The Autonerdz Community Forums - Help with Ignition Waveform

James H

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Help with Ignition Waveform
Feb 21^st, 2017 at 8:12am

I am looking for some help here guys in understanding these wave forms. This is a waste spark DIS system from an aftermarket electronic ignition that has replaced an old Points setup on a vintage bike. The bike runs decent but plug fouling is an issue over time and the air fuel ratio is not rich enough to be causing this problem. I believe I have an ignition problem as there are a few things that do not look right with these wave forms. Can I have your thoughts and experience please?

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Yamaha_XS650_1976_Petrol_20170221-0001.psdata (8110 KB | )

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Spence LSD Guide Picogroup Offline Posts: 8,025 Jeffersonville Pennsylvania USA Gender:	Re: Help with Ignition Waveform Reply #1 - Feb 21^st, 2017 at 9:02am Can you post a picture of the plugs?
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Spence LSD Guide Picogroup Offline Posts: 8,025 Jeffersonville Pennsylvania USA Gender:	Re: Help with Ignition Waveform Reply #2 - Feb 21^st, 2017 at 10:08am I would like to see you add a channel onto the positive side of that coil please.
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James H Senior Member Picogroup Offline Bike Nerd Posts: 165 Waterloo Ontario Canada Gender:	Re: Help with Ignition Waveform Reply #3 - Feb 21^st, 2017 at 10:14am Spence, this is the best i could do for clarity. Appreciate you taking the time.
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Spence

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Re: Help with Ignition Waveform
Reply #4 - Feb 21^st, 2017 at 11:02am

James H wrote on Feb 21^st, 2017 at 10:14am:

Spence, this is the best i could do for clarity. Appreciate you taking the time.

Works for me. Can I see the other plug as well?

As I said could you get a channel on that positive wire to that coil.

Before I get to into the air/fuel which I think needs to get moved to the leaner side we need to address this coil and ignition module first.

Spence Cool

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James H Senior Member Picogroup Offline Bike Nerd Posts: 165 Waterloo Ontario Canada Gender:	Re: Help with Ignition Waveform Reply #5 - Feb 21^st, 2017 at 3:51pm Can't show you as the customer only brought in the one to show me with the bike as he replaced them with new. I do not have the bike running at the moment as I am waiting for some carb gaskets but here is a waveform I captured with some of the info you wanted.
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Spence

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Re: Help with Ignition Waveform
Reply #6 - Feb 21^st, 2017 at 8:18pm

James H wrote on Feb 21^st, 2017 at 3:51pm:

Can't show you as the customer only brought in the one to show me with the bike as he replaced them with new. I do not have the bike running at the moment as I am waiting for some carb gaskets but here is a waveform I captured with some of the info you wanted.

Thanks for posting the capture James!

How do you feel about it?

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Spence LSD Guide Picogroup Offline Posts: 8,025 Jeffersonville Pennsylvania USA Gender:	Re: Help with Ignition Waveform Reply #7 - Feb 22^nd, 2017 at 5:51am What are you using to determine A/F?
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James H

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Re: Help with Ignition Waveform
Reply #8 - Feb 22^nd, 2017 at 12:24pm

Well, now I can show my stupidity for all to see. Here goes.

Ignition Coil Primary Current - Turn on oscillations at bottom seems okay. Dwell angle is as stated by the manufacturer. Turn off oscillations and spikes I do not believe should be there. Coil Primary resistance is 4.5 ohms so I would expect something higher than the 2 amps??

Primary Voltage - When checking with a spark gap of over 7mm both primary and secondary wave forms have high firing voltages and no burn time. I have noticed on a snap test I do not get an increase in secondary firing voltage.

I have a 4 gas and wide band 02 that I use. Unfortunately I have no way to apply a load as my dyno is not in operation at the moment.

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Spence

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Re: Help with Ignition Waveform
Reply #9 - Feb 22^nd, 2017 at 2:59pm

James H wrote on Feb 22^nd, 2017 at 12:24pm:

Well, now I can show my stupidity for all to see. Here goes.

2 things:

1. Don't worry about it. We've all been there and I won't tell anybody anyways. Lips Sealed

2. I normally am the one that gets picked on so blame me. Cool

James H wrote on Feb 22^nd, 2017 at 12:24pm:

Ignition Coil Primary Current - Turn on oscillations at bottom seems okay. Dwell angle is as stated by the manufacturer. Turn off oscillations and spikes I do not believe should be there. Coil Primary resistance is 4.5 ohms so I would expect something higher than the 2 amps??

Very GOOD!!! I would expect to see 2 to 3 times that. If the spec is 4.5 ohms then we may not be to far off the mark. What is the spec?

Do you have any other bikes we can try even if they are points and/or a different make?

James H wrote on Feb 22^nd, 2017 at 12:24pm:

Primary Voltage - When checking with a spark gap of over 7mm both primary and secondary wave forms have high firing voltages and no burn time. I have noticed on a snap test I do not get an increase in secondary firing voltage.

I saw the same thing.

How about the dynamic voltage drop on the ignition positive during coil charging. With only 2 amps did you see how much the voltage dropped? Imagine if it was 4 to 6 amps to charge the coil?

The turn off of the coil(spark plug firing) seems to long and tail off a bit. I don't feel the module is turning off cleanly

James H wrote on Feb 22^nd, 2017 at 12:24pm:

I have a 4 gas and wide band 02 that I use. Unfortunately I have no way to apply a load as my dyno is not in operation at the moment.

Fair enough. Get the dyne fixed and lets see what is up. Is the wide band Innovate or an A/F sensing system like it?

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