GM 19353734 Ignition Coil Assembly

To remove and install the ignition coils and ignition control module assembly, first disconnect the battery's negative terminal. If needed, remove the cooling fan for access. Unplug the module's electrical connectors and label and detach the coil wires. Remove the assembly bolts and lift it out. Separate the coils from the ignition control module by removing their bolts. If removing the ignition system assembly, disconnect the IOI harness, remove assembly-to-camshaft bolts, lift it off, and detach the housing. Disconnect coil harnesses, remove coils, and then remove the ignition control module from the cover using screws. Reinstall in the reverse order.

To check the ignition coil, start by connecting one lead of an ohmmeter to the terminal of the ignition coil lead and the other lead to the ground. Flex the leads by hand to check for intermittent opens, and the ohmmeter should always indicate infinite resistance. If it doesn't, the ignition coil is defective and needs to be replaced. Next, connect the ohmmeter leads to both terminals of the ignition coil lead and flex the leads by hand again. The ohmmeter should read a steady value between 500 and 1,500 ohms as the leads are flexed. If it doesn't, the ignition coil is defective and should be replaced. To remove the ignition coil, start by detaching the cable from the negative terminal of the battery. Then, remove the distributor cap and rotor, and if necessary, remove the distributor itself. Remove the spring clip from the distributor shaft and mark the distributor tang drive and shaft for reassembly. Set the distributor in a vise with a shop rag to protect the shaft, and use a hammer and punch to remove the roll pin from the distributor shaft and gear. Lift the ignition coil assembly straight up and remove it from the distributor, noting the order in which the pieces were removed. Reassembly is the reverse of disassembly.

Start by removing the cap and rotor of the distributor, then remove the distributor itself. Disconnect the pick-up coil leads from the module and use an ohmmeter to test for any faults. There is a need for flexing by hand to identify intermittent opens on the leads with infinity reading at all times on the ohmmeter. Then, connect one end of an ohmmeter to the pick-up coil lead terminal and flex it again checking for intermittent opens as it flexes, with a constant meter reading of 500-1500 ohms. If any of these tests fail, it means that there is a bad pick-up coil. To replace it, mark the distributor gear and shaft for reassembly in the same position, take out roll pin from distributor shaft and gear, and pry off retaining ring. Pull straight up on pick-up assembly and wipe distributor base and module clean before applying silicone lubricant between module base for heat dissipation. Drop in module attaching module base then connect pick-up pole piece assy., retainer assy., install shaft gear parts, roll pin. Ensure that teeth do not touch; after this install rotor/cap then final re-installation of distributor into engine must be made. For V6 remove distibutor from engine; disconnect wiring connector at cap; turn four latches to remove cap/coil assembly from lower housing. Take out rotor and pickup coil lead wires from ignition module. When testing an ohmmeter should be connected between pickup coil lead connector & distributor housing reading infinite resistance. Connect an ohmeter between both terminals of pickup coil lead connector and note steady values between 600-1600 ohms will indicate that you have good ones. If any of these tests fail, it indicates that there is something wrong with its pick-up coil. To replace it: mark distibutor shaft/gear for reassembly; drive out roll pin; remove gear then draw shaft out of distributor. Next, remove the magnetic shield by removing three attaching screws, followed by detaching pick-up coil, magnet and pole piece by taking off C-clip. Put back a new pick-up coil, magnet and pole piece with a thin washer, then reassemble the shaft/gear parts/roll pin making sure teeth do not touch. Inserting rotor/cap then finally reinstalling distributor into engine that is all.

Start by removing the distributor cap and disconnecting the coil. Use an ohmmeter to check the resistance across the primary connections, ensuring it is close to zero. Then, test the resistance between the primary ground and the coil secondary connector, using both solid wire and dotted line connections. If the readings are infinite, the coil needs to be replaced.

Inspect the spark plug boots for carbon tracking and deterioration.

To check the High Energy Ignition System (HEI), start by disconnecting the battery's negative terminal. Use an ohmmeter to test the coil for opens and grounds. First, on the high scale, connect the ohmmeter leads; it should show a very high or infinite resistance value. Then, on the low scale, check the coil's primary resistance, which should indicate a very low or zero resistance value. Also, check the coil's secondary resistance on the high scale; it should not show an infinite resistance. If any values are off, replace the coil. For removal, unplug the coil's high tension wire and electrical leads, and remove the mounting nuts to take out the coil. The installation process is the reverse of removal.

The ohmmeter should not indicate an infinite resistance.

If the ohmmeter does not indicate infinite resistance, it means the pick-up coil is defective and needs to be replaced.

To check the High Energy Ignition System (HEI), start by disconnecting the battery's negative terminal. Use an ohmmeter to test the coil for opens and grounds. First, on the high scale, connect the ohmmeter leads; it should show a very high or infinite resistance value. Then, on the low scale, check the coil's primary resistance, which should indicate a very low or zero resistance value. Also, check the coil's secondary resistance on the high scale; it should not show an infinite resistance. If any values are off, replace the coil. For removal, unplug the coil's high tension wire and electrical leads, and remove the mounting nuts to take out the coil. The installation process is the reverse of removal.

After lifting the ignition system assembly from the engine, detach the coil housing-to-cover screws and remove the housing from the cover.