Golf GTI L4-1984cc 2.0L DOHC (9A) (1990)
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loosened engine components
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broken, loose or missing bolts
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Check knock sensor installation torque. Loosen knock sensor bolt and torque to:
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20 to 25 N-m (15 to 18 lbs.ft.)
Note
Be sure to use a torque wrench that reads accurately in this range.
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Check that knock sensors (if more than one) are connected to the proper wiring harnesses. (If necessary, refer to Campaign Circular QX)
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Check that the knock sensor wires are not damaged.
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Check knock sensor terminals for correctly matched material. If the knock sensor terminals are tin-plated, the mating connectors must be tin-plated.
If the knock sensor terminals are gold-plated, the mating connectors must be gold-plated.
If the terminals are not the same material, metal corrosion has taken place on the terminals and the knock sensor and terminals must be replaced.
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Check that the terminals have been installed in the connector in the proper position using the latest wiring diagram for the vehicle you're working on.
Note
Replacement knock sensors only have gold-plated terminals. Earlier original equipment sensors have alloy plated terminals. Both the make and female
terminals of the knock sensor connection must be of the same material.
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Road test the vehicle and check performance
If you still suspect a knock sensor problem,
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Check the fault memory (if possible)
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Check the knock sensor wiring at the ECM
If still no improvement,
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Replace the knock sensor and road test the vehicle again.