak testing does not include checking cold start valve.
2. If there are no leaks, check sensor plate clearance. If plate clearance is correct, replace regulator assembly and repeat leak test. If pressure drop is not within specification, replace fuel distributor "O" rings.

Main Pump Delivery Volume

1. Check transfer pump (if equipped) and fuel filter. Disconnect fuel return line and place open end in measuring container. Switch on fuel pump with jumper switch. Check fuel pump delivery volume for 30 second period.
2. Minimum delivery volume is .71 qts. (.68L) for 30 seconds with reading of 11.4 volts at fuel pump. Voltage is measured with engine off and fuel pump activated by jumper switch.

Scheme 1

1. Remove fuel pump relay, from relay panel, and install Jumper Switch (US 4480/3). Attach Fuel Quantity Analyzer (US 4480) to bumper and secure in place. Remove injectors from cylinder head with fuel lines attached. Check and replace fuel injector "O" rings as necessary.
2. Check tightness of injector insert (2-piece inserts). If inserts are loose, remove and clean threads. Use sealing compound when installing upper insert. Replace sealing washer against cylinder head below lower portion of insert. Lubricate injector "O" rings with gasoline and install injectors with fuel lines connected, into fuel quantity analyzer tubes.
3. Ensure lines are not kinked or bent. Loosen fittings to align fuel lines and retighten. Remove rubber boot from airflow sensor housing above sensor plate. Turn and lift setting screw and adjusting slide of Sensor Plate Adjustable Holder (VW 1348/1) into upper position. This simulates full throttle operation. (Scheme 1)
4. Place sensor plate adjustable holder on airflow sensor housing with holder centered over plate. Pointer on edge of holder base must point toward center of fuel distributor. (Scheme 1) Push adjusting slide of holder down onto stop.
5. Turn adjusting screw clockwise until magnetic end touches sensor plate retaining bolt. Activate fuel pump with jumper switch. Turn adjusting screw of holder counterclockwise until any one injector starts to deliver fuel. Turn off jumper switch and empty fuel quantity analyzer into fuel tank.
6. Idle injection quantity is measured first. Lifting adjusting slide of holder to first stop simulates idle position of sensor plate. Activate fuel pump with jumper switch until fuel level reaches 20 ml on scale of any tube for quantity comparison. NOTE: The abbreviation "ml" stands for milliliters.
7. Check that all injectors have identical spray patterns that are even and cone-shaped. If not, raise sensor plate up quickly to full lift position and release. Repeat idle quantity test. Maximum difference in delivery quantity between injectors is 3.0 ml of fuel.
8. If fuel delivery quantity differs between high and low levels by more than 3.0 ml, interchange injectors and repeat test. If difference of delivery quantity changes with injectors, replace injectors. If difference of delivery quantity does not change with movement of injectors, either fuel lines are pinched or fuel distributor is defective.
9. Measure full throttle injection quantity. Empty analyzer into fuel tank and reinstall injectors in analyzer. Lift adjusting slide of holder to last stop to simulate full throttle position of sensor plate. Activate fuel pump with jumper switch until fuel level reaches 80 ml on scale of any tube of analyzer.
10. Check that all injectors have identical spray patterns that are even and cone-shaped. Maximum difference in delivery quantity between injectors is 8.0 ml of fuel.
11. If fuel delivery quantity differs between high and low levels by more than 8.0 ml, interchange injectors and repeat test. If difference of delivery quantity changes with injectors, replace injectors. If difference of delivery quantity does not change with movement of injectors, either fuel lines are pinched or fuel distributor is defective.
12. Check fuel injectors for leakage immediately after delivery quantity test is complete. Set sensor plate in rest position. Activate fuel pump with jumper switch for 2 minutes. Injectors should not drip. Replace injectors that do drip.

Fuel Pump Relay

1. Remove fuel pump relay from relay board. Turn ignition on. Test light should light when connected between socket for relay terminal No. 46 and ground. (Scheme 2)
2. While starter motor is operating, test light should flicker when connected between sockets for relay terminals No. 50 and 51. Test light should light when connected between sockets for relay terminals No. 46 and 50. Test light should light when connected between sockets for relay terminals No. 46 and 52.
3. If test light does not light up for all tests, check wiring for continuity. If test light does light up for all tests but there is no voltage at fuel pump with relay installed, replace fuel pump relay.

