Turbocharger and charge air pressure regulating valve, checking: Testing
- Loosen bolts -arrows- and remove engine cover panel -B-.
- Connect T-piece with measuring hose of turbocharger tester VAG 1397 A to fuel pressure regulator -arrow-.
- Route measuring hose under rear edge of hood and into passenger compartment via right-hand window.
- Switch on turbocharger tester and set measuring range selector switch to position -I- (absolute pressure).
- Connect measuring hose to connection -I-.
NOTE:
- Hose connections must be completely airtight, otherwise measurements will not be correct.
- Make sure that measuring hose is not pinched at hood or side window.
- Pressing memory key M on turbocharger tester will store the last measured value until memory key M is pressed again or tester is switched off.
- The decimal point in the display flashes to indicate that the value is being stored.
- If the battery voltage of the turbocharger tester drops below the minimum level, an arrow will appear at the top left of the display.
- Before performing the test, drive the vehicle at a brisk speed for at least 3 km (without stops).
- A second mechanic is required to note the readings on the tester when the vehicle is moving.
- Observe safety notes under TURBOCHARGER AND CHARGE AIR PRESSURE REGULATING VALVE, CHECKING .
- Accelerate vehicle from 2000 RPM at wide open throttle in fourth gear, and watch rev counter.
- Press memory key -M- on turbocharger tester at 3000 RPM.
- Specification: 1.550 - 1.650 bar
NOTE: If no charge air pressure is obtained and a throbbing noise can be heard in the engine compartment, the causes can be as follows:- Air recirculation valve malfunctioning.
- Vacuum line to air recirculation valve leaking or has become disconnected.