Secondary ignition probes on 4 cylinders

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bonecrusher
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Secondary ignition probes on 4 cylinders

Post by bonecrusher » Wed Mar 16, 2016 2:50 pm

Hello Guys

I am working on this Land Rover Freelander 1.8 Petrol with distributor.

I have just begun using the pico so....

I have connected all 4 channels to the vehicle secondary ignition. Channen A pattern does not look like the rest, the other cylinders look normal, The firing line on channel A is not stable. If I switch off channel A then Channel B pattern goes off. It does this as I keep switching channels off.

With Only channel A connected and I move it across the 4 cylinders, the pattern is not like the typical secondary Ignition pattern.
Am I missing something, Is the trigger level not correctl?
Last edited by bonecrusher on Thu Mar 17, 2016 6:44 am, edited 1 time in total.

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FioranoCars
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Re: Secondary ignition proobes on 4 cylinders

Post by FioranoCars » Wed Mar 16, 2016 8:13 pm

Hi and welcome to the world of Pico!

First have you got a good earth for the scope? (ie the second fly lead "black" from the lead)
Second can you post the file (the PSdata - not the settings) here for us all to see?
A screen shot (from the edit menu) is equally helpful for those who can't download the file.

No earth will cause all sorts of issues.
Where have you taken the readings (connected the channels)?

HTH
Richard

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Re: Secondary ignition proobes on 4 cylinders

Post by Autonerdz » Wed Mar 16, 2016 11:15 pm

With Only channel A connected and I move it across the 4 cylinders, the pattern is not like the typical secondary Ignition pattern.
Am I missing something,
Yes. This is not how you approach a distributor system. You won't see any of the expected secondary features like the oscillations, etc, on the plug wires because these happen upstream from the rotor.

The correct way to hook up is to use one channel on the coil wire to parade a few engine cycles and then use a second channel for sync on a plug wire just so you can ID the cylinders on the other channel in the firing order.

Make sure when sampling secondary you show a 1 microsecond sample interval in properties so you render the needed detail.

bonecrusher
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Re: Secondary ignition proobes on 4 cylinders

Post by bonecrusher » Thu Mar 17, 2016 4:40 am

Autonerdz wrote:
With Only channel A connected and I move it across the 4 cylinders, the pattern is not like the typical secondary Ignition pattern.
Am I missing something,
Yes. This is not how you approach a distributor system. You won't see any of the expected secondary features like the oscillations, etc, on the plug wires because these happen upstream from the rotor.

The correct way to hook up is to use one channel on the coil wire to parade a few engine cycles and then use a second channel for sync on a plug wire just so you can ID the cylinders on the other channel in the firing order.

Make sure when sampling secondary you show a 1 microsecond sample interval in properties so you render the needed detail.

I will give this a shot today and update

Appreciate the reply, just to go a bit off topic here. I have been saving up for the pico for years( I am from a small sea side town in South Africa). Always admire the Autonerdz, seen a few youtube vids, now you are responding to a thread I made. Its take me a long time to get here.

bonecrusher
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Re: Secondary ignition probes on 4 cylinders

Post by bonecrusher » Thu Mar 17, 2016 9:58 am

Here are some pics of the waveforms
In the first pic I used trigger pickup as C , the waveform is different to the rest
In the second pic I used trigger pickup as A, the waveform for A is different
Attachments

[The extension bmp has been deactivated and can no longer be displayed.]

[The extension bmp has been deactivated and can no longer be displayed.]

[The extension bmp has been deactivated and can no longer be displayed.]

Last edited by bonecrusher on Thu Mar 17, 2016 2:17 pm, edited 1 time in total.

bonecrusher
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Re: Secondary ignition probes on 4 cylinders

Post by bonecrusher » Thu Mar 17, 2016 10:31 am

Guys all of a sudden the wavforms appear blurry. Why does this happen
Attachments

[The extension bmp has been deactivated and can no longer be displayed.]


bonecrusher
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Re: Secondary ignition probes on 4 cylinders

Post by bonecrusher » Thu Mar 17, 2016 2:19 pm

Autonerdz wrote:The correct way to hook up is to use one channel on the coil wire to parade a few engine cycles and then use a second channel for sync on a plug wire just so you can ID the cylinders on the other channel in the firing order.
Do you mean ChA n the King lead and chB on cylinder 1

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Re: Secondary ignition probes on 4 cylinders

Post by Autonerdz » Thu Mar 17, 2016 3:38 pm

Do you mean ChA n the King lead and chB on cylinder 1
Yes. And don't be shy with the capture time just watch your sample rate and maintain it so your sample interval is 1 microsecond or faster. That way you can see trends, repeating anomalies and test under differing load conditions.

These long capture times with robust sample rates are why you have a PicoScope. No other automotive scope is capable.

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Re: Secondary ignition probes on 4 cylinders

Post by bonecrusher » Thu Mar 17, 2016 5:10 pm

Thanks for the clarification.

The last pic I posted, why is the waveform blurry on the firing line.

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Re: Secondary ignition probes on 4 cylinders

Post by bonecrusher » Sat Mar 19, 2016 10:52 am

What happens in the cse of the KING lead built in to the distributor. I am working on this ka24e engine, I have connected an inductive pick up to channel b. I just cant seem to correctly read the secondary waveform on chA the firing line is always off
Attachments
Nissan_1996_Petrol_20160319-0002.psdata
(13.42 MiB) Downloaded 92 times

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