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Ignition System
- Turn ignition on and check for battery voltage,
If battery voltage is not present,
checlt wire between termi-
nal
15 and the unloader relay. See ELE Electrical Wiring
Diagrams.
- Turn ignition off.
Remove coil and inspect coil housing for hairline
cracks or
leaking casting material. Replace any
cracked or leaking coil.
NOTE-
A leaky coil may indicate a faulty Engine Control Module
(ECM). Check ECM before installing a new coil.
CAUTION-
Note location of coilground straps before coil removal; rein-
stall in the same location.
Use a multimeter to test:
Coil primary resistance at coil terminals.
Sparlt plug connector resistance.
* Compare results to specification in Table c. lgnition coil
resistance.
Table c. Ignition coil resistance
Coil secondary
resistance
Spark plug connector:
Bosch 1 .O I( ohm t 20%
1.8 ir ohm t 20%
Component
Co~l prlmary
resistance
- Replace ignition coil or sparlt plug connector if resistance
readings do not meet specifications.
4 Remove ignition coil to be tested.
Install
BMW special tool 12 7 030 (A) on coil to be tested.
Connect ground jumper between coil mounting point
(B)
and engine ground point (C).
Clip scope high pick-up lead (D) around ignition lead.
Start engine.
Compare scope pattern with diagrams in Oscilloscope
di-
agnostic diagrams.
NOTE-
When replacing ignition coils, ensure that the replacements
Terminal
1 (-) and 15 (+)
are
from the same manufacturer with the same partlcode
numbers. If individual coils with the correct specifications are
not available. all coils should be
re~laced.
Resistance
0.8 ohms
