Misfire test

[Booncha57]

Can you put a timing light on each plug wire to tell which cylinder is misfiring? When I just tried this on some of them I had a few that were consistent but not all. One of them was flashing about twice as fast as the rest, one looked completely random. There must be a reason for this, I'm just not sure if it's good or bad.

 

[Kenneth S]

Probably a bad plug wire, do a resistance test on them.

 

[Booncha57]

I just replaced the plugs and wires and I'm thinking that maybe one of the ones under the intake isn't on very good. How do I do a resistance test?

 

[Kenneth S]

Those plug wires on the intake side can be a real pain to get on correctly which could be your problem. To do a resistance test you will need one of those little testers with a guage (multi-meter) that you can check voltage with and such, and is should have instructions on how to do a resistance test, they cost around $10.00-30.00 for a inexpensive one.

 

[Booncha57]

I have one, unfortunately I do not have the instructions...

 

[Earl43P]

http://www.popularmechanics.com/how_to_central/automotive/1272351.html

http://mr2.com/TEXT/DavidKucharczyk/ignition.html



There are different ranges on the ohm meter. Always hold the two leads together and "zero" the meter, if you are using the dial type. Do it anyway and make sure it reads close to zero (continuity).

Then measure the plug wire from end to end. Each different length plug wire will be a different amount of ohms. You may have to change ranges to get a reading on the meter.

Personally, I like the mist in the dark test.

 

[Kenneth S]

Personally, I like the mist in the dark test.[/QUOTE]

I have found alot of bad plug wires using the "dark test".

 

[Booncha57]

Does a wire have to be bad for there be a problem if they are crossed or can good wires still jump spark when they are crossed?

 

[Kenneth S]

I have seen a few new ones do it.