PicoScope 7 Automotive
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Corsa C 1.2 Misfire scope
Corsa C 1.2 Misfire scope
Hi guys hope you can help, am new to scope here and still trying to learn!
Ive got a 2001 Vauxhall corsa in for a misfire, has codes for random misfire, we all know it is going to be the coil pack and a set of plugs to cure it but I wanted to prove it and what better way to spend bank holiday monday!
Im a little rusty on auto electrics hence doing some research as I want to make my scope my go to tool after my scanner.
Ive pulled a wiring diagram which I have attatched
I just wanted to clarify that I need to scope wires 15, 32, 16, 31 on the coil, these will be my 4 wires that I should get a feedback from ? any help gratefully recieved, apoligies if it is a bit of a newbie post but willing to learn here!!!
Thanks
Thanks
Ive got a 2001 Vauxhall corsa in for a misfire, has codes for random misfire, we all know it is going to be the coil pack and a set of plugs to cure it but I wanted to prove it and what better way to spend bank holiday monday!
Im a little rusty on auto electrics hence doing some research as I want to make my scope my go to tool after my scanner.
Ive pulled a wiring diagram which I have attatched
I just wanted to clarify that I need to scope wires 15, 32, 16, 31 on the coil, these will be my 4 wires that I should get a feedback from ? any help gratefully recieved, apoligies if it is a bit of a newbie post but willing to learn here!!!
Thanks
Thanks
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Steve Smith
- Pico Staff Member
- Posts: 1593
- Joined: Sun Aug 25, 2013 7:22 am
Re: Corsa C 1.2 Misfire scope
Hello and thank you for the post
Please don't apologize for being new to Pico, its great you are using the tool and aim to make this your diagnostics approach post vehicle scan, thank you
Looking at the diagram, it would appear we have the PCM either signaling the coil pack (on/off) controlling the primary dwell period inside the coil pack (T1) or the PCM switches the coil pack to ground via the internal electronics (i.e. the full primary current and induced voltage passes via the PCM)
If the latter, then attenuation will be required for the four scope channels you connect to pins 15, 32, 16 & 31
Your Guided Tests (GT) within the PicoScope software will help you here:
Please find the GT to measure primary ignition for Channel A which you can repeat for all other channels
https://www.picoauto.com/library/automo ... y-voltage/
Alternatively, you could measure the current flow though all primary winding with one channel using a current clamp place around the cable travelling to terminal 2 of T1 https://www.picoauto.com/library/automo ... y-current/
Another option could be to measure the secondary ignition event with our COP probe placed at strategic points along the coil pack (T1) or, follow the GT below using our HT extension lead and secondary ignition pick ups https://www.picoauto.com/library/automo ... cylinders/
I hope the above helps, take care......Steve
Please don't apologize for being new to Pico, its great you are using the tool and aim to make this your diagnostics approach post vehicle scan, thank you
Looking at the diagram, it would appear we have the PCM either signaling the coil pack (on/off) controlling the primary dwell period inside the coil pack (T1) or the PCM switches the coil pack to ground via the internal electronics (i.e. the full primary current and induced voltage passes via the PCM)
If the latter, then attenuation will be required for the four scope channels you connect to pins 15, 32, 16 & 31
Your Guided Tests (GT) within the PicoScope software will help you here:
Please find the GT to measure primary ignition for Channel A which you can repeat for all other channels
https://www.picoauto.com/library/automo ... y-voltage/
Alternatively, you could measure the current flow though all primary winding with one channel using a current clamp place around the cable travelling to terminal 2 of T1 https://www.picoauto.com/library/automo ... y-current/
Another option could be to measure the secondary ignition event with our COP probe placed at strategic points along the coil pack (T1) or, follow the GT below using our HT extension lead and secondary ignition pick ups https://www.picoauto.com/library/automo ... cylinders/
I hope the above helps, take care......Steve
Re: Corsa C 1.2 Misfire scope
Bad maf would do the same problem. What about getting some basic fuel trims short term and long term? A visual on the spark plugs? Maintenance history known? Fuel filter still genuine from factory, yes, I’ve seen this on same age same car as yours. Chain rattle timing off known issue.
Re: Corsa C 1.2 Misfire scope
Sorry guys have only just seen these replies..... So I will do some more digging but this I checked for relative compression and found we had a dead cylinder according to the pico! I checked the coil pack for resistance and all came up fine
I did what I thought was right at the time and I scoped the signal wire to each coil wire but unsure what I captured!
I will try and upload the capture from the coils, It says file too large each time!
Appreciate the replies, looks like I have some reading to do!!!
Thanks Guys
I did what I thought was right at the time and I scoped the signal wire to each coil wire but unsure what I captured!
I will try and upload the capture from the coils, It says file too large each time!
Appreciate the replies, looks like I have some reading to do!!!
Thanks Guys
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Re: Corsa C 1.2 Misfire scope
Disable ignition, put a channel voltage AC coupling on battery scale 5v or so, try, timebase 1s per division or 500ms, pedal to the metal, crank to capture 5s or so. You should see if one cyl does not drop the voltage on the battery. But probably its time to take the valve cover off. Few bolts here and there.