How can you troubleshoot an engine with no spark?


Quick Answer

Troubleshoot an engine with no spark by first checking some of the common problems associated with a lack of spark. Common issues include crank sensor problems, ignition module problems and output voltage problems.

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Full Answer

For ignition coil problems, disconnect all leads to separate the coil pack. If need be, set the ohmmeter at a low range, and recalibrate it. Check the primary resistance reading by connecting the ohmmeter leads to the primary terminals on the ignition coil. Replace the coil if the reading is more than 2 ohms. Check the secondary specification by attaching ohmmeter leads to the coil’s secondary terminal. Replace the coil if the reading is outside the specified range of 6,000 to 3,000 ohms.

Check the effectiveness of the ignition module and the crankshaft sensor circuit by connecting the halogen headlamp to the spade terminal that fixes the ignition module to the coil. Crank the engine -- if the headlamp flashes, then the ignition module and the crankshaft sensor circuit are working properly. If the engine is cranking but the head light fails to flash, change the crankshaft censor circuit.

A faulty crank position sensor normally sets a wrong code, so use a scan tool to check the code and the crank sensor. Unplug the electrical connector to check the magnetic crack sensor. Check if the resistance is in the specified range between the terminals. Change the sensor if the resistance is outside the range.

Carry out an output voltage check by connecting the sensor, and note the voltage across the module terminal while cranking the engine. Remove the sensor, and clean it if the voltage output is low. Put it back, and test again.

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