How can I test the spark plugs on my car?

(2010-05-30 12:20:52)

1. Marvin Says: How can I test the spark plugs on my car? I need to find out if my spark plugs are firing. What is teh best way to test the? Thanks!

2. ChadYJ92 Says: If you don't want to shock yourself, pull the spark plug out and reattach the spark plug wire to it. Then attach a test wire to the spark plug, and the other end of the test wire to a good ground in the engine compartment.

Test wire:
http://www.muellerelectric.com/images/BU3131A.jpg

Then have someone crank it over, while you watch the plug to see if it sparks.

3. chachi Says: If you are daring enough......Remove the plug and then reattach the plug wire....Hold the electrode of the plug close to the electrical ground (engine block)....Watch for spark as your buddy turns engine over...You could get a jolt from the plug if voltage finds ground thru you.....So hold it close to the block.

Remember that seeing a spark is no guarantee that ignition is going to take place in that cylinder.

4. joemong Says: easy way is with a scan tool.go into misfire data.

5. idontgivafork Says: chachi is mostly correct.that is the check to see if the plug fires at atmospheric pressure, although frequently a plug will fire at atmosphere, but not under compression.the machine for testing them is pretty much obsolete.plugs are cheap, replace em if you suspect em.

6. Paul Says: 2 ways: Remove the Plug, Connect the Plug wire to the Plug, Hold it close to or place it on the head and Crack the Engine, Look for the Spark (This needs to be done at night or in the dark so you can see the spark); Clamp a "Timing Light Pick-up" around that Plug Wire, Crank the Engine and watch the Light.

7. bandit_60 Says: take each 1 out and check them. if any of them are soaked with gas then they are,nt firing to burn the gas off. they also could be carbon up with oil too and won,t fire.

8. Country Boy Says: If you had an inductive timing light it would be easy to test every plug wire on a car in a minute or less while the motor was running. No need to start and stop it either. Hook the inductive clamp over one wire at a time. If the timing light flashes when the trigger is pulled the plug is OK. If the light doesn't flash when the trigger is pulled the plug or wire can be at fault.