2 Symptoms of a Deteriorating Ignition Module

key inside car ignition slot

The ignition module of your vehicle is the heart of your entire ignition system. Its two main roles are to create a spark strong enough to ignite the air/fuel mixture for combustion and to control the timing of the spark plugs by opening and closing the ignition coil ground circuit. The ignition module has a direct impact on the performance of the engine.

The module resembles a small electrical box with a wire harness. It is usually located on or in the distributor housing in domestic vehicles, and on the firewall or wheel-well in foreign vehicles.

Like all automobile components, the ignition module will eventually deteriorate and break. However, you can anticipate and prepare for the failure. These tips will help you recognize the two most common symptoms of ignition module failure.

1. Overheating

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Overheating is a common indicator that you could be having an ignition module problem. Ignition modules that are overheating will soon completely cease to function and in the meantime can cause cause electrical shorts, engine stuttering, lower gas mileage, power loss, stalling, and gasoline odors in the exhaust.

You can test for overheating while the car still runs. Idle the engine for 30 minutes, and then tap the module with a screwdriver. The car may stall, which would strongly suggest that ignition control module may be the cause of the overheating you're experiencing.

If you are caught with an overheated module in an emergency situation, you can cool it down with ice water, engine coolant, or refrigerant fluid. However, this is a temporary solution only to be used as a last resort until you can reach repair facilities.

2. Sudden Failure

If your vehicle stalls unexpectedly during operation and will not start again, it is likely because of loose or corroded electrical connections in the ignition module. In this case, check the switch, clean oxidized terminals, and replace broken wires if necessary.

It’s also possible the circuits may be critically damaged by overheating if the problem is not addressed after the first or second occurrence. If you cannot start the car, you need to test the ignition control module using a light timing tester to check the output of the module.

Connect the timer to the positive terminal of the battery and check the continuity of the black output wire while cranking the starter. If the light blinks, the module is good. If the light is blank or constant, the module is bad. Before you attempt to replace the control module, you must rule out other ignition system components. The module is expensive and replacing it is a laborious process. Check the ignition coil for a spark. Examine the wires at the cap, rotor, and spark plugs. If the car runs but has timing problems, use a tester light and wrench to adjust the spark plug timing according to the manufacturer’s specifications.

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