Previous, Next, Contents, Home.

Quick-Check of Ignition System

If the engine does not start, the most fundamental step in troubleshooting the ignition system is to determine whether or not the system is creating any kind of spark at the spark plug. If a spark is present, then it is the ignition system's efficiency and accuracy or another system's function that is in question. If no spark is present, then more detailed testing of the ignition system is necessary.

To check for spark, turn the ignition off and remove a connector from one of the spark plugs. Connect it to a known good spark plug, preferably a new plug, and hold the spark plug with insulated pliers so that the outer electrode is grounded on the engine.

CAUTION-

Any test set-up other than the one described above may cause damage or inconclusive tests.

While a helper actuates the starter, look for spark in the spark plug gap. A bright blue spark indicates a healthy ignition system. A yellow-orange spark is weaker and indicates that, while spark is present and the system is functioning, it is not operating at peak efficiency. Check the condition of the ignition system components as described in 3.2 Ignition System Visual Inspection and replace any faulty components.

WARNING-

If ignition system failure is not the problem, the engine may start during this test. Be prepared to turn off the ignition immediately. Also, running the engine with a spark plug wire disconnected will damage the catalytic converter.

NOTE-

Before checking the ignition system when there is no spark or a weak spark, make sure that the battery is fully charged. See ELECTRICAL SYSTEM.

If there is no spark, test for the switching of primary voltage at the ignition coil. Connect a test light between terminal 1 (-) of the ignition coil and ground. While the starter is actuated, the test light should flash, indicating that the coil is receiving primary voltage and is being switched correctly by the ignition system.

If the light does not flash, there is a fault in the system that switches the coil, or in the wiring harness or the ignition switch. Begin further troubleshooting by checking the Hall sender as described in 3.4 Testing Hall Sender and Ignition Control Unit or 3.5 Testing Hall Sender and Coil Power Stage (CIS-E Motronic only).

If the coil is receiving voltage, or if a strong spark is observed but the engine still will not start, begin further troubleshooting with a close visual inspection and testing of the components that conduct the secondary voltage. See 3.2 Ignition System Visual Inspection and 3.3 Testing Coil and Spark Plug Wires. Table b lists more ignition system troubleshooting information. Bold numbers in the corrective action column refer to numbered headings in this section where repair information is located.

Table b. Ignition System Troubleshooting

Previous, Next, Contents, Home.