Does Your Car Use Points Ignition or a Computer Controlled System?

distributor cap
An older distributor uses points.

Classic cars all had the same type of ignition system. An engine relies on spark to ignite the fuel that the carburetor sprays into the cylinder. It uses a spark plug to make this spark, something has to tell the spark plug when to fire and something else has to create enough electricity. In modern caras this is accomplished using computers. Every car built in the last 20 years or so has a central computer that tells  when to make a spark. These are called distributorless ignition systems. But suffice to say that it's all computerized these days. We are thankful for this, because computerizing the automotive ignition has made the system far more reliable and maintenance free than the old points type systems. The other side of the coin says it's a lot more expensive to repair the systems these days, especially if you have a V8 engine with a coil pack going to each cylinder. At hundreds of dollars each to replace, it can be very pricey when these things start to go bad.

How do you know if your older car has points? It's fairly simple. If you open your hood, be sure your car has a distributor cap with very thick wires coming out of the top and going to each spark plug. If you don't have a standard distributor cap like this, you don't have points. If you do have a standard distributor cap, you can open the cap up and peek inside. A points type ignition will have what are called points (duh) installed in the distributor, just below the rotor (that colored plastic part that spins around when the engine is running). The points look like a little hinge with two discs on the end of its arms. You will probably (but not always) also see w little cylinder with a single wire coming out of it attached to the outside of the distributor body. This is called a condensor. If you have a condensor hanging off the side of your distributor, there should be ignition points inside.

Before you adjust your points, be sure that you have:

With all of your other basic tune up procedures done, you're ready to adjust the points. Remove the distributor cap (you can leave the plug wires connected) and set it aside. Remove the rotor. Now you're ready.

Important: Always disconnect the battery before you work on your ignition. 

  1. Set the engine. If you look at the inside of the distributor, you will see that the center shaft isn't round where it contacts the points. It's what we call eccentric, or lobed. This lobe sticking out is what opens the points. We need to rotate the engine so that the distributor lobe is pushing the points apart at their farthest point. 
  2. Loosen the points. There is a screw in the center of the points that locks them into place. You need to loosen this to adjust the points. If you're replacing the points, leave it slightly loose so you can make your adjustments.
  3. Adjust the gap. The "gap" everybody is referring to is the distance between those two contact points at the end of your points arms. The gap is always measured with the points at their most open position in the distributor's rotation. Look up your car's gap in your repair manual . Using a feeler gauge, adjust the points until they are just closing on the feeler. You should be able to drag the feeler through the gap with just a little friction felt. 

*For a much more technical description of points ignition and its adjustment, check out this page.