Ask the Editors: MULE Not Kicking
MULE electrical phenomena.
There was no spark when I got it, so I tracked down a defective fuel pump relay, CDI, ignition switch and one of the ignition coils. The pulse coil (crankshaft sensor) reads right at 130 Ω and with a Peak Voltage Adapter is putting out between 3.5 and 4vdc. The ignition coils (now) both read between 1.9 and 2.6 Ω on the primaries and about 12kΩ on the secondaries. The CDI has 12v on the grey and brown leads with ground on the black/yellow. All of the wires to and from the CDI pin out fine as far as I can tell.
What I am getting now, though is a single spark when you first spin the engine over and either one or two sparks when you stop spinning it over. The Peak Voltage on the ignition coil primary reads 10vdc as soon as you hit the starter and continues to drop until you release the starter, at which point it jumps up to 10vdc again for just a second.
I know that the brand new CDI from PartsShark CAN be defective, but I am looking for anything else that I might have over looked. The last time I saw this was on an ATV that had bad connections to the CDI, but that isn’t (doesn’t seem to be) the case here.
Any help or advice would be GREATLY appreciated!
We like your approach – you are checking all of the right items off. And while you mention the readings for the ignition coils, have you done any stator diagnostics? A very strong candidate for weak or intermittent spark when the CDI, rectifier and regulator all check out.
If all of this looks okay, really all that remains is the arduous task of checking for wiring shorts or bad connections by switching that meter to resistance (Ohms) and probing between runs.
The trouble with all of the usual suspects here is that it seems the problem really only manifested after some parts swaps whereas all of the other causes would simply happen as the components failed.
You’re right in thinking it is possible a brand new CDI can be faulty but before we’d come to that conclusion, we’d swap back to the original CDI you removed to see if you get the same results. If there is variation here, you found your culprit.
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