Disconnect the ground wire from the battery.
Attention: When the battery is disconnected, the information in the electronic memory devices, such as the engine trouble memory or the radio security code memory, is erased. Disconnect the battery only when the ignition is switched off, so as not to damage the fuel injection system control unit. When disconnecting the battery, follow the instructions in sections "Radio" And "Removing and installing the battery".
Attention: On vehicles with a six-cylinder engine, the battery is located on the right in the luggage compartment next to the spare wheel.
Models 316i, 318i before August 1993:
Remove the protective cap from the ignition coil.
Disconnect the electrical wires from the ignition coil.
If plug -arrow- is pushed out, replace ignition coil.
Check the absence of microcracks on the ignition coil and, if necessary, replace the coil. If the filling compound has leaked out, a defect in the final stage in the DME control unit can be suspected.
Check the resistance of the primary winding. To do this, connect an ohmmeter to terminal 1 and terminal 15. Set value: 0.82 ohm.
Check the resistance of the secondary winding. To do this, connect an ohmmeter to terminal 15 and terminal 4. Set value: 8.25 kΩ.
Models 320i, 325i, 328i
Remove the bolt caps, unscrew the 2 bolts located under the caps.
Remove the oil filler cap and the cylinder head trim.
Disconnect the connector on each coil by pulling up the metal bracket of the connector.
Unscrew the two bolts securing each ignition coil, remove the ignition coils.
Attention: Pay attention to the paper gaskets between the ignition coils and the cylinder head. In addition, there are mass jumpers on the coils of the 3rd and 6th cylinders. When installed, they must be laid in the same places.
Models 318is/ti: Remove the ignition coil shroud and disconnect the connectors by lifting up their metal clips.
The figure shows the ignition coil connector: 1 - terminal 15, 2 - terminal 4a, 3 terminal 1.
Connect an ohmmeter to terminals 1 and 15 and measure the resistance of the primary winding of the ignition coil. Set value: about 0.3-0.5 ohm.
Attention: secondary winding resistance (between the spark plug lead, terminal 4 and ground cannot be measured.
Models 320i, 325i, 328i insert the ignition coils with paper gaskets and earth straps and screw on.
Connect and secure the connectors to the ignition coil with metal brackets.
Install the cylinder head cover.
Connect ground wire to battery.