Ignition coil dwell service?

ToyotaHubs
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Ignition coil dwell service?

Postby ToyotaHubs » Thu May 30, 2019 3:40 am

I do not have equipment to find proper dwell settings on ignition coils I wish to use, is there a company/tuner with service that I can send one off to?

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HaltechMatthew
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Re: Ignition coil dwell service?

Postby HaltechMatthew » Thu May 30, 2019 10:24 am

Buy a cheap DC Current Clamp and USB Scope. Cheaper than paying someone to do it and takes literally seconds to find the values.
Look for a Hantek model, as they are very common and cheap, and work well.

ToyotaHubs
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Re: Ignition coil dwell service?

Postby ToyotaHubs » Thu May 30, 2019 1:21 pm

Thanks, but I still don't know how to go about it. I've watched YT videos on it, but their setup is so confusing with wires running everywhere and seems to use much more equipment.
Would you mind breaking it down? I already have a power source. I thought I needed something to simulate firing rpm.
Suggestion for your next video :wink:

edit:
What minimum MHz would you suggest for the usb scope?

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HaltechMatthew
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Re: Ignition coil dwell service?

Postby HaltechMatthew » Thu May 30, 2019 2:18 pm

You are trying to read the current that the coils draws so to do this place the clamp over the positive wire going to the coil. Connect it to the scope.
With the engine running, on the scope you will see a triangular shark-fin pattern. In most instances you will be adjusting the dwell time until the current peaks (highest tip). If you go too far the current will hold at that amount leaving a small horizontal line before firing the spark and pretty much charging any longer than where it reaches its peak only results in more heat and no more spark. Reducing the dwell time any more will give less spark. In fact to start with try reducing the charge time and note the change you see on the scope, and then start to increase until you see it peak.

But just keep in mind that this is an area-under-the-curve thing. Doubling the dwell time does not give double the area under the curve, in other words not double the energy. So when you are dialing it in you dont need to squeeze every last 0.1ms, just back it off slightly and you will never know the difference.

Just a note, but on some coils you will see the current laying over and then if you add more charge time the current curves much higher and does not flatten out. This is also bad and you need to back off the charge time to where it is flattening off in a normal direction.

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HaltechMatthew
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Re: Ignition coil dwell service?

Postby HaltechMatthew » Thu May 30, 2019 2:22 pm

The above may sound complicated but will make sense with the equipment in hand. As mentioned it is cheap to acquire and will take the guesswork out of any future work you perform. You also get to know the real values and not something you read on a the internet from some guy who guessed it.

ToyotaHubs
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Re: Ignition coil dwell service?

Postby ToyotaHubs » Thu May 30, 2019 3:19 pm

Ok, I'm going to do it! Thanks for the encouragement, I enjoy learning new things.

ToyotaHubs
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Re: Ignition coil dwell service?

Postby ToyotaHubs » Thu May 30, 2019 3:46 pm

Will this combination work?
PicoScope 2204A
http://www.amazon.com/dp/B00GZMRZ3M
Hantek CC-65
http://www.amazon.com/dp/B06W2KFZLW

I'm under the impression Pico is a top brand (or at least people prefer their software) and this model is not expensive; this link leaves me with the impression that it will work
https://youtu.be/n7IGce393FA

Is 10MHz OK or should I step up to 25MHz Pico 2205A, and if so why?
http://www.amazon.com/dp/B0153KF4FW

ToyotaHubs
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Re: Ignition coil dwell service?

Postby ToyotaHubs » Thu May 30, 2019 3:52 pm

Would it be better to clamp the COP power wire or jump with something like a Hantek HT308 and take the signal from there?
Reading the manufacturer website this product is for taking secondary measurements. Does it matter if taking measurements of primary or secondary? Will give same waveform?

edit:
I'm reading more now and see this is for something different

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HaltechMatthew
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Re: Ignition coil dwell service?

Postby HaltechMatthew » Fri May 31, 2019 9:52 am

10Mhz will be fine. And yes both of those products will do the job well.

ToyotaHubs
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Re: Ignition coil dwell service?

Postby ToyotaHubs » Fri May 31, 2019 5:03 pm

So now I'm thinking, how do I fill the table? I will get accurate info at idle voltage but what about the other voltages, such as cranking voltage? Could I substitute the power wire on the connector with a power supply, and if so I'm assuming constant voltage setting?

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Re: Ignition coil dwell service?

Postby ToyotaHubs » Sun Jun 02, 2019 3:08 pm

HaltechMatthew wrote:10Mhz will be fine. And yes both of those products will do the job well.

Do I need an Attenuator?

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Re: Ignition coil dwell service?

Postby JimKden » Sun Jun 02, 2019 11:02 pm

It's my understanding to clamp the supply (primary) power and measure the current. The high tension side ( Hantek HT308 ) is of no info for coil dwell.
If I have some luck, my checking might yield some info that I need too.

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HaltechMatthew
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Re: Ignition coil dwell service?

Postby HaltechMatthew » Mon Jun 03, 2019 1:05 pm

If you use a power supply be sure it can supply enough current so as not to influence the result. Most will not work, you need a battery to help with a normal current draw.

In the end if you dwell time is fractionally off at voltages you never use it just plain does not matter. Test with the engine running at 14V, and test again with the alternator not working at 12V. From that extrapolate out the rest. You can also disable injectors and test at around 8 to 10V during cranking if you want to test further. But in all honesty if dwell time at 8V is something you need to get right I can guarantee you have much bigger problems to address.

It is more important at 14V to get it right. Like if you have 1.8ms in the table when it really needed 5.0ms this makes a difference. Otherwise move on to bigger tuning issues.

ToyotaHubs
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Re: Ignition coil dwell service?

Postby ToyotaHubs » Tue Jun 04, 2019 1:30 pm

OK I didn't realize the amps would affect the numbers, my current power supply max out at 5 amps.
Thank you sir.


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