Ignition Coil Resistance

Check coil case insulation resistance. Remove leads and disconnect connectors. Using an ohmmeter, measure insulation resistance between coil positive terminal and coil case. See Fig 1 If resistance is infinity, go to next step. If resistance is not infinity, replace ignition coil.
Using an ohmmeter, measure secondary resistance between coil towers of each coil. See Fig 2 . Resistance should be as specified. See IGNITION COIL RESISTANCE table. If resistance is not as specified, replace ignition coil.

Fig 1: Checking Coil Case Insulation Resistance

Courtesy of MAZDA MOTOR CORP.

Fig 2: Checking Secondary Coil Winding Resistance

Courtesy of MAZDA MOTOR CORP.

IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)

Application

Primary

Secondary

Miata

⁽¹⁾

8700-12,900

⁽¹⁾	Information is not available from manufacturer.