Scheme 2

FUEL PRESSURE (CIS-E III)

Note. For more information on fuel pressure specifcations, see FUEL SYSTEM in SPECIFICATIONS article.

1. Remove fuel line from cold start valve. (Scheme 3) Remove test plug from distributor lower chamber. Connect Pressure Gauge (VW 1318) between fuel line from cold start valve and lower chamber. (Scheme 3)
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 88-94 psi (6.2-6.6 kg/cm 2 ). System pressure is not adjustable.

Residual Pressure

1. Connect Pressure Gauge (VW 1318) as previously described. (Scheme 3) 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. Residual Pressure Test does not include cold start valve. To check cold start valve, reattach fuel line. Operate fuel pump. Visually check for leaks.

Fuel Pump Relay Control

1. With ignition off. Remove fuel pump relay from relay panel. Connect multimeter between terminals No. 48 and No. 50 of relay socket. (Scheme 4)
2. Multimeter should read 12 volts. Connect multimeter between terminals No. 46 and No. 50 of relay socket. Turn ignition on. Multimeter should read 12 volts.
3. If multimeter does not read as specified, repair break in wiring. Connect multimeter between terminals No. 46 and No. 47 of relay socket. Momentarily engage starter. Multimeter should read 7 volts.
4. If multimeter does not read 7 volts, partially remove ICU and disconnect harness connector. Using a multimeter, check continuity between ICU and relay socket.
5. Connect terminal No. 3 of ICU connector to terminal No. 49 of relay socket. Connect terminal No. 14 of ICU and terminal No. 47 of relay socket. Multimeter should read.2 ohm.
6. If reading is not as specified, repair break in wiring. If reading is as specified, replace knock sensor.

Scheme 3

FUEL PRESSURE (CIS MOTRONIC))

Note. For more information on fuel pressure specifcations, see FUEL SYSTEM in SPECIFICATIONS article.

Scheme 4

1. Ensure engine is at normal operating temperature. Connect Fuel Pressure Tester (VW1318) to measuring location No. 1 on fuel distributor using Adapter (VW1318/4). Close fuel pressure valve. (Scheme 5)
2. Remove fuel pump relay from fuse panel and connect Remote Control (US4480/3) in fuse panel fuel pump relay cavity. Ensure fuse No. 13 on fuse panel is good.
3. Open valve on pressure tester and energize fuel pump with remote control. Fuel pressure should be 89-94 psi. (6.3-6.6 kg/cm 2 ). If fuel pressure is too high, carefully remove fuel return line from fuel pressure regulator and place in container.
4. Repeat test in step 2). If fuel pressure is still too high, replace fuel pressure regulator. If pressure is okay, check return line for obstruction or kinks. Repair or replace as necessary.

1. This procedure is only required for hot start problems. Turn valve open on fuel pressure tester. Energize fuel pump for 5 seconds using remote control. Note fuel pressure drop over time. Fuel pressure should not drop more than 2 psi in 10 minutes.
2. If fuel pressure drop is greater than 2 psi in 10 minutes, check fuel pump check valve, airflow sensor plate free play and sealing rings on fuel distributor and fuel lines.

ECU Voltage Supply

1. Unplug ECU harness connector. Connect voltmeter positive test lead to pin No. 35. (Scheme 6) With ignition switch on, voltmeter should indicate 12 volts with negative test lead touching either No. 18 and No. 9. If not, repair ignition circuit 15 or battery to ignition switch.
2. Turn ignition switch off. Connect positive voltmeter lead to terminal No. 32 and negative lead to No. 9. With ignition switch on, ensure 12 volts are present when brake pedal is depressed. If not, check wiring for open or check brake light switch. Turn ignition switch off. Reconnect ECU harness connector.

