Ignition coil testing

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Ignition coil testing

Post by urval » Wed Mar 02, 2016 4:40 pm

Hi. I'm user of picoscope 4223. I have tested recently the motorbike ignition system. Wanted to make sure that there is a signal coming through the HT leads at the moment when engine is stalling to find out if it is fuel starvation or ignition problem. There are four cylinders on the bike and two ignition coils with two HT leads each (waste spark ignition). Used MI074 clamp but could only see pattern of the spark on one of HT lead from each ignition coils. When did the same test using strobolight the light was flashing, which means picking up the signal, from every HT lead it was connected. It shows the all four HT lead are ok. All four spark plugs looks also ok when removed from the engine. Why could I not see the spark pattern on all four HT leads when testing with picoscope?

Best Regards

Steve Smith
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Re: Ignition coil testing

Post by Steve Smith » Tue Mar 08, 2016 12:30 pm

Hello and first of all sorry for my late reply.

Would it be possible to post your Psdata file from the motorcycle?

Can I ask if the cylinder you managed to capture looked correct with the expected peak voltage and burn time?

Could you indicate the style of ignition system for your motorcycle? (Would this be C.D. Capacitive Discharge?)

Any feedback you could provide would be most helpful.

Take care………Steve

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Re: Ignition coil testing

Post by Autonerdz » Tue Mar 08, 2016 5:57 pm

Why could I not see the spark pattern on all four HT leads when testing with picoscope?
My best guess not seeing your capture is that you didn't select opposite polarity ignition probes in the software. On your paired cylinders, one cylinder will fire negatively (electrons from center to side electrode of plug) and the other cylinder fires positively (electrons from from side to center electrode).

If you don't select the proper polarity ignition probe then your pattern will be reversed and most of it will be below the scaling limit so you won't capture it.

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