Knock Detector - Proper Installation
84saab02SUBJECT:
PROPER INSTALLATION OF BOSCH APC KNOCK SENSORS AND ROUTING OF ITS SHIELDED CABLE
ISSUE: 06/84-693
FILE IN S.I. MANUAL:
VOLUME: I
SECTION: 2
PAGE: 165
A Bosch-brand APC knock detector and shielded cables which has been improperly installed may transmit a false signal to the APC control unit.
The following must be noted anytime the knock detector has been replaced or otherwise disturbed and whenever the shielded cable from the knock detector to the control unit has been moved.
^ Knock Sensor Mounting Bolt - Never substitute the mounting bolt for the knock detector for any other bolt.
The correct bolt is Saab P/N 80-82-968 which is a M8 x 25 mm, 8.8 graded bolt. Installing washers or other types of bolt heads is prohibited.
^ Tightening Torque of Mounting Bolt - An accurate torque wrench must always be used and the knock detector bolt subsequently tightened to 15 ft.lbs. (20 N-m).
Incorrect torque may affect the internal capacitance of the sensor.
^ Routing of the Sensor Wire -
- Hoses and other engine components must be secured so that they do not come in contact with the knock sensor.
- When tying the knock sensor wire to coolant hoses, always leave a little room for hose expansion.
An expanding cooling hose could impede the signal from the knock detector and could possibly damage the shielding of the wire.
- The wire must not be tied to or allowed to come in contact with the intake manifold or the engine block.
- Avoid sharp bends when routing the wire and do not allow it to pull tightly on any of its connections.