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Have I been unlucky with my replacement coils?
james h - 12/4/15 at 07:51 PM

I thought I had damaged one of my coils (R1 carb engine), so bought another pair s/h off eBay.

Now I know the problem is actually the CDI/ECU/Ignition control unit I decided to test the coils, both sets. So the two on the car now (from eBay) and the ones I removed.

The primary winding resistance should be 1.87 to 2.53 ohms at 20 degrees Celsius. On all four, I have readings of between 4.4 ohms to 4.6 ohms. Here is a photo:

Primary winding resistance
Primary winding resistance


Are all four coils equally f**ked? Why would that be? It is a bit weird how they are all equally off by a long way.

The secondary winding resistance is within spec, and the spark plug caps are pretty close too.


gremlin1234 - 12/4/15 at 08:09 PM

what does the meter read with the probes connected together?
try changing the meter battery
try another meter - cheep digital multi meters do give a good indication, but really are not calibrated at such values


james h - 12/4/15 at 08:13 PM

quote:
Originally posted by gremlin1234
what does the meter read with the probes connected together?



Oops. Just after I posted the question I got someone else to measure it. He crossed the probes and we found that there is indeed inbuilt resistance, which brings the readings inline.

Thanks! I think I need to get a better multimeter too, like you said.


SteveWalker - 12/4/15 at 08:31 PM

Get yourself a meter with a zero button. Hold the probes together and press the button and it will then subtract the reading (resistance of the leads) from any readings that you take.