Auto Repair Q&A

Popular

Engine

Cooling System

Brakes

Suspension

Transmission

Exhaust/Emissions

Electrical

Body

Interior

Understand

Directory

Auto Repair Products

Finding Voltage Leaks in Ignition Systems

Spark plug

A simple test that should be in every mechanic's arsenal is a voltage leak test. A VLT can find many issues that are otherwise difficult to diagnose and it often solves simple problems that are frustrating, but not the end of the world. Performance issues are the most common manifestation of a voltage leak. Especially if the problem is hesitation or a sluggish feeling when accelerating.

Testing for voltage leaks is simple, but requires some setup. You'll need the engine to be running and accessible (covers off). A fire extinguisher and other safety tools should be readily at hand, just in case. You'll also need a spray bottle with water in it (your soapy water mix for finding leaks will work) and a workspace that can be darkened to dusk-like lighting conditions.

Caution: You are working with high voltage. use proper caution.

Start the engine in a relatively dark area and watch for spark jumps in the ignition system (wires, coils, connectors). If you don't see any, spray with water onto each until you do. KEEP YOUR DISTANCE while spraying.

Likely problems include bad or cracked coils, frayed wires, loose connections, etc. Repair is obvious.

Questionare