Interpretation of scope correlation data!

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speck
TwoWaves
TwoWaves
Posts: 63
Joined: Sun Mar 25, 2012 5:20 am

Re: Interpretation of scope correlation data!

Post by speck »

Hi technician, okay make sure you have your spark tester connected on the coil and let it fire while you have the WPS connected to whatever cyl. You don't connect the spark tester to the scope. Run the engine and you will see the EMI of that plug in your compression wave.

speck
TwoWaves
TwoWaves
Posts: 63
Joined: Sun Mar 25, 2012 5:20 am

Re: Interpretation of scope correlation data!

Post by speck »

Hi technician, I suppose your WPS is in cylinder 1.
Attachments
EMI
EMI

Technician
TwoWaves
TwoWaves
Posts: 706
Joined: Thu Apr 24, 2014 8:32 pm

Re: Interpretation of scope correlation data!

Post by Technician »

Hi speck,

I did observe that spike previously, I did put it down to a noise type spike due to other ignition coils and injectors triggering, but my tests on cylinder 1 don't have an ignition coil fitted at the time of testing. In any event given the WPS transducer is being used to show TDC, the spike is some 126 degrees after TDC, which suggests it is something else. Originally i questioned the position of the ignition event taken place, and then Volrem came along and said ignition takes place around TDC. That spike appears along way from TDC!

Technician
TwoWaves
TwoWaves
Posts: 706
Joined: Thu Apr 24, 2014 8:32 pm

Re: Interpretation of scope correlation data!

Post by Technician »

Hi Speck,

I've had a good look through the buffer files this afternoon after posting the last post. I agree with you that the spike is triggered exactly at the point of ignition taking place, although I'm not sure how reliable that spike can be taken when reading through the buffer files. When reading through then I see the spike occurring but in frame 9 I can also see a negative spike occur just before the positive spike. While I can see that the ignition/fuel injectors can and do cause noise on the signatures, I'm not really sure how reliable those spikes can be taken for accurate data!

speck
TwoWaves
TwoWaves
Posts: 63
Joined: Sun Mar 25, 2012 5:20 am

Re: Interpretation of scope correlation data!

Post by speck »

Hi technician, I have noticed that your coil was not connected during your test, since there was no EMI . Place the coil
on the cyl. head with your spark tester connected and run the engine. Also increase your time to 500ms. This spike will show you where ignition takes place. Of course it is not a secondary capture. I use extension lead to diagnose a misfire
the paddle is not good enough for that, in spite of many people praise it. However this spike or EMI is a good indicator where ignition is. I thought that is what you were after. Hope that helps

Technician
TwoWaves
TwoWaves
Posts: 706
Joined: Thu Apr 24, 2014 8:32 pm

Re: Interpretation of scope correlation data!

Post by Technician »

Thanks Speck for your valued input on this thread, it has been most appreciated. As i originally advised, this is a learning exercise for me, and with the help i've received i have learned new ideas about diagnostics.

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