Component Tests and General Diagnostics

Spark Advance Coolant Temperature Sensor
Sensor electrical circuit closed at 45°C (113°F) or more
Sensor electrical circuit open at 30°C (86°F) or less

Spark Advance Intake Air Temperature Sensor
Sensor Resistance 950 ± 20 ohms at 10 - 38°C (50 - 100°F)



Impulse transmitter
Voltage while cranking 1.3 - 2vdc
Clearance between transmitter and body 0.35 - 0.7mm (0.014 - 0.028in)

TCI control unit
Voltage between terminals 2 (+) and 4(-) battery voltage with ignition on
Amperage reading at coil terminal 15 (engine running at idle) 1.7 - 7.0 Amps

Ignition coil
Resistance between terminals 1 and 15 (wires disconnected) 0.7 - 0.9 Ohms
Resistance between terminals 15 and 4 (high tension socket) 7.3K - 8.3K Ohms

Ballast resistor
Resistance between voltage feed and coil terminals 0.6 ohms
Resistance between voltage feed and module terminals 0.4 ohms

High voltage
Resistance across rotor contacts 1000 Ohms ± 20%
Resistance of angled caps at coil and distributor 1000 Ohms ± 20%
Resistance of shielded spark plug connectors 5000 Ohms ± 20%

Note; BMW uses solid core wire with screw on resistors at each end. Because of this, all wires should have about the same resistance, regardless of length (compared to carbon core wire in which the resistance increases with the length of the wire).