Hello all, I have a 76 f100 the po put a 460 in. I posted before I wasn’t getting power to the ignition. I found the problem but, I am getting power to the coil but no spark. It has the Mallory 29440. I changed the pick up in the dist with the cap and rotor, no change. I put the old pickup back in. Any ideas, l will test the coil again but here is another question

I have a two regulators, one was burned and I think it may be from a hot wire from the regulator. Okay this wire goes down to the fuse box, but it isn’t connected to anything. I Think is was connected to a fuse because there is a ground wire with it connected to a ground. So if this wire was connected to a fuse, would it to be a hot always or only with key on? I put on a new regulator and connector and wired as the PO had it,

the truck was parked 20 years and I got it running. Replaced heads timing chain etc. ran great started a few times and then all of a sudden no start. Going crazy. Any ideas please, thnx

 

When you changed the pick up or put the old pick up back in the distributor did you check the gap to the reluctor to make sure it is within spec. ?

 

Thank you for replying. I didn’t know there was an adjustment. I thought it was solid n read through light. How do I do that
It was running. I also replaced the ignition switch but the problem was prior to that as well

 

I would check your Dura Spark ignition module.
Your coil has a .6 ohm primary resistance.
https://www.summitracing.com/parts/maa-29440
On page 4 of the installation instructions, the Mallory coil connects directly to the horse shoe connector.

The Mallory coil is about half the resistance of what a stock coil is.The result is higher current flow through the coil and dura spark 2 ignition module.
The coil is also getting a lower voltage than a stock coil, this is because the resistor wire is about twice the resistance of the Mallory coil. In a series circuit, the voltage drop across resistors is proportional to the resistance. So about 2/3 of the applied voltage is dropped before it gets to the coil. Coils are a step up transformer, so lower the primary voltage is not a good thing.

The higher current flow in the primary ignition circuit put a extra strain on the stock ignition module, causing failure of the module.

In my opinion, hot coils are not worth the decrease reliability issues. If you do choose to use a hot coil, be sure to carry a spare ignition module.

Jim

 

Even if all stock, it's not a bad idea. I carry both mine upside-down in a zip lock baggie ... in a box.​​​​​​​

 

thank you for the reply. I will need to review your post a few times to digest, I you tubed Mallory coils n performed the tests. The coil and the dist module check right on specs.

One note when I removed the original dist cap the center tip was gone. When it was running I could hear a squeal when reving it up. I’m wondering if the missing piece could be inside causing an issue.

I’m just lost. Thinking of taking the dist out and apart. What I’d like to do is put it all back to stock, but for now I just want to get it running so I can move onto the drivetrain. Once it’s road worthy I’ll put in harness n update all electrical.

so far everything leads to the distributor.

still wondering about the red wire from the regulator going to the fuse box. Is that how the regulator gets its power? If so power all the time or key on. I had to replace the regulator because it burned up n I think I connected that wire ti a always hot fuse.
thnx again.

 

This should be useful in the discussion and any pics you can post of the engine bay and your current set up.

 

 

This is the red wire coming from the regulator to the fuse box. I’m assuming it gets connected to a hot fuse. If so hot always or when key is on.

 

the red wire in the photo looks like it’s connected to the orange but it’s not, it’s connected to the green. Also I’m assuming the red wire from the regulator does not need to be connected to get spark, is that correct?

 

Nice pics. They'll be helpful. In looking things over. I noticed first what I marked in the pic below. I'll look further in a bit. Headed to town.

After posting the pic I see the print in the color I used is hardly legible.

1) The wires in box one all need to be fused protected if not already. The black wire and the two heavy gauge wires have some
real potential energy if they go to ground being that close to the battery. The fuses need to be sized to the gauge wire you're using.

2) Box 2 you need to slip some heat shrink over that area where the bare wire is visible. It will wick moisture down the wire causing
it to corrode and degrade the capacity of the wire significantly in a rather short time. Heat shrink and it's good for a long time.

 

Sorry for all the double picks, I obviously did something wrong. So I contacted Mallory support, the guy was kind of a jerk, but anyway, he said I should replace the coil. I went back onto their web site to check the trouble shooting again, this time I noticed the guy say the center brown wire coming from the coil should be grounded to the engine. well the brown green and red wires going to the pin connector in the pic are coming from the coil, the truck ran like this. Not unless the PO did something with the wiring to change things, above my wheelhouse.

So I called Mallory back and you guessed it, I got the same happy guy. I told him about the brown wire in the video, he said it should be grounded after the connector or I won't get spark. even after telling him the truck ran without it being grounded, he insisted it be grounded. So I cut the wire and put it to a ground and nothing, same thing.

I ordered a new Mallory for now, hopefully that's the problem. easy for now so I can get it running. I will replace all the wiring. Thanks for letting me know about the issues with the wires, eventually I will be replacing all the wiring and properly sealing them.

So if anyone has any other ideas regarding the no spark between now and getting the new coil please let me know.

regarding the wire coming from the regulator to the fuse box, any ideas or thoughts. IMO it had to go to a fuse, nothing else down there to connect to unless I have missed something. I the mean time I removed the cluster panel and replaced the electrical panel and light sockets. had to take it out to see ignition wires.

BTW speaking of ignition wires I am pretty certain I wired it correctly when I replaced it, it cranks when I turn to start. so i reversed the two wires on the starter solenoid to see, in doing so, when I turned the key just to ON it started to crank. So i reversed the wires back, just curious on that.

I apologize for being all of the placed, just frustrated.

 

Trouble shooting electrical after someone else (previous owner) has put their own unique spin on things. Any part of the electrical harness can be duplicated with the original terminations or it can be upgraded to more modern connectors that are waterproof especially in the engine bay. Electrical is about the hardest thing to do on these trucks IMHO especially if you're on a deadline where the chances of inadvertently making a mistake go up significantly. If you can block out any preconceived finishing dates and take your time and enjoy working on a fifty year old classic. Don;t put yourself under any undo pressure, there's plenty of it out there from other things. Let your garage be your sanctuary or you won't be inspired to get out there. Just know that there's plenty of folks on this forum more than happy to answer any questions you have and point you in the right direction.
Any further questions or progress post back. Wish you the best.

 

Thnx, not in a hurry, I have been working on this for 1-year now. I did a lot to it and had to park it for a few months to get other things done around the house, living on 2-acres requires time. I am fortunate to have a 2500 SF (sanctuary shop), to work in just outside my back door. Only reason for wanting to get it running, is so I can easily pull it in and out the shop with the snow hitting us. I'm, retired so everyday is a Saturday except Sunday. Thanks for the word of inspiration.

Do you have any thoughts on the red wire from the regulator to the fuse box. is that supposed to be connected to hot?

 

I see you have a Mallory Unilite distributor, I worked at Super Shops back in the day and we sold Mallory products. The Unilite module is a good design and very accurate, but if you have a bad ground you will kill the module and it will make you a pedestrian. Also don't try to disconnect the battery while the engine is running because that will also kill the module. I don't know of a way for you to check to see if the module is bad, at Super Shops we had a ignition system on the counter and we could connect the customers distributor or coil and determine what needed replacing. Unfortunately I have replaced a lot of these Unilite modules for customers.

Brian