Pertyfly

[thrival]

pertyfly:

You seem a guy with lots of engine experience. I need to ask you a question.
Please let me direct your attention to the second ignition circuit in my project folder.
My question is this: when current is running to the coil,
exactly what component breaks the connection in the coil circuit, that
the reverse HV feedback spike reaches the plugs? I know the
distributor turns, and the HV coil primary goes to the distributor
cap, but I assume the break in the coil's power must be between the
battery and ground, not the HV wire and the distributor.

Reason: I need to use that make-&-break contact for purposes illustrated.
My truck has the coil built into the cap, no points to change or condensor
that I can see.

This question goes out to anyone else who might know.

[pertyfly]

Yeah...

The in-cap coil on those chevys definitely has no points or condenser. On the cars with points, however, these are what make and break the connection. As the points open, the coil fires.

However, on the cars with no points, it is all done electronically. There is a signal generated from a sensor on the engine which picks up the rotation of the cam/crank, and sends a signal to the ECU (computer). The computer is then the device that (based on the sensor input) makes and breaks the connection for the coil.

On some cars the sensor is the crank or cam sensor, and on others it is actually within the distributor. Mostly magnetic pickups.

On this truck specifically, I actually don't remember what type of sensor it uses. I could look it up, but it's too late right now

I'm sure someone else would know the sensor on that one.

[thrival]

Pertyfly:

Thank you very much for that information. Don't knock yourself out,
an auto parts store should be able to help me now.

[pertyfly]

Yeah, but at the same time...like I said, I mean...I believe, if I'm not mistaken........the sensor doesn't go directly to the coil, it goes through the computer first. I may be wrong, but I think this is the case (so that the computer can monitor the signal, etc. So, you should be able to just take the primary signal, and that should give you your signal. Although, again, because it is reversed, I don't know how exactly you would be able to set it up to give a longer spark. The simplest thing I can think of is to purchase a performance coil. Ebay has them for really decent prices. However, I am like you and don't like to just do that. I love building stuff, and trying to figure out how to improve it, etc. So in terms of that, I don't know exactly how you would be able to increase the spark duration, or enhance it's power.

Supposedly the coil works pretty much as an inductor. Which is why it works on the loss of power to the primary. The drop in current induces current on the secondary. So, in that thinking, I would wonder if supplying more current and/or voltage somehow would induce more current/voltage. (because there is more of a drop, since it should be proportional) Possibly putting the signal through transistors used as switches to a high voltage circuit or something. Sorry, I'm not sure if it's voltage induced, or current induced.

But yeah...I hope that helps. I have been following your posts, and projects folder. I find your ideas, and methods at going about them quite interesting.

Chris

[pertyfly]

On second thought, I believe it's current induced, not voltage....hmmm....how to increase this... *thinks*...

[thrival]

[kevinsatterfield]

[pertyfly]

[AlaskaStar]

[vapornut]