Ignition Coil Adapter
Ignition Coil Adapter
The MAPECU Ignition coil adapter is designed to simulate an Ignition Coil load on the output of a distributor equipped OEM ECU, for example: BMW, MG, Ford, Jeep. The OEM Ignition coil (-) terminal is relocated to the Igniter output (OC). The negative going signal is then processed into a positive going pulse suitable for the MAPECU and external Igniter. It also contains a current booster to drive the external Igniter as hard as possible to minimise heat dissipation and maximise ignition coil output. Note that this diagram shows the ignition coil adapter connected to Channel 1 of the MAPECU2 or MAPECU3 for a distributor configuration. The diagram also illustrates the recommended jumper settings specific to MAPECU2 only.
Many European vehicles use ECU’s with internal igniters driving the ignition coil. An igniter is a high power transistor that amplifies the 5V ignition signal to be suitable for the primary side of an ignition coil (12V). When the igniter is turned “on” by the OEM ECU, the ignition coil builds a magnetic field which will eventually create spark at the spark plug. The period of time the igniter is tuned “on” is called the dwell period. When the OEM ECU turns the igniter “off”, the magnetic field collapses generating a large voltage in the secondary winding of the ignition coil. This large voltage ionizes the air between the spark plug gap to generate a spark igniting the fuel/air mixture. Some vehicles, for example most Japanese vehicles, use external igniters in the engine bay near the ignition coil(s). Most Audi’s also use external igniters, which is great for MAPECU! The signal from the OEM ECU to the igniter is usually 5V. This is the signal the MAPECU2 and MAPECU3 is designed to intercept for ignition timing control.
When the igniter is built into the OEM ECU, you can either modify the OEM ECU and intercept the signal going to the internal igniter transistor(s) or use the ignition coil adapter. You also require a single channel ignition coil igniter (MAPECU-SCI). Modifying the OEM ECU is a usually beyond the capability of most people, but some installers have done so to take advantage of the MAPECU’s capability.