About the MK4 1.8T Engine

Common Issues with the 1.8T

• Rough Running At Idle: MAF, Ignition Coil, Spark Plug, VAC Leak, O2 Sensor, TB, CTS
• Misfires under Boost Flashing CEL: Ignition Coils, Spark Plugs
• Running Rich: Boost Leak, MAF, O2 Sensor, Coolant Temp Sensor
• Running Lean: VAC Leak, MAF, O2 Sensor, Fuel Filter
• Low Boost: Limp Mode, MBC, BOV, DV, Boost Leak, N75
• High Boost: MBC Setting, N75, Spark Plugs, Ignition Coils
• Cold Start Problems: MAF, Spark Plugs, Fuel Pump Relay, CTS
• Poor Gas Mileage: MAF, CTS, O2 Sensor, AIT Sensor
• Cat Efficiency Below Threshold: Downpipe, CAT, Rear O2, RACE FUEL
• No Start: Battery – ECU, Fuel Pump Relay, Ground
• Start For 1 Second Stall: Immobilizer
• Overheating: Waterpump, Thermostat, Head Gasket
• Oil in coolant: Oil Cooler, head Gasket, Water Wetter
• Dies While Driving: Timing belt, Boost Leak, MISC
• Shorts To ground CEL: Fuel pump relay, Bad Grounds
• Oil in your IC/IC piping: Check your PCV system

Engine Codes for Volkswagens

2000 Golf/Jetta: AWD
2001 Golf/Jetta: AWW
2002+ Golf/Jetta: AWP1997-1999 Passat: AEB
1999-2001 Passat: ATW
2001 Passat: AUG/AWM
2002-2004 Passat: AMB
1999-2000 Beetle: APH
2001+ Beetle: AWV
2002 Beetle Turbo S: AWP

*Engine code can be found stamped on the head of the motor

Volkswagen Engine Code Details

Engine Code: AWD

• Model Years: 2000 (11/99 on)
• Compression Ratio: 9.5:1
• Horsepower (SAE Net): 150hp @ 5700RPM
• Torque: 155ft. lbs.@ 1750RPM
• ECU: Motronic ME7.5
• DP Size: 55mm (2.17″)
• Turbo: K03
• OE Boost: .6 Bar (8.7psi)

Engine Code: APH

• Model Years: 2000
• Compression Ratio: 9.5:1
• Horsepower (SAE Net): 150hp @ 5500RPM
• Torque: 155ft. lbs.@ 1950RPM
• ECU: Motronic ME7.5
• DP Size: 50mm (1.97″)
• Turbo: K03
• OE Boost: .6 Bar (8.7psi)Engine Code: AWW/AWV
• Model Years: 2001 (07/00 on)
• Compression Ratio: 9.3:1 (Officially, though in practice its 9.5:1 as other 1.8t motors)
• Horsepower (SAE Net): 150hp @ 5700RPM
• Torque: 162ft. lbs.@ 1950RPM
• ECU: Motronic ME 7.5
• DP Size: 50mm (1.97″)
• Turbo: K03s
• OE Boost: .6 Bar (8.7psi)

Engine Code: AWP

• Model Years: 2002+ (06/01 on)
• Compression Ratio: 9.5:1
• Horsepower (SAE Net): 180hp @ 5500RPM
• Torque: 174ft. lbs.@ 1950RPM
• ECU: Motronic ME7.5
• DP Size: 50mm (1.97″)
• Turbo: K03s
• OE Boost: .8 Bar (11.6psi)

Engine Codes for Audi

1997-1999 A4: AEB
2000 A4: ATW
2001 A4: AWM
2002 A4: AMB2000-2001 TT 180hp: ATC,AJQ,APX,APP,ARY,AUQ
2001-2004 TT 180hp: AWP
2001-2002 TT 225hp: AMU,BAM
2003-2004 TT 225hp: BEA

*Engine code can be found stamped on the head of the motor

Audi Engine Codes Details

Engine Code: AEB,ATW,AUG

• Model Years: 1997-2000
• Compression Ratio: 9.5:1
• Horsepower (SAE Net): 150 @ 5700 RPM
• Torque: 155 ft. lbs.@ 1750 RPM
• ECU: 97-99.5 Motronic ME3.8.2/ME5.9, 2000+ is Motronic ME7.1
• DP Size: 50mm (1.97″)
• Turbo: K03
• OE Boost: .6 Bar (8.7psi)

Engine Code: AWM

• Model Years: 2001-2005
• Compression Ratio: 9.3:1
• Horsepower (SAE Net): 170 @ 5900 RPM
• Torque: 166 ft. lbs. @ 1950 RPM
• ECU: Motronic ME7.1
• DP Size: 50mm (1.97″)
• Turbo: K03s
• OE Boost: .6 Bar (8.7psi)

Transmission Information
Upgraded Clutches
If you haven’t noticed most of the 1.8t drivers are upgrading their clutches after a year. The stock clutch just isn’t up to the task of chipped HP and Torque. A basic upgrade is a stock VR6 clutch which is slightly larger and a lightweight flywheel. If you’re shooting for more power then you want to look into either a stage 2 or 3 kit which will include both a beefier clutch disk and pressure plate. brake in for a new clutch is between 500-1000 miles…not highway miles either. Neuspeed also offers clutch kits. They have a sport and race kit, the sport features a full-faced disc where the race kit has a 4 puck disc.
02J to 02M swap