How to Troubleshoot a Chevrolet Silverado Ignitionby Chris Moore
A Chevrolet Silverado with a V6 engine uses a distributor-based ignition system, while a V8 engine is distributor-less. Checking your Silverado's ignition system for problems varies according to the type of engine. There are a few extra tests to perform on a distributor-based ignition system. If your Silverado has any problems starting and you know the battery is good, follow these troubleshooting steps to find where the problems lie, be it in the ignition coils, circuits, crankshaft position sensor or power train control module.
Unplug the ignition coil wire from the distributor cap and connect it to a calibrated ignition tester. Crank the engine and look for a spark at the coil wire. If a good spark appears, the problem is likely within the distributor.
Check the coil wire's resistance with an ohmmeter if no spark occurs. Replace the wire if the resistance isn't around 1,000 ohms per inch.
Disconnect the electrical connector on the ignition coil and the ignition control module. Turn the ignition to the "On" position. Check for voltage at the pink terminal on each harness connector and continuity to the battery ground at the black wire terminal. If there is no voltage, check the fuses and the under-hood electrical center's circuits to the coil and module.
Test the ignition coil's primary and secondary resistance with the ohmmeter. The primary resistance should be about 0.1 ohm and the secondary resistance should be 5,000-25,000 ohms with infinite resistance between the primary terminals and core. Replace the coil if it fails any resistance tests.
Check the ignition control module's trigger signal. Reconnect the module to its electrical connector and attach a test light's lead to the positive battery terminal. Touch the test light's probe to the coil connector's white/black terminal and crank the engine. You have a trigger signal if the test light blinks.
Disconnect the control module's electrical connector if you don't get a trigger signal. Connect a voltmeter's positive probe to the harness connector's white terminal and the negative lead to a good ground point. Set the meter on the AC volts scale and crank the engine. If you don't get 1.0 to 4.0 volts, the crankshaft position sensor is good and the related circuits have continuity, have a service center test the power-train control module.
Test the white/black wire for continuity between the ignition module and ignition coil connectors if you have good voltage but no trigger signal. Replace the ignition control module if there is continuity between the connectors.
Connect a 12-volt test light to the negative battery terminal. Unplug the electrical connector from an ignition coil and check for voltage at the pink terminal while the ignition switch is on. Check the fuses and wiring/circuit between the ignition coil connector and under-hood electrical center if there is no voltage.
Test the black wire terminal on the connector for continuity to the battery ground. If you get battery voltage from the pink terminal but no spark at the black terminal, the problem can lie in the coil, crankshaft position sensor, wiring or power-train control module.
Check for a trigger signal from the power-train module if you have a year 2000 or older Silverado. Attach a test light's lead to the battery's positive terminal, touch the probe to the coil connector's second terminal from the left and crank the engine. Replace the ignition coil if the test light comes on and all circuits are good but there was no spark at the connector's black terminal.
Check the crankshaft position sensor and the circuits between the ignition coil and power-train control module if there was no trigger signal. If the sensor and circuits check out, have an expert look at the power-train module.