Diagnostic Scan Tools – Timing Lights and Test Probes

A responsible car owner will make the maintenance of his vehicle a priority. For fast and accurate servicing of the engine, a technician will require a set of diagnostic scanning tools. These tools will provide information on the status of the battery, fuel, ignition and emission systems of the vehicle. They would also check the mechanical conditions of the engine. While some testing is basic, which primarily ensures that the engine is sound; other examinations establish if the electrical and support systems are functioning smoothly.

It is one such diagnostic scan tool, used to set the ignition timing and internal combustion engine of any vehicle. It helps determine whether or not the fuel system is plumbed correctly, its injectors are flowing cleanly with a good spray pattern and the sparkplug wires have been installed in the correct firing order.

Timing marks indicate the current timing of the spark vis-à-vis the position of the piston in the ignition system. Identification of such marks helps to set the timing of the ignition system. If a timing light is attached to the ignition circuit while the engine is running, it can easily identify such timing marks.

The two test probes of the timing light need to be connected with the battery terminals as per the polarities. The trigger on the timing light plays the part of a switch. When it is pulled, it releases a beam every time the sparkplug fires.

There are a few different types of timing lights available in the market. The spark of the ignition itself powers the low-priced ones. These consist of two test probes of which one is clamped to the battery ground and other is inserted between the distributor cap and the sparkplug wire. They use a neon bulb, which may not be too bright and requires a dim lit utility area. However, this variety of time lights has no use in newer cars as they are composed of direct ignition systems.

Alternatively, other time lights, which powered by direct current can be used. These amplify the power from the battery of the vehicle to the bulb. This emits a very bright light, making it comfortable to use even in sunlight. The AC-powered timing light is similar to its DC-powered counterpart except that the former uses a 110-volt household power as a source.