Fuel Injection Quantity, Spray Pattern, and Injector Sealing, Testing

Fuel Injection Quantity, Spray Pattern, and Injector Sealing, Testing





Special tools, testers and auxiliary items required

• (VAG1348/3A) with (VAG1348/3-2)

• (VAG1594A)

• (VAG1598/31)

• (VAG1602)

Test requirements

• Fuel pressure OK.

Test sequence

- Remove fuel rail with injectors installed from intake manifold. Refer to => [ Fuel Injectors ] Removal and Replacement. Do not disconnect fuel hoses.

- Connect test box (VAG1598/31) to wiring harness for engine control module. Do not connect engine control module. Refer to => [ Wiring and Component Check with Test Box VAG 1598/31 ] Wiring and Component Check With Test Box VAG 1598/31.

Testing for leaks

- Bridge terminals 1 and 65 at test box using test leads adapter kit (VAG1594A).

- Switch ignition on.

• Fuel pump should run.

- Check injectors for leaks (visual check). When fuel pump is running, only 1 or 2 drops a minute should escape from each injector.

- If a greater amount of fuel escapes, switch off fuel pump (disconnect cable bridge) and replace faulty injector. Refer to => [ Fuel Injectors ] Removal and Replacement.

Checking injection quantity

- Place injector which is to be tested in a measuring glass from injection quantity tester (VAG1602).





- Connect one injector terminal to engine Ground using a test lead and alligator clip from (VAG1594A).





- Connect second injector terminal to positive using remote control (VAG1348/3A), adapter lead ( VAG1348/3-2) and auxiliary cable.

- Bridge terminals 1 and 65 at test box using leads from adapter kit (VAG1594A).

- Switch ignition on.

• The fuel pump should run.

- Activate remote control (VAG1348/3A) for 30 seconds.

- When all three injectors of a cylinder bank have been activated, place three measuring glasses on a flat surface.

• Specification per injector: 90 to 125 ml

- If measured values for one or more injectors are outside tolerance range, stop fuel pump (switch off ignition) and replace faulty injector. Refer to => [ Fuel Injectors ] Removal and Replacement.

- Repeat test on injectors from second bank of cylinders.

- If measured values for all injectors are outside tolerance range, check fuel pressure.

• When checking the injection quantity, also check the spray pattern. The spray pattern should be the same for all the injectors.

- Install injectors with fuel rail => [ Install in reverse order, note the following: ] Removal and Replacement.