67 f100. Trying to sort out the ignition and try to crank. Won’t get reaction. I un do the alternator cable as it seems to short.
still noting. Truck does get power.

 

 

This one might be more clear with what you're dealing with

 

Eeek! That wiring makes me cringe. Please take no offense. If it were my truck I would be replacing most of that wiring. I appears there are some burn marks on what appears to be the main power feed to the ignition switch and the copper strands showing are a short waiting to happen that could lead to an electrical fire. That needs to be cleaned up for sure.

Your ignition coil appears to be wired backwards. You should be getting positive feed from the ignition switch to the positive side of the coil. The negative side of the coil connects to the points in the distributor. When the points open they break the negative side of the coil interrupting the circuit. This causes the magnetic field to collapse on the coil inducing current in the secondary windings firing the spark plug.



The coil is powered differently depending on whether the key is in "run" or "start." When you have the key in run position the coil gets power from the ignition switch through a "resistor wire" that reduces voltage to somewhere in the 7-9 volt range. During startup, the resistor wire is bypassed and power is fed to the coil from the starter solenoid itself.

From the battery side of the starter solenoid you should have a thick gauge wire that feeds power to the ignition switch (that's the wire that appears to be burnt and you can see bare copper strands). That line should have a fusable link that will melt in the event of an over current situation. A fusable link is a thinner gauge wire that will handle overload for a longer period than a fuse, but after a certain time period it will melt. You can replace that with another length of fusable link or a fuse or circuit breaker, but you need to make sure it is large enough to handle the amperage the alternator puts out.

There are two different approaches I would take here.

First one being, bypass the rats nest all together, hot wire the positive side of the coil, make sure negative side connects to the points then jump the solenoid (don't forget to take out of gear if a manual) and see if you can get the truck to fire. Doing this would at least confirm what, if any issues there may be present in the coil and distributor. If you can get it to fire that way, coil, points, cap & rotor should be good enough to continue further testing and cleaning up the wiring. After that you can further diagnose any potential issues with your ignition switch, resistor wire and the main power feed into the cab.

The other approach would be to just start fresh, cleanup all the wiring, grab a multi-meter and test all the various components. Most of the tests will be based on continuity and a few based on voltage you are seeing.

The schematics posted above will provide a great guide to re-wire what you need to.

 

Thank you so much for the detailed reply, just saw it.
so you say the ignition goes to the positive, distributer to negative on the coil.
get rid of all the exposed wires, make pig tail I assume?
and try and crank it up?
thank you! Just trying to get this thing going

 

You're welcome.

Yes, those are the obvious issues that stick out and what I would start with. If it still doesn't fire additional troubleshooting can be done.

Regarding the exposed wires, it appears there is a stud that they are wrapped around. The proper fix would be to terminate the wire or wires with a ring terminal that can be crimped to the wire and secured to the stud with a nut.

 

Eeeek…. Wiring is a PITA… I tore all mine out of my ‘67 and cleaned up the entire harness to match factory, and after that everything worked right. Took a couple of days but it was worth it!

 

so after redoing the wiring, making sure everything in place I tried starting.. no go.
i put some starter fluid in the carb and I get rattling buzzing noise from it. But no farther reaction.
any ideas?
thanks

 

Next step would be to use the schematics provided above, grab a multimeter and a lot of patience and go through each leg of the wiring harness. I would test for continuity with multimeter set to ohms.

Before testing though, I would find all the grounds and clean them up, both the ring terminal on the wire and contact surface. At a minimum you should have the following grounds:
Battery to engine block
Back of engine (intake, cylinder head or bell housing bolt) to firewall.

If there's any corrosion or a bunch of gunk at base of distributor that needs to be cleaned so the distributor has a good ground to engine block.

When testing wiring harness I'm looking for zero resistance over the length of any given wire. If there's high resistance or infinite resistance on any stretch of wire there is a break in the line somewhere that needs to be fix.

I'll also check for any continuity between wires that are bundled together, there should be infinite resistance between the wires that shouldn't be connected together.

Once you've confirmed wiring is intact, next I'm checking for voltage readings. With key in run position you should be getting 7-9 volts at the positive side of the ignition coil. As long as you're getting at least 6 volts with engine off you should be okay.

With key in start position you should get close to 12v at coil. For that test I'd disconnect the cable going to the starter from the solenoid so it doesn't crank while testing.

You'll want to inspect the points, if there's any pitting or corrosion, replace them and double check the gap regardless.

The coil can be tested but I would need to look up the specs to tell you what ohm range you should see on the primary and secondary windings. If the coil appears to have leaked oil at all I would just replace it.

All the above will take some time so I'll stop here but one final note, starter fluid is a bad idea.

The noise you described sounds like it was dieseling which is a quick way to pop a hole in the piston. The only time I ever use that stuff is to fire up an old diesel tractor on my uncles farm. For a gas engine it's more likely to damage pistons than anything else. Because of the noise you heard it might not be a bad idea to check compression on all cylinders, which isn't a bad idea regardless.

For a gas engine to run you need proper fuel/air mixture, compression and spark.


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got you. Will do.
im just a bit frustrated as I feel like I’m running into a junction where there is fuel and air in the carb, ignition clearly work. Yet no response.
how much of it make sense?

 

It's possible ignition timing is off and that might be causing the no start issue. Maybe pop #1 plug out, roll engine over by hand until you can feel with your finger that you're on the compression stroke, once you're in compression keep rolling engine over until 0* TDC mark on damper lines up with the pointer on timing cover. Pop the distributor cap and confirm the rotor is lined up with #1 plug wire. If it's off just a little make a small adjustment of the distributor to line it up.

If it's way off, I'd pull the distributor from the engine, confirm the roll pin didn't shear on the distributor gear and reseat the distributor so #1 lines up. I would then triple check firing order is correct. Don't forget on a Ford 1-4 on passenger side, 5-8 on drivers side.

If everything lines up then dive deeper into wiring harness.

If you're getting spark and fuel, it's a really good idea to check the compression.

I know how frustrating this can be, especially the electrical stuff. Be methodical, check each leg of a circuit and when you get frustrated or just need a break don't be afraid to walk away for a bit.

 

I had a 79 with a 460 that suddenly stopped running. I diagnosed for weeks, even had my son's auto shop play with it. I had fuel, spark, air. I finally pulled the engine for another I had on hand for this truck. Turns out, the nylon gears on the timing chain had turned to dust. I don't know if they used nylon gears in 1967. Good luck

 

re did some wiring today.
when I’m trying to crank the engine, it seems like the solenoid just keep buzzing and not really power the starter. I checked the solenoid and even tried a different one. I made sure wires are right, and right.
any ideas?

 

#1 = To Battery positive post
#2 = To Ignition Switch "start" terminal (activates solenoid)
#3 = Main power feed to ignition switch/fuse panel (possibly alternator charge wire)
#4 = Ignition Coil 12v+ bypass activated when key in "start" position
#5 = To starter

If #3 is the main power feed to cab, I am curious where the charge wire from the alternator is located. If that wire traces back to the voltage regulator/alternator wiring harness, where is the main power feed to the cab?

#2 should really have a ring terminal crimped on so it can be properly secured with the nut.

 

Finally got her running strong! I did let it run for a few, and it caught a little flame in the carb area. I need to make sure everything is tight. Have anyone saw those thick carb gaskets? It seems like they almost nor going to really seal anything.