How Do you Test Ignition Coils?

[dazsafc]

Might Seem a Silly Question, but with this Problem being common. I was wondering if it was Worth Keeping a Spare in the Glove Component. And On Ebay I see you can Buy them Cheap . But in Sets of 4 Where 1 is Faulty, but they dont know which one.
Any ideas. Would maybe just using a cheapo Tester Meter thing work if I was just checking to see if the circuit was continous

 

[Chris_H]

use your tongue and crank it over

 

[TheCake]

use your tongue and crank it over

lol.

 

[RSTuning]

PMSL but on a serious note

Don't try this at home

 

[tim124]

You could check some resistances with a miltimeter, but to be honest you are only going to find out whether its completely dead or not, and not how good it will be at sparking.

Under load (foot to the floor) the coil draws lots more current and it hard to test without proper equipment.

My coil was working fine, fitted a shift light and it worked fine on the driveway.
Went down the road and as soon as i put the engine under load the shift light went crazy.
Turns out my coil was on its way out, swapped it for a spare and everything works fine now

 

[Hawkeye]

use your tongue and crank it over

LMAO

 

[dazsafc]

My coil was working fine, fitted a shift light and it worked fine on the driveway.
Went down the road and as soon as i put the engine under load the shift light went crazy.
Turns out my coil was on its way out, swapped it for a spare and everything works fine now

How Did you know which one it was though out of the 4

 

[Chris_H]

best way to do it is run it up on the rollers with load and get the scope on it. Very easy to detect a defective component this way, expensive but efective.

After about 98 all rens were semi or fully sequential efi, so if you unplug 1 injector as you would to diagnose on an early engine it will kill 2 injectors. So you end up with 2 missfires rather than 1.

If its failing under load then normally its due to damage to the coil or the plug.

But the tongue method is fail safe...

 

[tim124]

How Did you know which one it was though out of the 4

oh yeah, mine is a mk1 so its only got 1 coil

 

[dazsafc]

Seems to Complicated. It was just With them having 4 and them being common for failing. I was gonna buy a Set of 4 Used ones and Test them to see which one out of the 4 would have been duff. So I could keep the other 3 as Spares

 

[Josh@Renparts]

to do it cheaply it would seem trial and error is the best way, not much hassle, only 1 10mm bolt for each pencil coil, Just keep switching the new one round till it runs good.