Fuel Injector: Testing and Inspection

FUEL INJECTORS, CHECKING

Checking activation
Check activation of fuel injectors See output Diagnostic Test Mode (DTM). Refer to "On-Board Diagnostics II With VAG 1551". Testing and Inspection

Special tools, testers and auxiliary items
- VAG 1598/18 test box
- Multimeter (Fluke 83 or equivalent)
- VAG 1527B voltage tester
- Connector test kit VW 1594
- Wiring diagram

Check conditions
- Engine speed sensor OK
- Fuel pump relay OK

Test sequence
- Remove upper intake manifold





- Disconnect harness connector -1- from connection -2- and connect VAG 1527B voltage tester with test leads from VW 1594 to the terminals of the harness connector.
- Disconnect harness connectors from fuel injectors 2-4.
- Operate starter and check the voltage supply for no.1 cyl. fuel injector.

- LED must flicker

- Repeat check on fuel injectors 2-4.

If the LED does not flicker:
- Switch ignition off.





- Connect VAG 1598/18 test box to ECM wiring harness.





- Check wiring between test box and connector for open circuit according to wiring diagram.
- No.1 cyl. fuel injector: terminal 2 and test box socket 24
- No.2 cyl. fuel injector: terminal 2 and test box socket 25
- No.3 cyl. fuel injector: terminal 2 and test box socket 26
- No.4 cyl. fuel injector: terminal 2 and test box socket 02

Resistance: maximum 1.5 Ohms

- Check wiring between fuel injector connector terminal 1 and relay panel for open circuit according to wiring diagram.

Resistance: maximum 1.5 Ohms

- Additionally, check wires for short circuit to one another.

Specification: Infinity Ohms

Checking resistance of fuel injectors





- Check resistance of fuel injectors individually

Specification: 15-20 Ohms

If the specification is not attained, replace fuel injector(s) as necessary.

Checking spray pattern and checking for leaks

WARNING!
- DO NOT smoke or work near heaters or other fire hazards when working on fuel system.
- The fuel system is pressurized! Before loosening hose connections or opening the test connection, wrap a cloth around the connection. Then release pressure by slowly disconnecting the hose/fitting.

Special tools, testers and auxiliary items
- Connector test kit VW 1594
- VAG 1630 digital potentiometer
- VAG 1602 fuel analyzer

Test sequence
- Remove intake manifold, upper
- Remove fuel rail complete with fuel injectors





- Hold fuel injectors in VAG 1602 fuel analyzer.





- Disconnect harness connector from Engine Coolant Temperature (ECT) sensor -G62-.
- Set digital potentiometer VAG 1630 side A to 15 k Ohms and using test leads from VW 1594 connect to terminals 1 and 3 of disconnected harness connector.
- Disconnect harness connector from ignition coil.
- Operate starter (second technician required).

- The fuel injectors must pulsate and spray in accordance with firing order.

- Switch ignition off and check fuel injectors for leaks.

- No more than 2 drops/minute may leak from each fuel injector.

NOTE: When installing the fuel injectors make sure that the O-rings are not damaged.