Carburetor Pierburg 2EZ — adjustment on the engine (Opel Ascona C)

The following checks and adjustment procedures are not required under normal conditions and should only be performed if the adjustments described in Section 15 do not allow the carburetor to operate properly. They may also be required after removing and overhauling the carburetor.

Fast idle

1. The engine must be at normal operating temperature and the idle speed and mixture composition must be properly adjusted. To make work easier, remove the air cleaner.

2. Set the fast idle screw to the second highest step on the fast idle cam. Connect a tachometer to the engine. Check that the air damper is fully open.

3. Start the engine without pressing the gas pedal and compare the engine speed with the value specified in the Specifications. If adjustment is necessary, break off the plug covering the fast idle speed adjustment screw and adjust the speed with it (see photo).





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4. Once the desired speed has been achieved, turn off the engine and disconnect the tachometer.

Air damper lowering (opening) mechanism

5. Remove the air cleaner.

6. Unscrew 3 screws, remove the retaining ring and then the choke cover. There is no need to disconnect the cooling system hoses, just move the cover to the side. Note how the end of the bimetallic spring is attached to the air damper actuator lever (see photo).



7. Move the air damper drive lever until it is completely closed. Set the fast idle screw to the highest cam ledge.

8. Apply vacuum to the air damper lowering (opening) unit (on the hose closest to the carburetor body). Press the air damper actuator lever slightly in a clockwise direction (as for closing the damper) and measure the gap between the edge of the valve and the wall of the neck, inserting a drill of the appropriate size between them (see photo).





9. If adjustment is necessary, turn the adjusting screw located on the side of the choke housing (see photo).



10. Replace the choke cover, making sure that the end of the spring is hooked onto the choke drive lever. When tightening the screws, align the marks on the choke cover with the marks on its body (see photo).

Vacuum Blocks - Checking for Leaks

11. If you have a vacuum source with a vacuum gauge, apply a vacuum of approximately 300 mbar to the air damper lowering (opening) block (on the hose closest to the carburetor body). Shut off the vacuum source and check if the unit holds the vacuum. If the block is leaking, find and repair or replace the leaking part.



12. Check the secondary throttle valve vacuum block in the same manner.

13. If you do not have a vacuum source, the tightness of the vacuum blocks can be checked by trial replacement.