COP probe and COP extension wires

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COP probe and COP extension wires

Post by GRUSS » Sun Mar 04, 2012 7:16 pm

Can a COP probe be used on a cartridge style pack (vauxhall) or am I better off removing the pack then fitting the 4 extension leads and using the secondary pick ups?

I've read that the COP probe has limitations on certain manufacturers COP's as there shielded so a proper signal can't be obtained..

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Re: COP probe and COP extension wires

Post by Alan » Tue Mar 06, 2012 5:00 am


I would try the COP probe first - on some cartridge style packs you can get decent secondary patterns by holding the COP probe over the internal coils. If the signal is too small use the mV COP setting in the presets.

The COP extension route is the "proper" way of doing it, but takes longer to set up. Consider checking primary current before doing this in case the problem you are looking for shows up with this test?

James Tech Topics
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Re: COP probe and COP extension wires

Post by James Tech Topics » Thu Mar 08, 2012 12:42 pm

Hi Russ

The test to perform will depend on the type of the coil (integrated amplifier or not). In all cases you can lift the coil pack and use the plug extensions, but this may not be the quickest way. Either primary current (both types of coil) or primary voltage (non integrated amplifier) can show up issues with the ignition system, and the influences on the ignition of other issues. The key performance indicator is sparkline voltage and spark duration. A comparison of both (using voltage or current) will point you to the cylinder(s) in trouble.

You can do a primary current parade (using a cylinder reference trigger such as an injector) or superimposed (where all primary current ramps will appear on after the other at the same point on the screen)is using a simple edge trigger as long as you clamp the common supply. Primary and secondary issues will show up in the current waveform if you choose this method, but you may need to zoom in after the vertical drop at the end of the ramp, as this is where the secondary issues appear (and where you can look at spark duration). The spark line voltage is less easy to analyse when you're new to scopes using the current clamp when compared to seeing the ignition primary voltage.

We have used this current ramp technique successfully, on Toyota coils for instance, where there is no raw primary voltage (due to the integrated amp) and the coils are shielded fairly well rendering the COP method redundant. In my view primary V and A are great if possible, but A is good (and it may be the only nonintrusive option).

The misfire/hesitation sympton which can lead you to need to perform this test can be cause by primary issues (supply, control or physical primary winding issues), secondary issues (plugs, connecting 'wire' or secondary windings) as well as a host of other things (injection/fuel system, engine physical, event timing etc.).

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Re: COP probe and COP extension wires

Post by Lee » Sun Mar 11, 2012 1:27 pm

Hi Gruss

Have you seen the 'Muti Cop' section within the PicoScope Software. I built this when i was at Pico using the 2.2 Vauxhall Vectra which has the SAAB 9.3 Variant Engine hence the Cartridge Type Coil Pack.

If you get stuck drop me an email as i still have the 2.2 Vectra available so i can help with with waveforms set up etc should you need it. If you drop me your email address I can send you over the waveforms of the triggers etc.

Kind Regards

Lee :D

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