Engine Speed Sensors

1. Remove Gray (engine RPM) and Black (ignition timing reference) connectors from bracket near ignition coil. Connect ohmmeter to each sensor connector terminals No. 1 and 2. (Scheme 7) Ohmmeter reading should be 1000 ohms.
2. If not, replace sensor(s). If reading is correct, check continuity between each sensor connector terminals No. 1 and 3, and 2 and 3. If ohmmeter reading is not infinity (4), replace sensor(s).
3. Unplug connector from ECU. Check wiring between harness side of each sensor connector and ECU. (Scheme 6)and (Scheme 7). Ensure each wire between ECU and sensor connectors has zero ohms of resistance. See «ENGINE SPEED SENSOR CIRCUITS»(/audi/200/c3-1988-1991/remont/testing-diagnostics/#basic-testing) chart. ENGINE SPEED SENSOR CIRCUITS Sensor Terminal Connector Terminal Engine RPM (Gray) 1 29 2 11 3 28 Ignition Timing Reference (Black) 1 13 2 12 3 28
4. Ensure clearance between ignition timing reference sensor and flywheel pin is.43" (1.10 mm) If engine speed sensors and wiring circuits are okay, replace control unit.

Scheme 5

Scheme 6

Hall Effect Sending Unit

1. Remove protective cover from Hall Effect sending unit (on distributor) and unplug connector from unit. Connect voltmeter to connector terminals No. 1 and 3. Turn ignition on. Voltmeter reading should be 9 volts minimum.
2. If reading is incorrect, check for open circuit in wiring between ECU terminals No. 23 and 25, and sending unit. If reading is correct, turn ignition off. Move back connector cover to gain access to rear of 3-wire connector. Reinstall connector to distributor Hall sending unit. Connect voltmeter between terminals No. 1 and 2 at rear of connector.
3. Remove distributor cap, rotor, and dust cover. Turn crankshaft by hand until rotor window clears sending unit. Turn ignition on. Voltmeter should indicate 4 volts minimum.
4. Turn crankshaft until rotor window fully aligns with sending unit. Voltmeter should indicate 0-.5 volts. Turn ignition off. If readings are incorrect, replace Hall sending unit. If readings are correct, check wiring between Hall Effect sending unit and ECU for shorts or opens in wires.
5. Repair wires if necessary. If circuits are okay, replace ECU.

Knock Sensor

If engine knocking is present, knock sensor will produce a small voltage of about 50-70 milivolts. If engine knocking continues, check fuel quality, compression pressure, knock sensor and wiring circuits. No other tests are available from the manufacturer.

Spark Plug Wires & Rotor

1. Check coil wire resistance. If radio suppression wires are used, coil wire resistance reading should be 1200-2800 ohms. If not, resistance reading should be zero ohms.
2. Check resistance of spark plug wires. If radio suppression wires are used, spark plug wire reading should be 4600-7400 ohms. If not, spark plug wire reading should be 600-1400 ohms. Check spark plug connectors. If radio suppression connectors are used, reading should be 4000-6000 ohms. If not, connector reading should be 600-1400 ohms.
3. Check rotor and spark plug wire distributor cap connectors. Resistance of each connector should be 600-1400 ohms. Ensure rotor is marked "R1".

Ignition Coil Resistance Check

Using ohmmeter, check ignition coil primary and secondary resistance. Disconnect coil primary and secondary ignition leads. Connect ohmmeter leads across primary terminals No. 1 and 15 at coil. (Scheme 8) Resistance value should be.5-1.5 ohms. Connect ohmmeter leads between positive terminal (No. 1) and coil high voltage tower. (Scheme 9) Secondary resistance value should be 5000-9000 ohms. If resistance values are not to specification, replace ignition coil.

Scheme 7

Scheme 8

1. Check Blue wire from terminal No. 1 of ignition coil to power transistor for any damage. Repair if necessary. Remove secondary ignition wire from coil tower. Using a jumper wire, connect coil tower wire to ground.
2. Disconnect power transistor connector (next to ignition coil). Connect voltmeter between terminal No. 1 (Green/White wire) and ground. (Scheme 8) Install a jumper wire between terminal No. 2 (Brown/White) and ground. NOTE: Ensure test lead connections are correct. If reversed, ECU will be damaged.
3. Crank engine. Ensure voltmeter reading is.20 volts minimum. If reading is incorrect, check wiring between switching module and control unit connector as follows.
4. Unplug ECU connector. Using an ohmmeter, check continuity between terminal No. 2 of ECU connector and terminal No. 2 of power transistor connector.
5. Also check continuity between ECU connector terminal No. 22 and terminal No. 1 of power transistor connector. (Scheme 6) Ohmmeter reading should be close to zero ohms for both tests. If not, check for open circuit between ignition control unit and switching module. If wiring is okay, replace ECU.

