1. Warm up the engine.
2. Disconnect the brake booster vacuum hose from the intake manifold, and attach the vacuum gauge. (except for Euro 5 model)
3. Disconnect the brake booster vacuum hose from the intake manifold, and attach the vacuum gauge. (Euro 5 model)
4. Keep the engine at idle speed and read the vacuum gauge indication.
NOTE:
Condition of engine inside can be diagnosed by observing the behavior of the vacuum gauge needle as described in table below.
Intake manifold vacuum (at idling, A/C OFF):
Standard
−60.0 kPa (−450 mmHg, −17.72 inHg) or more
5. After inspection, install the related parts in the reverse order of removal.
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Diagnosis of engine condition by inspection of intake manifold vacuum | |
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Vacuum gauge needle behavior |
Possible engine condition |
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1. Needle is steady but lower than standard value. This tendency becomes more evident as engine temperature rises. |
Leakage around intake manifold gasket, disconnection or damage of vacuum hose |
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2. Needle intermittently drops to position lower than standard value. |
Leakage around cylinder |
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3. Needle drops suddenly and intermittently from standard value. |
Sticky valve |
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4. When engine speed is gradually increased, needle begins to vibrate rapidly at certain speed, and then vibration increases as engine speed increases. |
Weak or broken valve springs |
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5. Needle vibrates above and below standard value in narrow range. |
Defective ignition system |