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  #11  
Old July 6th, 2017, 08:53 PM
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Quote:
Originally Posted by jeepdan View Post
It might not be the coil.
And he probably did sell you a coil that was new, and in working order.
It's just that many of them appear to fail in a short time of use.

I wish that I lived closer to you, I would be glad to help you trouble shoot the gremlin.
I appreciate that very much. I'm not sure what to do next. Electrical is definitely not my strong suit. I'll keep asking and researching. The worst part for me is wondering, if I get the truck started, will it only be temporary and happen again when I'm out with it.
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  #12  
Old July 6th, 2017, 09:43 PM
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Sorry to take so long to respond. Been really busy,working here and we are 14 hours ahead so it's day here; night where you are.

The ignition is rather straightforward in an M715. Wire #12 comes from the ignition switch on the dash panel. When you turn it "on", you supply 24V to the wire on the side of the ignitor. You should be able to see 24Volts on that wire (reference to ground) when the switch is on. If not, you need to see where it is getting interrupted. For instance, is there a hidden "Kill" switch between the ignition switch and the ignitor? If the correct voltage is being supplied, then we have an internal issue in the ignitor. Unlike many American cars, there is no ballast resistor on the firewall and no ballast resistor bypass set of contacts on the starter button.

What that did was to give full 12 volts to a coil when starting. Then when the key was released, the 12 volts would have to go through a ballast resistor when in the "Run" position, supplying about 8Volts (talking a 12volt sustem of course). Our trucks originally had a ballast resistor but it was eliminated. We have no ballast bypass contacts.

Clear as mud yet?

It would be possibpe to take that large blank metal plug out of the ignitor and connect a wire to it to monitor the voltage as you drive.
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  #13  
Old July 7th, 2017, 04:26 AM
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Clear as mud to me, but I figured the first thing I needed to do was check for 24 volts going to the ignitor. Where would I get that reading under the cap?
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  #14  
Old July 7th, 2017, 04:47 AM
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Quote:
Originally Posted by militarypotts View Post
Clear as mud to me, but I figured the first thing I needed to do was check for 24 volts going to the ignitor. Where would I get that reading under the cap?
Just unscrew the wire/connector that screws into the side of the ignitor and check the center pin of the connector. That is the 24 Volt feed. In the online -20 manual, Chapter 2, Section 14, Figure 2-29 Ignitor, it is number 2 in the illustration.

You shouldn't have to take the cap off.
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Old July 7th, 2017, 08:58 PM
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Thanks Don, I will try to get around to that this weekend. Ignition switch in the on position. Does someone need to hit the starter switch while I'm checking the reading?
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  #16  
Old July 7th, 2017, 10:11 PM
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Just a thought here. Should, I get a 24 volt reading at the ignitor, what would be my next step? Also, when installing a Pertronic's in the ignitor, is their any special way the magnetic collar slips over the distributor shaft? I did it gently and made sure it was all the way down as far as it would go. I feel I installed everything correctly because my truck fired up immediately upon putting it all back together.
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  #17  
Old July 7th, 2017, 10:23 PM
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Ignition switch "ON", no need to step on the starter because this circuit is very basic, unlike most automotive circuits.

As for the Pertronix system, unfortunately I don't have any experience with one so I will yield to another member who has experience with one. Not saying that they are a problem. Probably much more reliable in the long ru..
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  #18  
Old July 8th, 2017, 07:59 AM
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You know Don, I could always switch it back to points and a condenser, but I've heard such positive reviews on the Pertonix system. I think my problem lies within the coil I'm sorry to say. Not sure what the seller of it is going to say or do about it though. Literally got 3 starts out of a supposedly new coil.
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  #19  
Old July 8th, 2017, 08:17 AM
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As I've said before my "new" china coil lasted about 2 miles. Once they cool down, they will usually work again till hot. That being said, no way to test them unless you heat it up. The US NOS coils are now very hard to find.

Going back to points will not change the operation of the coil. I'm sure the electronic system you installed heats the coil just the same. I always thought those electronic systems had their own special coils but I now assume not.
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  #20  
Old July 8th, 2017, 10:03 AM
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The Pertronix collar should index to a notch on the distributor shaft. Mine did, and every distributor (ignitor, etc.) I've ever seen has had some similar feature to index the rotor.
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