The Stovebolt Site Forums The Shop Area The Electrical Bay ignition problem..grrrr

this is a 351m V6. I have power to both side of the coil, to the arm of the points and can arc the points manually with a stab light. the problem is i'm not getting power out of the coil for some reason.

I changed coils...same thing happened.

this has got to be something simple.

Electricly challenged in Washington,

Travis Weedman

travis. what is the point gap set at?

travis. when you open the points manually the coil should fire.

Does the points open and close when you turn the engine over?

One other thing, your coil should not be real hot.
You should be able to keep your hand on it.

Greg, Thank you for the reply to my question. The gap is close to .035 i'm pretty sure. it does open and close while turning the engine over. When arcing the points manually...it should send a charge out the coil ??? testing this with a light tester? no, the coil isn't hot to the touch.

Jolly from 6066 sent this answer:

You should only have power to one side, the other side is grounded
through the points. If for some reason the wire is broken between the
coil & the points, then it will give you this problem.

Michael "Jolly" Goodfellow

I already told you this:
You should only have power to one side, the other side is grounded through the points. If for some reason the wire is broken between the coil & the points, then it will give you this problem.

Let me tell you how the system works, you really need to know this so you can find the problem. Power comes to the + side of the coil from the key switch, then it runs through the winding inside the coil and back out the - side, to the dist. base, and then to the points, then to ground. With the points closed, the winding in the coil built up a "field", then when the points open, the field collapses, making a high voltage spike then travels out the high voltage wire to the cap, then across the rotor to the plugs. The condenser is there to help keep the points from burning out. If you have the key one, with the cap off, & the points closed, the coil will get hot, and really hot if left on for vary long. If you take a spark plug and put in on the high voltage coil wire, then set it on the block, open the points and you should get a spark. If not then you got troubles like above, with the bad wire. You will show power on both sides of the coil if the points are open, as there is no ground, but if they are closed, then there is an open some were between your coil and dist.

Does that help???

Jolly, I wasnt sure about the points being open and power to both sides that is why I didnt say anything. but I thought it was the other way around.(points closed = power on both sides to coil) I will check this on tuesday.

Travis, the points gap should be .017. Plugs are .035.

Jolly, I did some checking on my coil and points and you are right, power was on both sides when points were open.

Do you know why power would show on both sides when the points are open? Because the circuit is open and the voltage is just there waiting for some thing to do. Once you ground or close the points, the coil makes a load on the circuit using up the voltage and it will not show anything left on the - side as it is just a ground for the coil at this point.

I finally figured out what was wrong with this ignition. and , thanks to all of you who put in your two cents worth.

The point gap was WAAAAY to big, I pulled the distributor to check the wire from the neg side of the coil..that was fine. I had a guy help me get it back to tdc on N0.1 to make sure the dist was put back in correctly. he very quickly figured out that the wire on the cap were one position off...( I got the truck in the condition) he set the wires correctly, I set the points with a matchbook cover and BOOM.

I'ts a thing of beauty to see this 351 mag engine fire up. of course it coughed and belched up a bunch of smoke after sitting for over a year.

The lifters are a bit noisey but i'll wait til it gets to it's new home before tuning it.

happy in Washington,

glad you got it fixed...........nothing better then a purring engine,,well almost