testing rpm guage

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glenn
OneWave
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Posts: 21
Joined: Mon Jul 02, 2012 7:59 pm

testing rpm guage

Post by glenn » Wed Jan 03, 2018 11:16 am

hi
trying check an rpm gauge, forgive my ignorance here I don't really scope much using the pico I cant find out how to test for a signal, any help will be greatly appreciated, vehicle is a AC cobra V8 carb electronic ignition

thanks in advance

Glenn

glenn
OneWave
OneWave
Posts: 21
Joined: Mon Jul 02, 2012 7:59 pm

Re: testing rpm guage

Post by glenn » Sat Jan 06, 2018 9:22 pm

Well I guess as there's no replies this could be a stupid question :oops:
sorry I asked
:shock:

Steve Smith
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Joined: Sun Aug 25, 2013 7:22 am

Re: testing rpm guage

Post by Steve Smith » Mon Jan 08, 2018 7:39 am

Hello Glenn and thank you for the post.

Sorry for the late reply and there are no stupid questions for sure.

I think from a stability point of view I would try the current ramp of the ignition primary circuit.

Could you follow this Guided Test for connection?
https://www.picoauto.com/library/automo ... y-current/

Could you then amend the time frame to 100 ms/div, number of samples to 1 MS and apply a low pass filter of 20 kHz. Sorry I know that sounds like a lot when new to Pico but it will help. See image below:
FORUM POST IGN.jpg
Set up
Could you then capture this data with the engine at varying engine speeds (e.g. Idle, 2000 rpm, 3000 rpm etc whilst returning to idle)

Could you then post your captured data here? Just a couple of waveform buffers would be enough and I will create a Math Channel to graph the RPM

A Math Channel is created post capture utilizing the captured waveform to formulate pretty much anything.

I will then re-post your captured data with the Math Channel applied graphing your RPM.
I will also include the formula so you can create or utilize this Math Channel in other captures

Sorry Glenn one quick question, How many Cylinders does your Cobra have (I am sure that's a stupid question form me)

I hope this helps, take care......Steve

glenn
OneWave
OneWave
Posts: 21
Joined: Mon Jul 02, 2012 7:59 pm

Re: testing rpm guage

Post by glenn » Mon Jan 08, 2018 7:38 pm

Hi Steve
Thank you so much for your reply, as you say there's no such thing as a stupid question its a V8 :D , at the moment the vehicle is stripped down waiting for a clutch kit, but when up and running I'll carry out what you suggest .

thanks again

Glenn

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