Testing engine compression
Note. The compression test can only provide an indication as to whether the tested cylinder is working or not working properly. The cause of any loss can be further isolated by a pressure loss test. > 101802 Testing pressure loss
Scheme 252
1. Press pressure tester onto the relevant cylinder.
Note. Once the starter is activated, it switches on the engine for approx. seven seconds. This process should not be interrupted. The vehicle voltage must not drop below 12 V during the test. The throttle must always remain in the same position throughout the test. A mechanical pressing-on tool is not permitted. The accelerator pedal must be fully depressed during the test.
2. Have the starter actuated by a second person. Testing of this cylinder is complete when the needle of the test device ceases to rise. Keep the accelerator pedal fully depressed.
3. Deflate the pressure on the tester.
Scheme 253
4. Move the scale on to another cylinder. To do this, pull the pin once under the handle on the back --> Moving the test device on by one cylinder. see scheme 640
5. Then check the next cylinder according to number sequence (not according to firing order).
1. Fit spark plugs. For tightening torques, refer to 28 70 55 Replacing spark plugs - as of MY 2003 (Cayenne S TIP, Cayenne S MAN, Cayenne Turbo, Cayenne Turbo S, Cayenne S TIO Titan) .
2. Fit the ignition rod module fuses and the injection system.
3. Fit lid of central electrical box.
Designation Type Number Explanation Spark plug wrench VW-tool 3122 B
1. Open the bonnet.
2. Open lid of central electrical box. To do this, loosen the four fastening screws.
| WARNING | Risk of electric shocks from high-voltage ignition system and danger of damage to ignition rod modules! Connected ignition rod modules can be damaged. |
> Always remove the ignition rod module fuse.
> Always disconnect ignition rod module electrical connections.
| CAUTION | Risk of damage to components that affect the exhaust system! Unburnt injected fuel enters the exhaust system. |
> Prevent the fuel from injecting by removing the fuse.
3. Remove fuses -7- for ignition rod modules -8- and injection system. see scheme 644
4. Remove spark plugs. Refer to 28 70 55 Replacing spark plugs - as of MY 2004 (Cayenne TIP, Cayenne MAN) .