Tachometer Signal Output

1. Peel back ECU connector boot. Attach a voltmeter positive lead to ECU terminal No. 7. Attach negative lead to any good ground. Start engine and check for a steady voltage increase as RPM is increased.
2. If engine does not run, check engine speed sensors. If engine runs, but voltage does not increase, replace ECU. If voltage increased, but vehicle tachometer did not respond, check wiring between ECU terminal No. 7 and tachometer. If okay, repair or replace tachometer.

CIS-E III

Note. CIS-E III system uses 2 versions of coils. Both versions use a power stage. DO NOT separately test function of power stage. (Scheme 10)and (Scheme 11) to determine which version you are testing.

Ignition Coil & Power Stage

1. On version one, disconnect ignition coil power stage connector. (Scheme 10) 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 pin Nos. 1 and 3. (Scheme 11) Turn ignition on. Multimeter should read approximately 12 volts.
3. If not to specification, repair break in wiring. Refer to «WIRING DIAGRAMS - CEC»(/audi/200/c3-1988-1991/remont/wiring-diagrams-engine-performance/#wiring-diagrams-cec). Connect multimeter between terminal No. 2 and No. 3.
4. Turn engine over with starter while reading 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 ICU. If wiring checks satisfactory, replace ICU.

Scheme 9

Scheme 10

Secondary Resistance

1. Check wiring between power stage and ignition coil and power stage ground wire for corrosion and damage. On version 1, disconnect ignition coil power stage connector and ignition coil wire. (Scheme 10)
2. On version 2, disconnect ignition coil power stage connector and remove screw from top of assembly. (Scheme 12) 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 10) On version 2, disconnect ignition coil power stage connector and remove screw from top of assembly. (Scheme 12)
2. Connect Multimeter (US 1119) between terminals No. 1 and No. 15. (Scheme 13)and (Scheme 14). 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.

Scheme 11

Scheme 12

Scheme 13

Hall Sender

1. Disconnect coil wire from distributor cap. Using a jumper wire, ground coil wire. Disconnect hall sender-to-ICU harness connector.
2. Connect multimeter between terminals No. 1 and No. 3 of connector "D". (Scheme 15) Turn ignition on. 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 on. 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 16) Also see «WIRING DIAGRAMS - CEC»(/audi/200/c3-1988-1991/remont/wiring-diagrams-engine-performance/#wiring-diagrams-cec) article in this section.
8. If hall sender and wiring between connector "D" and ICU connector tested satisfactory, replace ICU. (Scheme 15)

Scheme 14

Scheme 15

Scheme 16

1. This check is necessary only if no ignition spark is present. Remove harness connector from output stage of ignition coil and connect LED Tester (US1115) to terminals 2 and 3. see scheme 17
2. Crank engine and observe LED light on tester. If LED flickers, Hall Effect sensor is okay.
3. If LED does not flicker, remove harness connector from Hall Effect sensor on distributor. Connect multimeter to outer connections of harness connector. Turn on ignition. Voltage to Hall Effect sensor from ECU should be 9 volts minimum. If voltage is low, check battery, battery cables, all wiring and ECU.

IDLE SPEED, CO LEVEL & IGNITION TIMING

Ensure idle speed and ignition timing are set to specification. For adjustment procedures, see ADJUSTMENTS article.

4-CYLINDER IDLE SPEED & CO LEVEL SPECIFICATIONS

5-CYLINDER IDLE SPEED & CO LEVEL SPECIFICATIONS

4-CYLINDER IGNITION TIMING

5-CYLINDER IGNITION TIMING

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to TESTS W/CODES article. If no hard codes are found in self-diagnostics, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO-START, etc.), or intermittent diagnosis procedures.

See also:
• FUEL SYSTEM
• WIRING DIAGRAMS - CEC
• ADJUSTMENTS
• TESTS W/CODES
• TESTS W/O CODES
• ENGINE SPEED SENSOR CIRCUITS