Golf GTI L4-1984cc 2.0L DOHC (9A) (1990)
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Remove red vacuum line from throttle body and connect to T-piece of vacuum test gauges. Attach short vacuum hose from T-piece to throttle body.
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Start engine and let idle (engine at operating temperature).
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Press button on vacuum test gauges to read vacuum (read left gauge).
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must be at least 13 mbar (0.38 in HG)*
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If NOT, check vacuum tube in throttle body for obstruction and correct
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Increase engine speed to 3500 RPM.
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should read up to 23 mbar (0.6 inHG)(read left gauge)*
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IF NOT, check vacuum nozzle on throttle body for obstructions and correct
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Turn engine OFF.
2.
Check for vacuum signal
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Connect T-piece from vacuum test gauges to red vacuum line and connect vacuum pump to other end of T-piece.
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Start engine and let idle.
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Press button on test gauges to read vacuum.
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Activate pump until vacuum reads
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at least 23 to 27 mbar (0.6 to 0.8 in HG), idle must be noticeably erratic.
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If NOT, look for vacuum leaks at red, blue and yellow line connections and correct as necessary.
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If vacuum line connections are OK, replace EGR vacuum amplifier.
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Turn engine OFF
3.
Check EGR vacuum amplification