SAFETY PRECAUTIONS
Note the following when working on the fuel system
| WARNING | There is a risk of injury because the fuel is under very high pressure. Before opening high pressure area of the fuel injection system, fuel pressure must be relieved to residual pressure. To reduce remaining residual pressure, lay a clean cloth around the connector and carefully loosen connector. |
Procedures before opening high pressure fuel injection system. Refer to BEFORE OPENING HIGH PRESSURE FUEL INJECTION SYSTEM .
| WARNING | Burn risk due to escaping fuel. Because the transfer fuel pump -G6- runs briefly when the battery is connected and the driver door is opened, the voltage supply to the fuel pump control module -J538- must be disconnected before opening the fuel system. |
| CAUTION | Risk of destroying electrical components when battery is disconnected. Observe measures when disconnecting battery. Only disconnect battery with ignition switched off. |
Disconnect battery. Refer to [For transmission(s) 02E] Removal and Installation .
CLEAN WORKING CONDITIONS
Even a little contamination can lead to faults. Observe the following guidelines for cleanliness when working on the fuel system, injection system and turbocharger
- Before loosening, connections and surrounding areas must be cleaned thoroughly with engine or brake cleaner, and then cleaned area must be dried completely.
- Seal the open lines and connections immediately with clean plugs, for example, from the engine bung setVAS 6122.
- Place removed parts on a clean surface and cover them with lint-free cloths.
- Carefully cover over opened components or seal, if repairs are not performed immediately.
- Only install clean components: Only unpack replacement parts immediately prior to installation. Do not use parts that have been stored out of their original packaging (for example in tool boxes etc.).
- If system is open, do not work with compressed air and do not move the vehicle.
- Protect disconnected electrical connectors from dirt and moisture and only connect if dry.
PREVENTING PERSONAL INJURY AND DAMAGE TO INJECTION AND IGNITION SYSTEMS
To prevent personal injury and damage to the injection and ignition system, observe the following
- Do not touch or disconnect ignition coils with power output stages when engine is running or turning at starting RPM.
- The ignition must be switched off before connecting or disconnecting injection and ignition system wiring or tester cables.
- If engine is to be cranked at starting RPM without starting (for example for compression testing), disconnect connectors from ignition coils and from fuel injectors. After performing work, check and erase DTC memory.
- Only clean engine with ignition switched off.
- If electrical connectors were disconnected, faults are saved in ECM
Connect Vehicle Diagnosis, Testing and Information SystemVAS 5051B.
Start "Guided Functions" operating mode.
Generate readiness code in ECM.
TEST AND MEASURING INSTRUMENTS DURING TEST DRIVE
If special testing equipment is required during road test, note the following
Scheme 56
| WARNING | Distraction and improperly secured test equipment can lead to accidents. Risk of passenger airbag deploying in an accident. Operating testing and measuring equipment while driving creates a distraction. There is an increased risk of injury due to unsecured testing and measuring equipment. TT Coupe: Always secure testers on the rear seat with a strap and have a second person on the rear seat operate them. TT Roadster: Position passenger's seat as far back as possible. Only use the vehicle diagnosis and service systemVAS 5052 or diagnostic systemVAS 5053. Testing and measuring instruments -1- must lay flat on the passenger's thighs and be operated by him or her, as shown in the illustration. |
COOLING SYSTEM
Note the following when working on the cooling system
| WARNING | Risk of scalding due to hot steam and hot coolant. When the engine is warm the cooling system is under pressure. To reduce pressure, cover coolant reservoir cap with cloth and carefully open. |
BEFORE OPENING HIGH PRESSURE FUEL INJECTION SYSTEM
- The fuel injection system is separated into a high-pressure section (maximum approximately 120 bar) and a low-pressure section (approximately 6 bar).
- Before a component in the fuel injection system high pressure area is remove, the fuel pressure must be definitely reduced to a residual pressure of approximately 6 bar, as described in the following.
Special tools and workshop equipment required
- Vehicle diagnostic, testing, and information systemVAS 5051B
Procedure
With the ignition off, connect the vehicle diagnosis, testing and information systemVAS 5051B to the Data Link Connector (DLC) -arrow- using the diagnostic lead.
Scheme 57
Start engine and let run at idle.
Display on VAS 5051B
Scheme 58
Press the Vehicle Self-Diagnosis button -1- in the selection.
Display on VAS 5051B
Scheme 59
In selection -1-, press the "Engine electronics" vehicle system and continue by pressing the --> button.
Display on VAS 5051B
Scheme 60
In selection -1-, press the "Measured values" function and continue by pressing the --> button.
Display on VAS 5051B
Scheme 61
In button field -1-, press the 1 4 0 buttons for "Display group 140" and confirm the entry by pressing the Q button.
Display on VAS 5051B
Scheme 62
Check read-out for fuel pressure in fuel rail in display field -3-.
- A value of 35 to 45 bar is displayed when the engine is running at idle. The display shows the actual pressure in the fuel rail which is generated by the high pressure pump.
Remove the right luggage compartment side trim. Refer to Removal and Installation .
Remove the fuse 6 (on fuse panel F) -SF6- for the fuel pump control module -J538- in the fuse holder in the right of the luggage compartment.
Scheme 63
Display on VAS 5051B
With the engine still running, check the fuel pressure in fuel system display -3
- The fuel pressure decreases rapidly because the mechanical high pressure pump is no longer supplied with fuel by the electrical fuel pump.
