How to make ignition coil pack fire

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LAV1000
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Re: How to make ignition coil pack fire

Post by LAV1000 »

wkellen wrote:A -> B =.6 ohms
C -> B =.6 ohms
B -> A =.6 ohms
B -> C =.6 ohms

I never checked across A and C. I figured they were different coil triggers, so they didn't connect at all.
That seems low to me, CDI type coil ?
wkellen
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Re: How to make ignition coil pack fire

Post by wkellen »

That sounded low to me too, but I am not sure.
billr
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Re: How to make ignition coil pack fire

Post by billr »

The rest of the schematic was posted on that other forum. It confirms that the coil pin B is 12V power. Pin A is drive for cyl. 2&3, pin C is drive for cyl. 1&4. Those pins end up as double (paralleled) pins at the stock ECU, so I think these are "dumb" coils and the ECU is simply switching coil current to ground. Alas, there seems to be an error or ambiguity where the coil assembly is shown on the scematic: it shows pin C being connect to both coil sections, I think it is pin B (the 12V power that is that way. Yes, just touching wires together to do that often results in arcing and too slow a current drop to get a spark from the coil. Many years of doing that to test the old single-coil breaker-point systems taught me that...
wkellen
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Re: How to make ignition coil pack fire

Post by wkellen »

I saw that. I am in agreement that I can't just tap the wires to ground to make them fire. I have some TIP120's just sitting around, so I am going to try to make up a quick circuit to test them out. Worst I could do is blow the transistors. Still looking for some resistors to use and test the CMP sensor. Radio Shack going out of business is killing me.
wkellen
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Re: How to make ignition coil pack fire

Post by wkellen »

Oh and thanks for all the help!
wkellen
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Re: How to make ignition coil pack fire

Post by wkellen »

A little success with the CMP sensor. I used 12v to red wire, ground to black/white wire, and a 1k ohm resistor to the signal wire from the red wire. Without metal touching, it read 11.6v between ground and signal. With metal touching, it reads 0v. Now I can read high and low states. On to the coil pack now. :-)
jsmcortina
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Re: How to make ignition coil pack fire

Post by jsmcortina »

TIP120 aren't suitable for driving coils due to the high flyback voltage.

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wkellen
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Re: How to make ignition coil pack fire

Post by wkellen »

I built a quick circuit with the TIP120. I controlled it with an old arduino uno I have. A simple little program. Set pin high to TIP120. Wait 3ms and then set pin low. Delay 1 second and repeat. Success! I tried it on both trigger wires separately and got spark on all plugs. It was a weak spark, but a spark. Now was it a weak spark because of the TIP120'S, because the 3ms wasn't long enough, or something else?
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