Coil and spark plug tester. Useful tech info.

[Hernandez]

i bought this tool at pepboys, its $6.99
its used to test spark plugs but we can check coils too.
Its called ADJUSTABLE IGNITION SPARK TESTER.
you connect one end to the spark plug and another one to the coil. start your engine ant there should be a spark between the gap of the tool. if there isnt a spark then you have a coil or spark plug problem.

it wont give you certain readings or a value or anything is just a basic hand tool we all should have.

 

[oddball]

Good tools, and anyone with a decent tool set should have one.
Problem with our coils is they get marginal. So you'll still see a spark. It's just not the right duration/power, or may occasionally skip.
So, failing this test is a pretty sure bet there's a big problem. Passing this test doesn't mean the coil is OK.

Have you used this one yet? Might be a PITA to connect properly. The ones that have a lead and boot are best, but even those aren't universal.

 

[Frogman]

Problem is, most coils only show signs of failure under high load (higher RPM). You try counting sparks at ~40 times a second and let us know how it works out. :lol:

There is a good way to test simple ignition coils like FORD coils with a meter and get more accurate results of what the coil will do under high loads, but I can't remember where I've sees it.

 

[joegr]

Problem is, most coils only show signs of failure under high load (higher RPM). You try counting sparks at ~40 times a second and let us know how it works out. :lol:

There is a good way to test simple ignition coils like FORD coils with a meter and get more accurate results of what the coil will do under high loads, but I can't remember where I've sees it.

The resistance checks don't work for the typical LS coil failure, which is internal high voltage breakdown. The only thing that works is to look at them with an oscilloscope while they are stress tested.

The resistance checks and the spark gap test will only detect failed coils. They won't pick up coils that are marginal due to internal discharges.

 

[Hernandez]

you are all correct, as i said this wont give you a complete reading or tell you when it fails or anything 100% reliable. but it will give you an idea. as i posted the other day i am having trouble with my coils.

Have you used this one yet? Might be a PITA to connect properly

yes i tested the ones that i could reach. found out that one coil wasn't working AT ALL.
right not im going to remove manifold and change the coils to the other side and test them too.

 

[Frogman]

The resistance checks and the spark gap test will only detect failed coils. They won't pick up coils that are marginal due to internal discharges.

I never mentioned resistance testing. And an oscilloscope IS a meter of sorts.

Again, I don't remember the testing procedure, but it was more involved than just a simple OHM reading.