The ignition control unit is an essential part of the ignition in the vehicle. It’s effectively a computer which looks like a small electrical box with a wire harness. It can be located either in the distributor housing or on the firewall or wheel well depending on the vehicle and its manufacturer.
The ignition control unit has two main functions. The first is to close the ground circuit to the ignition coil at the correct times to control the timing of spark plugs. Its other role is to create the all-important spark to light the mixture of air and fuel in the ignition and cause combustion.
The timing of spark plugs is important. If the spark plug doesn’t spark at the correct time, there will not be the right amount of fuel mix to ignite.
Failure of the ignition control unit can be caused by overheating. If your module is overheating, you may experience a wide range of symptoms including engine stutter, stalling and power loss as well as the strong smell of fuel when checking the smell of the exhaust. Damage can also be caused by loose connections, so check for these also.