Note.
- The temperature of the engine, the load generated by the additional equipment and the altitude at which the vehicle is operated affect the amount of vacuum in the intake manifold.
- The vacuum value decreases by approximately 2.7 kPa for every 305 m above sea level.
1. Disconnect the engine vacuum hose from the brake booster check valve.
2. Install a vacuum gauge on the engine vacuum hose.
3. Start the engine and warm up to operating temperature at idle.
4. With the engine running at idle and the air conditioning system turned off, check that the vacuum value created by the engine complies with the specification:
- Mechanical vacuum pump: 90-95 kPa.
- Electric vacuum pump: 40-70 kPa.
5. Turn off the engine.
6. If the engine vacuum is correct, go to step 10.
7. If the vacuum generated by the engine is not correct, check the engine vacuum hose for the following:
- Loose connection to the engine.
- Destruction, deformation or blockage.
- Cracks, cuts and other damage.
8. If any of the listed defects are found, replace the vacuum hose and repeat steps 2-4.
9. If there are no defects in the vacuum hose, therefore, the problem lies in the source of vacuum in the engine, it is necessary to check the vacuum system completely.
10. Remove the check valve from the vacuum brake booster.
11. Install a non-return valve on the vacuum hose.
12. Install a vacuum gauge on the check valve.
13. Start the engine and warm up at idle to operating temperature.
14. Turn off the engine.
15. Verify that the vacuum generated by the engine is within specification:
- Mechanical vacuum pump: 90-95 kPa.
- Electric vacuum pump: 40-70 kPa.
16. If the engine vacuum is correct, go to step 18.
17. If the vacuum generated by the engine is not correct, replace the vacuum booster check valve with a new one, then repeat steps 11-15.
18. Check the vacuum booster check valve gasket for the following:
- Loose connection to the vacuum booster.
- Deformation or contamination.
- Cracks, cuts and other damage.
19. If any of the listed defects are found, replace the check valve gasket with a new one.
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