is there a way to test a coil ? may sound thick ! having trouble starting engine checked obvious things

power it up and put it on your tounge (this is a joke btw) if you wake up in hospital you know the coil works.

[Edited on 10/1/07 by graememk]

Locost way is to connect a lead & plug (with plug earthed) and then apply 12V to the coil terminals. If you get a fat blue spark it works !

If you pull it out and your girlfriend gets pregnant it was working...

Oh sorry, wrong type of coil.....

also their components

i mean if a coil sparks it still doesn´t mean its in a good condition

i would search for a known good one and compare...

have seen coil issues

a spark is one thing 50 a sec is another

Tks

[Edited on 10/1/07 by tks]

I swapped one on the neighbours car not long ago. As said, get a known good one. We put a plug lead and plug in the king lead from the coil and turned it over with the plug earthed to the block and it sparked about 5 times then died gradually.

is you have a DVM, set to resistance/ohms, reomve coil and put across + and -ve terminal;

you should see 3 ohm for standard coild, 1.5 ohm or ballasted type. Higher resistance or open circuit indicates problem.,

Do the same but one porbe on the can and other in the king lead - there should eb continuity, not done it but would expect in range of 100 - 10 K ohm; again if open circuit, then dead.

then refit ad do as ^^^ suggested.

Measuring resistance of primary and secondary and show up opens or shorts, but won't tell you if the coil is breaking down under high voltage. Likewise, a coil can work perfectly in open air but fail when trying to fire a plug under compression. Substitution is the only easy way of diagnosing a duff coil.

You can get very simple spark gap gauges (I use one myself) they have a coloured scale and you can open the gap the spark jumps till it stops, then read off the scale to see just how awful it is.

Simple is best...

I have found that having the spark just jump across the plug gap means very little, as it can still be too weak


[Edited on 11/1/07 by macnab]

quote:

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Originally posted by Peteff
I swapped one on the neighbours car not long ago. As said, get a known good one. We put a plug lead and plug in the king lead from the coil and turned it over with the plug earthed to the block and it sparked about 5 times then died gradually.

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hmm certainly leaving the ignition on with the engine off does a good job of cooking the coil.