Spark At Coil Test
See Figure 1
Since there are 3 independent coils in the assembly, each coil must be checked individually.
- Remove the cable from the No. 2 spark plug, then insert a clean spark plug into the spark plug boot.
Due to the high secondary voltage and risk of electrical shock, it is advisable to wrap a thick, dry cloth around the boot before grasping it.
- Ground the plug to the engine (touch the spark plug metal body to the engine block or other piece of metal on the car).
- Crank the engine and look for spark across the electrodes of the spark plug.
- Repeat the test for the five remaining cylinders. If there is no spark during all cylinder tests, refer to the failure-to-start test. If one or more tests indicate irregular, weak or no spark, refer to the coil test.
See Figure 2
Coil one fires cylinders 1 and 4, coil two fires cylinders 2 and 5, coil three fires cylinders 3 and 6 for the 3.3L and 3.8L engines. Coil one fires cylinders 1 and 5, coil two fires cylinders 2 and 6, and coil three fires cylinders 3 and 4 on the Premier and Monaco 3.0L engine. Each coil tower is labeled with the number of the corresponding cylinder.
- Unplug the ignition cables from the coil terminals and the spark plugs. Make certain to label them before removal. Measure the resistance of the cables. Resistance must be between 3,000-12,000 ohms per ft. (30.5 cm) of cable. Replace any cable not within tolerance.
- Unplug the electrical wiring harness connector from the coil pack.
- Measure the primary resistance of each coil. At the coil, connect an ohmmeter between the B+ pin and the pin corresponding to the cylinders in question. Resistance on the primary side of each coil should be 0.5-0.7 ohms for the 3.3L and 3.8L engines, and 0.45-0.65 ohms for the 3.0L engine. Replace the coil with a new one if the resistance is not within tolerance.
- Remove the ignition cables from the secondary towers of the coil. Measure the secondary resistance of the coil between the towers of each individual coil. Resistance for the 3.3L and 3.8L engines depends on which manufacturer made the coil being tested. If the coil was manufactured by Diamond, the resistance should be 11,600-15,800 ohms; if the coil was made by Toyodenso, the resistance should be 11,500-13,500 ohms. On the 3.0L engine, the resistance should be 7,000-14,000 ohms. If the coils' resistance are not within specifications, the coil must be replaced.
REMOVAL & INSTALLATION
- Disconnect the negative (-) battery cable.
- Unplug and label the spark plug cables from the coil pack.
- Detach the electrical wiring harness connector from the coil pack.
- Loosen and remove the coil mounting screws.
- Remove the ignition coil from the engine.
- Set the ignition coil back in place and secure with the mounting screws. The mounting screws should be tightened to 9 ft. lbs. (12 Nm).
- Plug the electrical wiring harness connector back into the coil pack.
- Attach the spark plug cables to the ignition pack. making certain the cables are attached to the correct coil towers.