Porsche 928 Workshop Manual page 553

28
Ignition System
928
If battery voltage is not displayed, pull off
1. Turn off ignition and pull off multiple-pin
relay VIII and bridge terminals 30 and 87. plug on electronic ignition control unit.
Repeat voltage test on multiple-pin plug
terminals 25 and 12 of electronic ignition
control unit.
If there is now battery voltage, replace
electronic ignition relay VI I I,
2. Connect positive tester lead on terminal 7
with help of locally made test lead and
negative tester lead on terminal 19 of
electronic ignition plug. Turn engine with
the starter.
TEST POINT 3
Speed -
Reference Mark Sensor
Note:
This test can only be made with help of an
oscilloscope.
Adjust workshop oscilloscope to supplier's
instructions.
1 = Speed signal
2 = Reference mark signal
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28 - 56
Troubleshooting Electronic Ignition System
Printed in Germany