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. Reduce the fuel pressure down to residual pressure before opening high pressure area of the fuel injection system. To reduce remaining residual pressure, place 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. |
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 in the fuse holder in the right of the luggage compartment.
Scheme 60
To prevent personal injury and damage to the injection and ignition system, observe the following
- Turn off the ignition before disconnecting and connecting the wiring for the injection and ignition system. This includes tester cables as well.
- Only clean engine with ignition switched off.
- If electrical connectors were disconnected, faults are saved in ECM
Connect the vehicle diagnosis, testing and information system VAS 5051B.
Start "Guided Functions" operating mode.
Generate readiness code in Engine Control Module (ECM).
| CAUTION | Danger of causing damage to electrical components when disconnecting the battery. Complete the steps for disconnecting the battery. Turn off the ignition and disconnect the battery. |
Disconnect the battery. Refer to [For transmission(s) 02E] Removal and Installation .
Note the following when working on the cooling system
| WARNING | Risk of scalding due to hot steam and hot coolant. The coolant system is under pressure when the engine is warm. Reduce pressure by covering coolant reservoir cap with a cloth and carefully open. |
If it is necessary to use testing and measuring devices on road tests, observe the following
Scheme 61
| 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 system VAS 5052 or diagnostic system VAS 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. |
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.
- Immediately seal off lines and connections with clean plugs or protective caps.
- 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.
- Make sure no fuel gets onto the fuel hoses. If necessary, wipe off the fuel hoses immediately.
- Protect disconnected electrical connectors from dirt and moisture and only connect if dry.
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 System VAS 5051B
Procedure
Turn off the ignition and connect the VAS 5051B to the Data Link Connector (DLC) using the diagnostic lead.
Scheme 62
Start the engine and let it run at idle.
Display on VAS 5051B
Scheme 63
Press the OBD button -1-.
Display on VAS 5051B
Scheme 64
Press "engine electronics" listed in the menu -1- and then press the --> button to continue.
Display on VAS 5051B
Scheme 65
Press the "measured values" listed in the menu -1- and then press the --> button to continue.
Display on VAS 5051B
Scheme 66
Press the 1 4 0 buttons in the button field -1- for "display group 140" and then press the Qt button to confirm.
Display on VAS 5051B
Scheme 67
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.
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.
Turn 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).
Connect the VAS 5051B while the ignition is switched off.
Start "Guided Functions" operating mode.
Generate the readiness code in the engine control module => .
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.
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 set VAS 6122.
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
When assembled correctly, the radiator, condenser and turbocharger may have slight impressions on their fins. It is not damage. Do no replace the cooler, condenser or turbocharger because of impressions like that.
Scheme 68
Scheme 69
- The engine number ("engine codes" and "serial number") are located at the engine/transmission joint -arrow-.
- The engine codes are also stamped on the right side of the cylinder head -2- and on the cylinder block -1-.
- In addition, a sticker with "engine codes" and "serial number" is affixed to the toothed belt guard.
- 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. The 4-digit engine code is on the type plate, vehicle data label and engine control module.
ENGINE DATA
| Identification codes | CDMA | |
|---|---|---|
| Displacement | Liter | 1.984 |
| Output | KW at RPM | 195/6000 |
| Torque | Nm at RPM | 350/2500 to 5250 |
| Bore | Diameter mm | 82.5 |
| Stroke | Mm | 92.8 |
| Compression ratio | 9.8 | |
| RON | At least | 98 1) |
| Ignition sequence | 1-3-4-2 | |
| Emissions values | EU4 | |
| Exhaust gas recirculation (EGR) | No | |
| Turbocharger | Turbocharger | |
| Knock control | Yes | |
| Charge air cooler | Yes | |
| Oxygen sensor regulation | 2 sensors | |
| Variable valve timing | Intake | |
| Variable intake manifold | No | |
| Secondary Air Injection (AIR) System | No | |
| Valve per cylinder | 4 | |
| 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.
Turn off the 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.
CYLINDER BORE, CHECKING
A shadow or a shiny spot on the wall of the cylinder does not mean the cylinder bore is damaged as long as the cross-grinding is still visible.
Always measure the cylinder bore in 3 places laterally and longitudinally using cylinder gauge VAS 6078 or inside micrometer set 18-100 mm US 1033/S.
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
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 and it 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.