I recently bought a v-pro thinking i could use it for quicker secondary ignition diagnosis. The problem is when using single cyl. with eetm306a02 and eeta309a05a, the spark line is pretty much useless. I have tried different time adjustments with no help. waveform seems to be good when using ford cop adapter.
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Are you using the rpm pick-up? The secondary waveforms on my Pro are outstanding. I can watch the spark line oscillate up or down or remain flat, which can be a good diagnostic aid.If you can't explain it simply, you don't understand it well enough.
Albert Einstein -
I've tried it with and without the rpm pickup. The spark line is always almost on the ground line as if it were 0 kv. Also the duration cannot be seen.Comment
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What vehicle are you seeing this on?
What you describe sounds very similar to what you might see on a GM pickup with a 4.8, 5.3, or 6.0 that uses the coils with the laminated core visible.
If that is the case, try going to a lower kv scale and look for a small deflection in the pattern about .75ms -1.5ms after the firing. It's typically visible but very small and represents the end of the spark. If you can pick that point out, you can compare the duration on each cylinder looking for something that stands out.
These trucks used 2 different coils but always 8 of the same ones on each. The ones equipped with the molded coil provide a more conventional looking waveform that is more useful for diagnosis.Comment
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It's that way on any vehicle when i have the scope on single cyl. ignition.
Today i used it on a 1996 honda accord 2.7. This car has an external coil.
when connecting to coil wire and no. one wire and scope set to parade the pattern is good. this is ok as long as i have a coil wire. The problem is when i want to look at cylinders one at a time on a car such as a gm 3.4, my understanding is that i need to go to single cyl. ignition selection. this is where my waveform is useless. May be i'm not making the correct selections.Comment
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This should be a waste spark ignition and it does take a bit more playing with the settings but you should be able to see a usable waveform. You will see alternating power and waste firings on each cylinder's plug wire. Half will be negative firing (Invert On), and half will be positive firing (Set Invert off to display firings going in the positive direction). If you want to start with a wide view, select 100 ms and trigger at about 6 kv. this should display the power firing at the trigger point and the waste firing farther to the right.
For a closer view, switch to 5 or 10 ms. At ths point you may only see the power firing because the trigger may be set above the level of the waste firing unless there is a fault causing the waste firing to be high. You could set the trigger to Cylinder and connect the trigger lead to the same wire the secondary pickup is on, then you won't have to set the trigger level.
You could also freeze the scope and then review the data instead of looking at it live. The waveform can jump around a fair amount but you should be able to obtain a usable waveform. If you are still having trouble, verify the secondary lead isn't shorted between the signal and ground. It's unlikely if you are getting good patterns on distributor systems, but is worth a check.Comment
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Thanks to all replies. I will try these suggestions.Comment
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