The Autonerdz Community Forums - What the other guys are doing with scopes

autosparky

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What the other guys are doing with scopes
Oct 17^th, 2016 at 1:13am

http://www.tiepie-automotive.com/en/Measurement_examples

wonder how this compares to our failed Pico Diagnostics?

Now there's another feature I'm trying to figure out, (not on this web site)is called Delta N works out cylinder contribution

RPM is calculated from crank angle sensor, then they use another math channel to look at either RPM ripple or the crank angle ripple wave slopes rising and falling of each cylinder to show each cylinder contribution. It looks a bit like a relative compression current test

Tom can I post a section of an article that's been posted to me without upsetting copyright laws??

So any smart nerdz like to come up with a new math channel??

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jarvissamuel

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Re: What the other guys are doing with scopes
Reply #1 - Oct 17^th, 2016 at 6:04am

I would not go so far as to call Pico diag a failure. I still use it a fair amount, at least the older version.

The trick is not to rely exclusively on it. It is a great go or no go when suspecting a mechanical engine fault and as a bonus a neat printout can be made for the customer.

Not sure if it is the same or similar there is on guy on iATN that did a few posts I believe using a scope that had a feature called scripts using the CKP. Maybe I or someone else can dig up a link.

Sam

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Tom Roberts

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Re: What the other guys are doing with scopes
Reply #2 - Oct 17^th, 2016 at 10:13am

autosparky wrote on Oct 17^th, 2016 at 1:13am:

Tom can I post a section of an article that's been posted to me without upsetting copyright laws??

If it's online just link to it. If it's not, then it's up to you. Being in the private area it's not likely to make any one complain.

A Pico RPM channel would show CKP speed variations. The more CKP teeth, the better resolution.

In the web link you provided and going to smooth running test, I can see that they have their CKP hooked up backwards.

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Tom Roberts
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Spence LSD Guide Picogroup Offline Posts: 8,025 Jeffersonville Pennsylvania USA Gender:	Re: What the other guys are doing with scopes Reply #3 - Oct 17^th, 2016 at 12:14pm Tom Roberts wrote on Oct 17^th, 2016 at 10:13am: I can see that they have their CKP hooked up backwards. I have said this so much it's like...
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Anthony Lamb

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Re: What the other guys are doing with scopes
Reply #4 - Oct 18^th, 2016 at 2:13am

autosparky wrote on Oct 17^th, 2016 at 1:13am:

RPM is calculated from crank angle sensor, then they use another math channel to look at either RPM ripple or the crank angle ripple wave slopes rising and falling of each cylinder to show each cylinder contribution. It looks a bit like a relative compression current test

You could easily just put a pressure transducer in one cylinder and use a amp clamp on positive or negative battery cables and crank it over, then make a math channel with how many amps vs PSI you have.
Then you have a pretty good idea what pressure each cylinder is at without pulling the other spark or glow plus out.

Rpm math channel as stated above works pretty well even on something with 24 teeth.

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autosparky

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Re: What the other guys are doing with scopes
Reply #5 - Oct 19^th, 2016 at 2:31am

OK here's the article

Anthony Lamb wrote on Oct 18^th, 2016 at 2:13am:

autosparky wrote on Oct 17^th, 2016 at 1:13am:

RPM is calculated from crank angle sensor, then they use another math channel to look at either RPM ripple or the crank angle ripple wave slopes rising and falling of each cylinder to show each cylinder contribution. It looks a bit like a relative compression current test

You could easily just put a pressure transducer in one cylinder and use a amp clamp on positive or negative battery cables and crank it over, then make a math channel with how many amps vs PSI you have.
Then you have a pretty good idea what pressure each cylinder is at without pulling the other spark or glow plus out.

Rpm math channel as stated above works pretty well even on something with 24 teeth.

Aahh! But this is a engine running test, read the article and give as your thoughts

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Terrible_Transit_v1.pdf (1014 KB | )

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autosparky Super Nerd Picogroup Offline blind worker Posts: 2,537 Porirua New Zealand Gender:	Re: What the other guys are doing with scopes Reply #6 - Oct 27^th, 2016 at 11:30pm here's another article, see what you you think of the way these guys are diagnosing misfire
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Wigan Freshman Member Offline I'm an Autonerd Posts: 45 Wellington New Zealand Gender:	Re: What the other guys are doing with scopes Reply #7 - Oct 29^th, 2016 at 12:34pm I think you uploaded the wrong page.
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autosparky Super Nerd Picogroup Offline blind worker Posts: 2,537 Porirua New Zealand Gender:	Re: What the other guys are doing with scopes Reply #8 - Oct 29^th, 2016 at 10:37pm oops, I'll try that again
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haydenw

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Re: What the other guys are doing with scopes
Reply #9 - Oct 30^th, 2016 at 12:01am

Hi Autosparky,

Herbert and Peter use the term Delta N for crankshaft acceleration and decel to help find missfires and for piston location reference. As far as im aware they have made up the term "Delta N". Its just our normal math calculation for crankshaft speed but the tiepie software interpolates the missing tooth so its real nice to interpret the data on the screen.

Hayden

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Tom Roberts Autonerdz Administrator Picogroup Offline Autonerdz Founder Posts: 8,598 Olympia Washington USA Gender:	Re: What the other guys are doing with scopes Reply #10 - Oct 30^th, 2016 at 6:53am haydenw wrote on Oct 30^th, 2016 at 12:01am: software interpolates the missing tooth so its real nice to interpret the data on the screen. That's what the PicoScope crank math channel function does.
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