Open Fuel Injectors, Checking

WARNING: This page is about a different car, the 2015 Audi A7 Quattro and 2014 Audi A7 Quattro. However, it is still accessible from the selected car via links, so may be relevant.

Open injector means: the nozzle needle does not close all of the way and fuel leaks into the cylinder.

Special Tools And Workshop Equipment Required

Hand Vacuum Pump VAS 6213
Make an -adapter- for the return line.

Fig 1: Hand Vacuum Pump
Courtesy of AUDI OF AMERICA, LLC

Procedure

-- Remove the engine cover, refer to ENGINE COVER, REMOVING AND INSTALLING .

-- Clean all fuel rail connections with engine or brake cleaner and dry off.

CAUTION:

Danger of malfunction caused by dirt.

Observe, refer to CLEAN WORKING CONDITIONS .

Check One Cylinder After Another.

Starting with cylinder 1.

-- Remove the fuel supply hoses from the fuel injectors to be checked by pressing both retaining straps down while pulling up on the center piece to release -arrow-.

Fig 2: Center Piece On Retaining Strap

Courtesy of AUDI OF AMERICA, LLC

NOTE:

The illustration Fig 2shows cylinder bank 1.

-- Connect the Hand Vacuum Pump VAS 6213 with the custom adapter, to the return connection from the injector to be tested.

-- A vacuum pressure of -500 mbar (-7.25 psi) is applied using the Hand Vacuum Pump VAS 6213.

Fuel injectors are OK when the pressure remains constant for about 30 seconds.

If an injector is faulty, then the pressure will drop to 0 bar again within 2 to 3 seconds.

Repeat the test if necessary. Watch the Hand Vacuum Pump VAS 6213 for a loss of pressure.

-- Replace any defective fuel injectors, refer to FUEL INJECTORS, REMOVING AND INSTALLING .

Assembling

-- Inspect the O-ring on the fuel return line connection for damage or deformation.

Replace the O-ring if is it Damaged or Bent.

NOTE:

Lubricate all of the O-rings with assembly oil or engine oil before installing.

-- Carefully press the return line connections over the sealing ring and onto the fuel injector. The connection must engage audibly. Then press the release pin down carefully.

Fuel System Leak Test

-- Let the engine run a few minutes at idle without pressing the accelerator pedal and then stop the engine. The fuel system bleeds itself.

-- Check the entire fuel supply system for leaks.

Replace any leaking parts.

-- Perform a road test where the accelerator pedal is pressed all the way down at least one time. Then check the high pressure area again for leaks.

-- Install the engine cover, refer to ENGINE COVER, REMOVING AND INSTALLING .