Switch the ignition off as soon as the fuel pressure drops below 8 bar.
Note. The fuel pressure must not drop below 6 bar, because otherwise the engine will shut off (risk of catalytic converter damage).
The fuel rail will continue to be filled with fuel, but it will no longer be under high pressure.
| WARNING | Do not let fuel come into contact with skin. Wear protective eyewear and clothing when opening the fuel system. Lay clean cloths around the connection before opening the high pressure area to collect any fuel that leaks out. |
Loosen the wire at a connection immediately.
Note. If the high pressure system is not opened immediately, the pressure will increase because of post-heating.
Final procedures
Insert fuse 6 (on fuse panel F) -SF6-.
Connect the vehicle diagnosis, testing and information systemVAS 5051B while the ignition is switched off.
Start "Guided Functions" operating mode.
Generate the readiness code in the engine control module.
ENGINE CONTAMINANTS
- To prevent foreign objects from entering when working on the engine, seal open intake and exhaust channels with suitable plugs, for example from the engine bung setVAS 6122.
- If mechanical damage to a cylinder bank is found, check the intake and exhaust tract and the combustion chambers in the opposite cylinder back for foreign objects to prevent further damage.
CONTACT CORROSION!
Contact corrosion can occur if incorrect fasteners (bolts, nuts, washers, etc.) are used.
For this reason, only install connecting elements that are treated with a special coating.
Also, rubber or plastic parts and adhesive consist of non-conductive materials.
If there are doubts about the suitability of parts, generally use new parts.
Note. Only original replacement parts are recommended, they are checked and compatible with aluminum. Audi accessories are recommended. Damage due to contact corrosion is not covered by warranty.
LINES, ROUTING AND SECURING
- Mark the individual fuel, hydraulic and vacuum lines for the EVAP canister system as well as the electrical wires before disconnecting and/or removing them. This will prevent a mix-up when reconnecting them. If necessary, draw sketches or take pictures.
- Due to the limited space inside the engine compartment, be especially careful when working near moving or hot parts. This will also prevent damaging the lines.
COOLERS, CONDENSERS AND CHARGE AIR COOLERS, INSTALLING
When assembled correctly, the radiator, condenser and turbocharger may have slight impressions on their fins. This is not damage. Do no replace the cooler, condenser or turbocharger because of impressions like that.
Scheme 64
- Engine number ("engine code" and "serial number") is located at front near crankshaft ribbed belt pulley -arrow-.
- In addition, a sticker with "engine code" and "serial number" is affixed to cylinder head cover.
- Engine codes beginning with "C" are four-digit.
- The first 3 digits of the engine code stand for displacement and the mechanical structure of the engine. They are stamped in the cylinder block, including the serial number.
- The fourth digit describes the engine output and torque and depends on the engine control module.
Note. Engine code is also stamped on right engine lifting eye. The 3-digit engine code is on the type plate. The 4-digit engine code is on the type plate, vehicle data label and engine control module.
ENGINE DATA
| Code letters | BUB | CBRA | |
|---|---|---|---|
| Displacement | Liter | 3.189 | 3.189 |
| Output | KW at RPM | 184/6300 | 184/6300 |
| Torque | Nm at RPM | 320/2500 to 3000 | 320/2500 to 3000 |
| Bore | Dia. mm | 84 | 84 |
| Stroke | Mm | 95.9 | 95.9 |
| Compression ratio | 10.85 | 10.85 | |
| RON | At least | 98 (1) | 98 (1) |
| Fuel injection and ignition system | Motronic | Motronic | |
| Ignition sequence | 1-5-3-6-2-4 | 1-5-3-6-2-4 | |
| Emissions values | EU4 | LEV2 | |
| Exhaust gas recirculation | No | No | |
| Turbocharger | No | No | |
| Oxygen sensor regulation | 4 sensors | 4 sensors | |
| Variable valve timing | Yes | Yes | |
| Variable intake manifold | Yes | Yes | |
| Secondary Air Injection System | Yes | Yes | |
| Valve per cylinder | 4 | 4 | |
| (1) Super unleaded RON 95 is permissible, although with reduced power. | |||
| (1) | Super unleaded RON 95 is permissible, although with reduced power. |
FUEL SYSTEM, CHECKING FOR LEAKS
Let the engine run a few minutes at a moderate speed.
Switch off ignition.
Check the entire fuel system for leaks.
If there are leaks in spite of correct tightening specifications, the corresponding component must be replaced.
Then perform a road test and depress the accelerator pedal all the way at least one time.
Then check the high pressure area again for leaks.
VACUUM SYSTEM, CHECKING
Special tools and workshop equipment required
- Hand Vacuum Pump VAS 6213
Procedure
Check all vacuum lines in the vacuum system for
- Cracks
- Damage caused by animals
- Crimps
- Leaks and leakage
Check the vacuum line leading and to and from the solenoid valve.
If there is a fault, check the vacuum lines for the named component, but also all the vacuum lines.
If using the VAS 6213 does not produce any pressure or if the pressure drops again right away, then check the hand vacuum pump and the connection hoses for leaks.
SPECIAL TOOLS
Special tools and workshop equipment required
Scheme 65
- Hand Vacuum Pump VAS 6213