How to Test the Engine After Spark Plug Replacement

If you just changed the spark plugs, the next step is testing the job. Everything should be alright if you replaced one wire at a time or took pictures and drew diagrams of the location of the wires from the distributor cap to the plug. Let's say you didn't. There are ways that you can test your engine to see if you got it right.

Instructions

1

Turn on the car. When you change spark plug wires the testing part is easiest. The car may not start if you connected the wrong wire to the right spot. If the car doesn't turn over, head to the library for the Chilton manual. Better yet, buy one and keep it handy.

2

Listen to the engine. If the sound of the motor running makes you want to mambo or crunk, then you may have put a wire or two on the wrong spot. The car should run smoother than it did before you changed plugs and wires; that was the whole idea for the change.

3

Hear a big bang and know that your car just backfired. This is definitely not good because, while rare, you can do some damage by connecting the spark plug wires incorrectly. The loud backfire when you test your car after you changed your spark plug wires indicates that you are one of the select few that damaged the engine or pistons.

4

Start again. This time use the dealer's manual or Chilton repair guide for your car to show you diagrams of the order of fire. Next time, you'll remember to draw your own diagram, replace one wire at a time or take a few pictures to download and use as reference.