EXAMPLE: Diagnosing an Engine That Cranks but Won’t Start

Check for spark at the plugs. If none, check for spark at the coil, after removing the distributor cap, rotor, and leak cover. Ground the test light clip and check for spark from the coil, as an assistant turns the ignition switch to Start. If the coil works, there should be a spark between the spring on the coil and the test light, as the probe is brought in the proximity of the spring. You now have spark at the coil and no spark at the plugs; therefore, replace the rotor and distributor cap, since one or both may be shorting out.

If there’s no spark from the coil, check the igniter with the test light. Take a jumper wire, with alligator clips on each end, and ground out the coil spring. Touch the test light probe to the negative terminal on the coil, as your assistant turns the ignition switch to Start. If the igniter is good, the test light should blink on and off. If the test light does not blink on and off, replace the igniter. Should the coil still not spark, after replacing the igniter, replace the coil.

In real life, everything can check out but the engine can still die on you, once it gets hot and the igniter and/or coil start to break down under load. That’s why I’m not a real fan of testing igniters and coils. This diagnostic process may keep you from just throwing parts at the problem—just be aware of its limitations.

Bottom Line: ICMs and coils really take a beating in Hondas.