Injection Quantity and Spray Pattern of Fuel Injectors, Checking For Leaks
Injection Quantity and Spray Pattern of Fuel Injectors, Checking for Leaks
Test conditions
• Fuel pressure OK.
Removing fuel rail line
- Remove engine compartment cover.
- Remove vacuum hose from fuel pressure regulator (not on BGK engines).
- Disconnect connector from fuel injectors, remove cable ties if necessary.
- Remove fuel distributor from intake manifold and pull off from intake manifold with fuel injectors upward.
Injectors, checking for leaks
- Insert fuel injector to be tested into measuring container of fuel injection quantity tester (V.A.G 1602).
- Connect test box with adapter cable, 121-pin (V.A.G 1598/31) to ECM wiring harness. Do not connect ECM => [ Wiring and Components, Checking with Adapter Cable VAG 1598/31 ] Wiring and Components, Checking With Adapter Cable VAG 1598/31.
- Bridge terminals 1 and 65 at test box using adapter cables from connector test set (V.A.G 1594C) (this step supplies Ground (GND) to one side of relay coil of Fuel Pump (FP) relay).
- Switch ignition on.
• After switching ignition on, Fuel Pump (FP) will run continuously, even with engine not running for the following reason: after switching ignition on, Fuel Pump (FP) relay supplies continuous B+ via central electronics. Ground is supplied to the FP relay via the bridge in the test box.
- Check injectors for leaks (visual inspection). Only 1 to 2 drops per minute may emit from each valve when fuel pump is running.
- If fuel loss is greater, turn off fuel pump (switch ignition off) and replace faulty fuel injector.
Injection quantity, checking
Test conditions
• Adapter pin, 121-pin (V.A.G 1598/31) connected to ECM wiring harness.
- Insert fuel injector to be tested into measuring container of fuel injection quantity tester (V.A.G 1602).
- Connect one terminal of fuel injector to engine Ground (GND) using an adapter cable and an alligator clip from connector test set (V.A.G 1594C).
- Connect second contact of fuel injector with remote control (V.A.G 1348/3A), adapter cable (V.A.G 1348/3-2) and assisting cable to Positive (B+).
- Bridge terminals 1 and 65 at test box using wires from connector test set (V.A.G 1594C).
- Switch ignition on.
• Fuel Pump (FP) must run.
- Operate remote control (V.A.G 1348/3A) for 30 seconds.
- Perform measurement with all fuel injectors.
• While checking the injection quantity, the spray pattern should also be checked. Spray pattern must be the same for all fuel injectors.
- After all four fuel injectors (bank 1/bank 2) have been activated, place measuring glasses on an even surface.
Specified value per fuel injector:
If specified value is not obtained for all fuel injectors:
- Check fuel pressure (engine code BFM) => [ Fuel Pressure Regulator and Residual Pressure, Checking ] Fuel Pressure Regulator and Residual Pressure, Checking.
- Check fuel pressure (engine code BGK) => [ Fuel Pressure Regulator and Residual Pressure, Checking ] Fuel Pressure Regulator and Residual Pressure, Checking.
If specified value is not obtained for a fuel injector:
- Replace appropriate fuel injector.
Installation of fuel rail with fuel injectors is the same in reverse order. Observe the following points when installing:
• Replace O-rings at all opened connection points. (To replace the front O-rings, push the O-rings over the plastic cap at the head of the injector - under no circumstances may the plastic cap be removed).
• Lubricate O-rings with clean engine oil.
• Check clips for proper seating.
• Fasten fuel rail to intake manifold with 10 Nm.
- Check fuel system for leaks => [ Fuel system, checking for proper
seal ] Fuel Pressure Regulator and Residual Pressure, Checking.