Compression Pressure, Checking

WARNING: This page is about a different car, the 2009 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

Special tools and workshop equipment required

Spark Plug Removal Tool 3122B
Compression Tester Kit VAG1763
Puller - Ignition Coil T40039

Procedure

Fig 1: Identifying Engine Cover

GWWA10-10940

Courtesy of AUDI OF AMERICA, LLC

Engine oil temperature: minimum 30 °C
Battery voltage minimum 12.5 V.

-- Remove the rear engine cover -top arrows-.

-- Remove the bolts -arrows-.

Fig 2: Identifying Coolant Hose And Coolant Reservoir

GWWA10-10850

Courtesy of AUDI OF AMERICA, LLC

-- Disconnect the connector from the Engine Coolant Level Warning Switch -F66- and move the coolant reservoir to the side with the coolant hoses -1, 2 and 3- still connected.

-- Remove the bolts -arrows- and disconnect the electrical connectors to the ignition coils on the left cylinder head.

Fig 3: Identifying Screws From Ignition Coil Wiring Harness

GWWA24-10410

Courtesy of AUDI OF AMERICA, LLC

-- Press the electrical wiring harness down slightly.

-- Disconnect the connector -3- to the fuel injectors on the rear of the left cylinder head.

Fig 4: Cylinder Bank 2 Oxygen Sensor Electrical Connectors

GWWA24-10515

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Ignore -1, 2 and 4- and -arrows-.

-- Remove the air duct -arrows-.

Fig 5: Identifying Air Duct

GWWA10-10846

Courtesy of AUDI OF AMERICA, LLC

-- Free up the fuel line -1- and the wire -2- to the EVAP canister at the air guide pipe.

Fig 6: Free Up Fuel Hose

GWWA10-10933

Courtesy of AUDI OF AMERICA, LLC

-- Remove the vacuum hose -3- from the connection on the air guide pipe.

-- Remove the air guide pipe by loosening the hose clamp -4- and opening the clips -arrows-.

-- Disconnect the vacuum line -1-.

Fig 7: Disconnect Vacuum Line

GWWA10-10821

Courtesy of AUDI OF AMERICA, LLC

-- Remove the air filter housing and, if applicable, disconnect the electrical connector -2- on the rear side at the Intake Air Switch-Over Valve -N335-.

-- Remove the bolts -arrows- and disconnect the electrical connectors to the ignition coils on the right cylinder head.

Fig 8: Identifying Bolts On Right Cylinder Head

GWWA24-10517

Courtesy of AUDI OF AMERICA, LLC

-- Press the electrical wiring harness to the side.

-- Disconnect the connector -3- to the fuel injectors on the rear of the right cylinder head.

Fig 9: Identifying Bolts -Arrows- And Right Connector Bracket

GWWA24-10516

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Ignore -1, 2 and 4- and -arrows-.

-- Remove all the ignition coils using the Puller - Ignition Coil T40039.

Fig 10: Removing Ignition Coils Using Ignition Coil Puller T40039

GWWA28-0074

Courtesy of AUDI OF AMERICA, LLC

-- Remove the spark plugs with Spark Plug Removal Tool 3122B.

-- Check the compression using the Compression Tester Kit VAG1763.

NOTE:

For information on using the tester. Refer to the Operating Instructions.

-- Have a second mechanic press the accelerator pedal down all the way while operating the starter until the pressure increase is no longer displayed on the tester.

Compression pressure	bar pressure
New	14.5 to 21.0
Wear limit	14.0
Maximum difference between cylinders	3.0

Assembling

Tightening specification. Refer to OVERVIEW - CYLINDER HEAD .

Assemble in reverse order of disassembling. Note the following:

NOTE:

Secure all hose connections with hose clamps of the same type as those equipped by the factory.

-- Install the spark plugs. Refer to OVERVIEW - IGNITION SYSTEM .

-- Install the air filter housing. Refer to OVERVIEW - AIR FILTER HOUSING .

-- If the engine was started while the electrical connectors were disconnected, then the following fault is stored in the engine control module: "generate readiness code" in "Guided Functions " using the Vehicle Diagnostic Tester.