Tools - Correct Use of Timing Light on DLI System

90mazda02 Category

G
Applicable Model/s 1986-'90 RX-7 & MX-5 Miata
Subject TIMING LIGHT MALFUNCTION
Bulletin No. 001/90
Issued 6/8/90
Revised
DESCRIPTION


A Distributor-Less Ignition system (DLI) has been adopted in the RX-7 and MX-5 Miata since 1986 production. On a DLI system, discharge from the ignition coil is bipolar - one side is negative, the other positive. Therefore, if a timing light is designed to meet discharge from the negative terminal only, it will not light or will light intermittently at the positive terminal.

This condition is not a result of a vehicle malfunction, it is a problem with the design of the timing light. Please pay close attention to this situation to avoid misdiagnosis.

^ Check your timing light on an RX-7 or MX-5 Miata to see if it lights correctly on each cylinder. The light should work from either the positive or negative side. If it does light correctly, it can be used on a DLI system. If it does not light correctly, do not use it on a DLI system.

^ When purchasing a new timing light, perform the test mentioned above to determine whether or not the timing light can be used on a DLI system.