When the engine is turned off fuel remains pressurized in the injectors and in the injector lines. However, if the injectors leak, the fuel pressure will drop and result in “vapor lock”.
- Check Injectors
- Fill Injector Tester with Shell Mineral Spirits 135
- Caution: mineral spirits are flammable
- Connect injector to tester
- Open pressure valve and bleed injector by operating pump lever.
- Measure opening pressure (check production number on “hex” area.)
- Up to 828 = 3.2-3.8 bar
- From 829 = 3.5-4.1 bar
- At 0.5 bar below measured opening pressure — injector should not drip within 15 seconds.
- Replace injectors which fail either test.
- Flush out new injectors with tester before installing.
- Check System Pressure
- Connect fuel pressure gauge (VW 1318)
- With engine at idle and valve lever closed read pressure guage
- Prior to 1979 = 4.5-5.2 bar
- From 1979 = 4.7-5.4 bar
- Audi 5000T = 5.2-5.8 bar
- If readings are not within specifications See page 31
- Check Control Pressure – Warm Engine
- Engine warm
- Engine running at idle speed
- Valve lever in open position
- Specifications = 3.4-3.8 bar
- If control pressure is not within specifications See page 32.
- Check Residual Pressure
- Engine warm
- Engine shut off
- Valve lever in open position
- Specifications – minimum readings:
- 1976-1980 (Some early 1980 models)
- 1.8 bar after 10 minutes
- 1.6 bar after 20 minutes
- Specifications – minimum readings:
- 1980 and later (cars with 3 bar accumuIator #431133441C)
- 2.6 bar after 10 minutes
- 2.4 bar after 20 minutes
- If residual pressure drops below minimum – See page 33.