Porsche 928 Workshop Manual page 65

03
Maintenance, Selfdiagnosis
928
The tester is now active. if knocking occurs,
this will be indicated by the tester, elg.:
Display:
To restart knock detection, press the green
key until the clear symbol appears again.
A knock display of Z- 5.0 (50) indicates a fault.
The function display will change to "r" after 10
000 ignition firings have elapsed.
Display:
Counting is now terminated.
The number of knocks is displayed in "per mil".
23 knocks have been counted in this example.
Knock detection must be carried out until the
function display switches over from the clear
symbol to the knock detection symbol.
This is always the case after 10 000 ignitions
have taken place. All occurring knocks are
added up and displayed as the end result.
Possible faults:
Defective bucket tappets
Connecting rod damage
Damage to the crankshaft drive
Press the green and yellow keys simultaneous-
ly to leave knock detection mode, until the fol-
lowing display appears.
I-
03- 18 Knock detection
Printed in Germany - Xx, 1988
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