Engine 1.9 TDI (AFN, 1Z, AAZ, AHU)

Content

1. Engine characteristics.

2. Reliability, problems and repair of engines.

3. Modifications of 1.9 TDI engines.

4. Problems and reliability of 1.9 TDI engines.

5. Tuning of 1.9 TDI engines (AFN, 1Z, AHU).

 

 

 

Characteristics of 1.9 TDI engines

 

 

Production: Volkswagen.

 

Engine brand : 1.9 TDI.

 

Years of issue: 1991-2010.

 

Cylinder block material: cast iron.

 

Engine type: diesel.

Configuration: row.

Number of cylinders : 4.

 

Valves per cylinder: 2.

Piston stroke, mm: 95.5.

Cylinder diameter, mm: 79.5.

Compression ratio: % 22.5, 19.5.

 

Engine volume, cubic cm: 1896.

Engine power, hp/rpm: 68/3700, 75/4500, 90/4000, 90/4000, 90/3750, 110/4150.

 

Torque, Nm/rpm: 140/2000-3000, 150/2400-3400, 202/1900, 210/1900, 210/1900, 235/1900.

 

Environmental standards: — .

 

Turbocharger: Garrett TB0261, KKK K03, Garrett GT1744V, Garrett GT1749V.

Engine weight, kg: ~200.

Fuel consumption, l/100 km (for Golf 3):
City - 6.8,
Track - 4.4,
Mixed - 5.0.

 

Oil consumption, gr. /1000 km: up to 500.

 

Engine oil: 5W-30, 5W-40, 10W-40.

 

How much oil is in the engine, l: 4.3.

The oil is changed, km: 15,000 (better 7,500).

 

Engine operating temperature, degrees: — .

 

Engine resource, thousand km:
According to the factory - —,
In practice - 400+,
Tuning, hp - —,
Potential - —,
Without loss of resource - —.

The engine was installed:

• VW Caddy
• Volkswagen Golf
• VW Vento/Bora
• Volkswagen Passat
• VW Polo
• Audi A3
• Audi A4
• Audi A6
• Skoda Octavia
• Audi Cabrio
• Volkswagen Sharan
• SEAT Alhambra
• SEAT Córdoba
• SEAT Ibiza
• SEAT Leon
• SEAT Toledo
• Ford Galaxy

 

 

Reliability, problems and repair of 1.9 TDI engines

 

 

Volkswagen 1.9 turbodiesels appeared in 1991 on VW Passat B3 cars. A cast-iron cylinder block with a forged crankshaft with a stroke of 95.5 mm and pistons with a diameter of 79.5 mm is used here, which makes it possible to obtain 1.9 liters of volume.

The first AAZ turbodiesels had an aluminum single-shaft 8-valve head with pre-chambers. The diameter of the intake valves was 36 mm, the exhaust valves were 31 mm, and the diameter of the valve stem was 8 mm. Then 1Z, AHU, AFN and other engines appeared, which used a cylinder head with direct injection. The diameter of the valves here is 35.9/31.5 mm, the diameter of the rod is 7 mm.
The first versions were equipped with a mechanical injection pump, then the engine was switched to direct injection. You can find out about the main differences between the versions below.

The production of 1.9 TDI engines with direct injection continued until 2010, but already in 1998 they were replaced by 1.9 TDI with pump injectors.

 

 

Modifications of 1.9 TDI engines

 

 

1. AZZ (1991 - 1998) - pre-chamber diesel with a compression ratio of 22.5 and a mechanical injection pump. There were two variants of the AAZ: with a Garrett TB0261 turbine and with a KKK K03. Both options were without an intercooler, boost pressure 0.7 bar. This internal combustion engine develops 75 hp. and 150 Nm of torque.

 

2. 1Z (1991 - 1996) - turbodiesel with direct injection with electronic fuel injection pump, with other pistons and with a compression ratio of 19.5. There is a Garrett GT1544S turbine with an intercooler, and the boost pressure is 0.95 bar. The power is increased to 90 hp, and the torque is 202 Nm at 1900 rpm.

 

3. AHU (1996 - 2001) - replacement of 1Z, which was adapted to Euro-2 environmental standards.

 

4. AFN (1996 - 1999) - analog AHU with Garrett GT1744V-VNT15 turbine with variable geometry, with different large-bore nozzle sprayers and with a different ECU. Power 110 hp. torque 235 Nm.

5. ALE (1997 - 2000) - AHU engine for US environmental standards.

 

6. AGR (1996 - 2005) - transverse version of the AHU diesel.

 

7. ALH (1997 - 2010) - the same AGR for the North American market, but with a GT1749V turbine.

8. AHH (1997 - 2001) - similar to AFN, but differs in fuel injection pump, injectors and Garrett GT1749V turbine. Power 90 hp, torque 210 Nm.

 

9. AHF (1997 - 2000) - analogue of ALH with sprayers, as on AFN.

10. AVG (1999 - 2001) - renamed AFN.

11. ASV (2000 - 2006) - replacement of AHF with other pistons.

12. ABL (1992 - 2003) - an analogue of AAZ, but with a different fuel injection pump, with a Garrett TB0254 turbine, with a changed pallet and a modified exhaust. Found only on Volkswagen T4.

 

 

Problems and reliability of 1.9 TDI engines

 

 

1. White smoke AAZ. Usually this is due to cracks in the cylinder head, which is not uncommon on AAZ. It is necessary to change the head for a whole one.

 

2. Loss of traction. In almost all cases, the problem lies in the N75 boost control valve. If this does not help, then you need to carry out diagnostics - the engine is old, there are a lot of options.

 

These diesel engines are not particularly picky about the quality of fuel, but it is better not to take risks and not to pour the first slurry that comes across.
Otherwise, these motors are very good and extremely reliable, they have a service life of 400,000 km or more.

 

 

Engine tuning 1.9 TDI (AFN, 1Z, AHU)

 

 

If your engine has not yet completely fallen apart and you want to make it go a little faster, then you can do chip-tuning. 110 hp versions chip up to 140-150 hp, while the torque will exceed 300 Nm.
Weaker variations of 90 liters. 110 liters are shown on the firmware. and 250-260 Nm of torque. Everything else does not make sense - the car is too old, there will be no super dynamics anyway.

 

 

 

Source.