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Another common cause of a no-start condition is no spark, or no ignition. It's the first thing I check for with a crank/no start condition. No-spark conditions can have a number of causes, but for starters, we need to know if we have spark when we crank the engine. As shown in the Crank/No Start video, you can easily check for spark with a spark tester or screwdriver. In fact, with a crank/no start condition, I often check for spark first since it's usually the easiest thing to check. Just be careful, as some ignition systems pack quite a punch and you don't want to get shocked during your testing.

Spark Tester

If you find you don't have spark, the next step is to determine if the problem is in the primary or secondary side of the ignition system. The primary side of the ignition system includes all the stuff before the ignition coil. This includes the igniter or ignition module, the pick up coil or crank sensor, the cam sensor, and the ignition switch itself. This varies greatly by manufacturer, so you’ll have to do a little homework to see how your ignition system is supposed to work, as well as how to go about testing it. The short of it is that the primary side of the ignition system tells the ignition coil when to fire. If it's not told when to fire or it has a weak signal, then the coil won't work right and you won't have spark.

The testing for this varies greatly, but here are a couple of videos that explain a little more about the process of testing the primary side of the ignition system.




The secondary side of the ignition system is a little easier to diagnose since it mostly involves similar parts. The secondary side of the ignition system is everything after the ignition coil output. So if you isolate your ignition coil and you know you have spark coming out of it but it's not getting to the spark plugs, you have a problem with the secondary side of the ignition system. This could mean a problem with the distributor cap, the rotor, the wires, or the spark plugs themselves. These parts include much of the secondary side of the ignition system.

Distributor CapRotorSpark Plug WiresSpark Plug 2

With this type of failure, I usually just follow the chain from the coil to the plug to find the failure. Most times I find a bad ignition rotor or distributor cap, or occasionally a bad set of ignition wires.

Be sure to inspect the distributor cap and rotor for carbon tracking. Carbon tracking is when an electrical short is created by carbon deposits inside the distributor cap or rotor. These can be tricky to spot, but they look like tiny lines that connect different terminals inside the cap or on the rotor. This shorts out the secondary ignition and it never reaches the spark plugs.

Underside of Distro CapSpark Plug with Spark Plug Lead

I'll go out on a limb here and say that if you have a problem with the secondary side of the ignition system causing your no-start, just replace everything: the distributor cap, ignition rotor, wires (HT leads, depending where you're from), and plugs. These are maintenance items anyway so replacing them really can't hurt.

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