How to Identify the Routing of Spark Plug Wires

If you heard that changing spark plugs is an easy task and decided to do it yourself, you can take a few steps that might make your project more successful. The first is to identify the route that the spark plug wire takes.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Paper
• Pencil
• Digital camera

1. Establish how the motor is laid out. Always view the motor from one position. This helps when you lay out a diagram. Find the transmission and use that as the key to finding the power output side. View the motor from that side.

2. Find the spark plug wire that is furthest to the front, which is spark plug number one. Everything on that side is an odd number. It contains spark plug 1,3,5 and 7 in a V8. In a V6, it contains 1,3 and 5. Inline cylinders are designated as I. All these spark plug wires are in a row.

3. Note the side that the odd bank is on and loosen a wire. The wire is connected all the way down. Follow the spark plug wire and even remove it from the wire guide all the way down to the distributor cap.

4. Draw a picture of the cap from your position and a picture of the wire placement on the spark plugs. When you do this, always keep the same vantage point, at the back of the motor so that once you remove the wires your diagram is easy to follow.

5. Continue to add each wire to the diagram until you have identified the location of each wire's connection to the distributor cap. Numbering them gives you a way to keep track of the wires that are replaced and where they go.

Tips & Warnings

• Take a few digital photographs as you're doing the job. Also take a photo of the diagram after a successful replacement. It may sound like you are doubling the effort, but you can store the photographs of the spark plug wire's routing on your computer and save steps the next time you change the wires.
• Lay all the wires together in their order on the banks and keep the banks separate. This is another aid to find the right length of wire when you replace them.
• Some engines have a coil-on-plug ignition (COP) and you have to replace the boots. Pull the plug then the boot in this case. Some have one coil and are connected to two cylinders.
• Make certain that the engine is cool before you start this procedure.

[dks951753]

on 1/27/2009 step #2 in this article is incorrect for fords. bank #1 cylinders are as follows 1,2,3,4 and bank #2 are 5,6,7,8 from front to back. on all V8 fords! V6s ar likewise (b#1;1,2,3 & b#2;4,5,6)