Hey Jackiejoy. Did you get this moved or start another one in the appropriate forum section? This is for the 67 to 72 trucks, and no such sensors or automatic locks existed back then. Sounds like you’re in the mid 80s and up category.
good luck!

 

Hello everyone, I need some help figuring out my ignition issue. I had a short in the ignition and needed to re wire it. I now get no spark at all from coil to distributor so I’m pretty certain it’s wiring issue. The truck will crank good but no start no spark.
can someone suggest any ideas? Also if someone can, in simple words which 3 connections to where I need on the ignition switch to “test” if it’s one of the other wires.
thanks

 

Start on the easy end first, so you don't have to crawl around under the dash right away.
With the key in the ON position, do you have power to the positive side of the ignition coil?

And what year is your truck? What engine, distributor and ignition components?

Paul

 

 

Sorry, Daniel. When I responded last night, I didn’t realize it was your truck again. There’s been a couple of others thrown in.
It looks like the yellow wire is missing from your ignition switch. It was there in your first picture, but don’t see it now.
Did you remove it? Or is it somehow connected to another wire?
The yellow wire supplies the ignition switch with power, so without it nothing‘s gonna work on the switched side of things.

 

Since you say it does crank, assuming that’s with the key, then you do have power to the ignition switch. Do you have a voltmeter or test light? Those are gonna be your friends right now.

 

hey! Yes, it got fried, and I traced it and cut it. I re wired all 3 wires (battery, solenoid and coil.)but only get a crank no spark. What am I missing? The yellow one is the battery I supposed? That’s the location on the switch

 

hey! Yes, I get power to the positive coil, and everywhere else. The S side on the starter solenoid gets power when the key is turned to start.
I’m hitting a wall.. trying to figure it out. It’s not the coil as I replaced it. And it’s not anything with the distributor as the spark doesn’t reach the coil even.
attached is an updated picture

 

A comment, for the moment. I don’t have a full handle on it yet. But isn’t that side terminal the proof out ground?
If so, those two green wires do not belong there. Those are for other things. Specifically the ignition coil and the voltage regulator.
However, since you say, the coil has power, maybe I’m wrong on which terminal that is visible from the side.

You can confirm this with a ohm meter, though, by putting a probe on that terminal and turning the key to start. If the program grounds to the outer shell of the ignition switch, that is indeed the prove out terminal.
It’s just a ground and is for the brake warning lamp and nothing else.

 

 

So, I managed to identify the issue. I get no power to the negative side of the coil when the key is on run.
i switched the wire to the distributor and got it to start. After that, lost power again. Any ideas?

 

You'll only have power to the negative side of the coil when the points are closed. That's what the points do. When points are open the ground circuit for the coil is broken/open and you won't get any readings on negative side.

When points are closed, if you took a reading at negative side you would see low voltage due to voltage drop going through coil. You could use ohms law to calculate what voltage based on the resistance of the coil. Not sure why you would want to though. As long as you are getting correct voltage at the right time to coil and your coil tests within spec for resistance readings it really doesn't matter what voltage you see on the negative side of the coil.

When you send power to the coil it starts to build a magnetic field, that field continues to build until the power is shut off (key off, or points open). When the power shuts off, the magnetic field collapses, when that occurs the collapsing magnetic field creates/induces a current in the "secondary" windings of the coil. Those are connected to the coil main output which goes to the distributor. It is the breaking of the ground circuit that gets the coil to fire, which is sent via distributor to whichever spark plug it is aimed at.

When you shut key off that induces a single spark from the coil but no more and the engine shuts down.

When the engine is running the points inside the distributor open and close in sync with the distributor terminals. With points closed, charge builds in coil, the points open, spark is sent to spark plug engine fires, points close again, charge builds, points open, spark from coil, rinse, repeat.

With key on, you should have 6-9 volts to positive side of coil, if higher or lower there may be an issue with your ballast resistor/resistor wire.

With key in start position, the resistor wire is bypassed and a full 12v is sent to coil from the starter solenoid itself.

 

correct I understand that, my issue is that even with the key in a run position, not cracking, just on, I get no voltage on the negative side. I replaced a condenser yesterday and nothing still. Would you replace the points as well?

 

Are they open or closed? I didn’t see where you said that.
Check your voltage on the negative side again and look at the points. Are they open? In that case, reading zero voltage is correct.