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Ignition Module Problems

Ignition Module Problems

Problems with the ignition module is a common issue in most automobiles. Let's discuss the possible causes and troubleshoot them.
Narayani Karthik
The ignition is a vital component that is responsible for turning on/off the primary current produced by ignition coil. This module consists of sensitive electronic components placed inside a sealed plastic housing of the control module. An electric current is passed into the control module to ignite the air-fuel mixture inside the combustion chamber. This triggers the ignition to start the automobile. But like any machine, the ignition module too is susceptible to wear and tear and regular care and maintenance is needed to avoid problems.

Ignition problems are accountable for hampering the performance of your engine. Sudden stalling of your engine when you are speeding up or failure to start the engine after repeated attempts are some of the major indications of problems. Some of the causes that lead to problems in the ignition resulting in frequent stalling of engine are listed below:
  • Engine Vacuum Leak: This is caused by loose/broken vacuum hoses in the engine.
  • Defective Speed Control: This is caused when idle air bypass circuit of engine is clogged with dirt/fuel/varnish thereby stalling the entry of fresh air.
  • Defective Airflow Sensor: When airflow sensor wire of your engine is plugged with dirt, this can lead to a problem.
  • Low Engine Compression: Low engine compression is caused because of the worn out piston rings and cylinders of engine and leaky valves.
  • Defective Coolant Sensor: Defect in coolant sensors can lead to incorrect readings of engine temperature, thereby screwing up the fuel mixture.
  • Faulty Air Temperature Sensor: Defective air temperature sensors can upset the air fuel mixture by recording wrong temperatures of the air entering the engine.
  • Fouled Spark Plugs: These are one of the major causes of engine stalling, as they do not fire at the appropriate time to start the engine.
  • Faulty MAP Sensor: MAP implies Manifold Absolute Pressure. These sensors of engine, intake vacuum, which are used for determining engine load. Faulty sensors can lead to incorrect fuel supply, thereby giving an incorrect engine load.
  • Adulterated Gasoline: If the fuel (gasoline) is adulterated with more than 10% alcohol, then the air fuel mixture will not be strong enough for the ignition to take place.
  • High Electric Load on Ignition: An ideal charging ignition must produce 13.5-14.5 Volts. But if the battery has run low on voltage, it will result in engine stalling and misfiring.
Troubleshooting is the next task to be done after the identification of the problem. So, before starting with troubleshooting, it is important to understand the working of the ignition module. The module receives its signals from a crankshaft sensor. These signals are converted to a digital format and are fed to the main engine control. The main engine control determines the engine timing for firing, generates a firing sequence and returns it back to the ignition module. Now the module ignites the firing of the primary coil by inducing a high voltage in secondary windings to fire up the spark plug. So, to troubleshoot this rapid process, follow the steps below:
  • Check Crankshaft Sensor: First locate the ignition control and turn the ignition key on. Pierce a wire into the ignition control without affecting the voltage regulator's red lead. Now attach the other end of the wire to ground. A reading of 100 mV will be displayed on your voltmeter if the crankshaft sensor is in working condition. If no reading is displayed, disconnect the crankshaft sensor and retest again for 12 Volts. With this, it is confirmed that the sensor is not working and needs immediate work around or replacement.
  • Check for Battery Voltage: Check the control module engine battery with terminal to record voltage. If there is no voltage, then there is a strong possibility of a fuse or a bad wire.
  • Check Coil Functionality: If the control module engine battery is working fine, check for the functionality of the primary coil of the control module engine. Turn off the ignition key and remove the coil. Now check the resistance units (ohm) of the coil using the voltmeter and also check the positive and negative terminals of the coil. The ideal resistance value should be 0.02 - 0.075 ohm. Any value greater than this range implies the coil is bad and needs to be replaced. Now check the functionality of the secondary coil of the control module engine. Touch the terminals of the secondary coil with the leads of voltmeter. Resistance should be 7500 - 18000 ohm. Reading surpassing this resistance, calls for immediate replacement of the secondary coil.
Most of the ignition problems are easily avoidable. Cleaning the airflow sensor wire off the dirt and fuel varnish with aerosol electronics cleanser, is an effective method to normalize the operation of an ignition. Using unadulterated gasoline and regular fuel tank cleaning will aid in proper functioning of the ignition.

Replacement of Ignition Module
By now, we all know that turning on the ignition transfers digital signals from a sensor to the distributor in ignition coil that initiates firing of spark plugs. So replacement of this module is better to be left to an experienced mechanic due to its rapid and complex process that is not visible to a naked eye. But in case, you are not keen on pinching your wallet, this activity can be carried out by self. Let's see how!

P.S. - Before jumping into this activity, make sure your diagnosis of the problem is correct. Take help of an experienced mechanic if required.

Tools Needed:
  • Service manual of the vehicle
  • Electronic testing unit (such as voltmeter)
  • Screwdrivers, pliers and wrenches
  • Overhead lighting
  • Some shop rags
Replacing the Faulty Ignition:
  • First locate the ignition module with the help of the service manual.
  • Disconnect the cables of the engine battery and remove any secondary components connected to it.
  • Dismantle the old module with the help of tools (screwdrivers, etc.) and place the new ignition in the housing.
  • Now, fix the screws and reattach the wires leading to ignition control module. Read the manual well and preferably take help of a mechanic while fixing everything back.
  • Reconnect the cables of the battery and close the hood. Turn the ignition key on and if your vehicle responds spontaneously by starting up, you have done it the right way!
Hope, the above article helped you understand the major ignition problems and how to go about fixing car starting problems. I believe by now, you are already half a mechanic!