Why is coil hot?

[69bronco69]

I have a 69 Bronco with a stock 302 with 58k original miles. I have had a radio/cd player installed in a console I installed between the front seats. The radio is grounded to the seat mount bolt. I noticed the other day on my coil, the big gray wire on top and the black wire to the left are really warm when the radio is on without the motor running. The coil housing is really warm also. There is a red wire to the right, but it is not warm. The smaller black wire enters the bottom of the distributer housing. What would be the cause?

I have included pic of coil:

http://i1116.photobucket.com/albums/...loads/coil.jpg

thanks,

 

[Bully Bob]

"....are really warm when the radio is on without the motor running."

Assume you are turning the key to the "on" position.? If so., that energizes the ignition.

(BTW ., the pic won't come up.)

 

[69bronco69]

The key was on the ACC position. I traced the wires and they were spliced into the black wire leading from the top position of the ignition. The other wire was traced to a yellow wire leading from the fuse box. When I took the lead off the ignition, the radio kept playing while in the ACC position and motor not running. Fixed the pic link My link

 

[Rons beast]

Sounds like a wiring problem. You said you traced a wire that was spliced to a black wire from the top position of the ignition? I don't follow that. Does it look like some prior owner spliced that...not factory?

The fact that the coil and wires are getting hot indicate a "search for ground" problem which comes from a miss wireing problem.

If anyone has the exact info please let me know ,but from my memory, (which wife says is "selective"), here is what I believe the coil should have....

The red wire on the coil should have 12 volts on cranking, then have only about 5 to 7 volts when the engine is running, and no voltage in the ACC position.

If you have 12 volts when running and on ACC there is a wiring problem. This could be from where someone has done the splice you described.

The black wire is ground through the points in the dist. any other wire should be off the same "-" coil terminal and be for a Tach lead.

No other wires should be run from the coil.

If someone added wires attemption to pull power, or find a ground then the circuit is backfeeding or searching for ground through the coil.

BTW...the seat bolt is not a good ground. For a high wattage sound system run a good 8 or 10 guage wire to a ground point on the body or to the battery.

You can get a "ground point strip" at a parts store. It's a simple metal strip with a number of male spade points to make it easy to add any other wires that need a ground.

Hope this helps.

 

[69bronco69]

you traced a wire that was spliced to a black wire from the top position of the ignition? I don't follow that.

One of the radio "power" wires was spliced into the black wire. This black wire is connected to the top terminal on the back on the key ignition assembly at the dash. I assume this was done to enable the radio to come on when the key was turned ON or to ACC. All the other wiring looks to be from factory. This is the only spliced in wiring I know of under the dash. I will move the ground wire like you suggested.

One other thing I tried. While the engine was running, I quickly turned the key to ACC - the engine kept running. How would you test the ignition switch to see if it is bad? This newbie has many questions. Thanks for the help.

 

[Rons beast]

Remove that wire spliced into the ignition, and move it to a fused supply in the fuse box. There should be an extra space where you can add a fuse or get power and use an inline fuse.

Use a test light to find a spot that's "hot" with the key ON or in ACC.

Parts stores usually have the little "toys" to add a male spade post to a fuse Just be sure you put your wire on the fused side, or better yet use an inline fuse so if something in the radio fails it doesn't blow the fuse in the box.

That should correct the problem with the coil getting hot, and most likely the problem with the engine running in ACC position.

Good Luck

Let us Know the results.

 

[69bronco69]

Remove that wire spliced into the ignition, and move it to a fused supply in the fuse box. There should be an extra space where you can add a fuse or get power and use an inline fuse.

Use a test light to find a spot that's "hot" with the key ON or in ACC.

Parts stores usually have the little "toys" to add a male spade post to a fuse Just be sure you put your wire on the fused side, or better yet use an inline fuse so if something in the radio fails it doesn't blow the fuse in the box.

That should correct the problem with the coil getting hot, and most likely the problem with the engine running in ACC position.

Good Luck

Let us Know the results.

I have taken the switch out but am having trouble removing the wires. I have two pics as to my progress.

switch 1

and

http://i1116.photobucket.com/albums/k561/j7o7h7n7/utf-8BSU1HMDAyMjYtMjAxMTA3MTgtMTA0MC5qcGc.jpg

How do I get rest of wires removed to test switch? I see the wires enter the black plastic piece.

After looking at the wiring at this point I realized I gave incorrect info on where the radio was hooked up. One lead from radio goes to the back of cigarette lighter. The other to a black wire in the big bundle that heads toward fuse box. Looks to be original power wire for am radio. sorry guys for that.

When I removed the ********* wire from the back of ignition switch the radio stopped playing as shown in second pic.

You guys have been great so far. I really do appreciate your input.

 

[Rons beast]

Have you removed the wire spliced into....well wherever it is?

Are you trying to fix the coil heating problem or something else?

On wiring problems there has to be focus on one circuit and problem at a time.

 

[69bronco69]

Have you removed the wire spliced into....well wherever it is?

Are you trying to fix the coil heating problem or something else?

On wiring problems there has to be focus on one circuit and problem at a time.

Trying to fix coil heating problem. I made error on radio hookup - on lead is on back of cigarette light and other to black wire in huge bundle running to fuse box(looks to be lead from orignal AM radio)

I have some pics of wire arrangment at switch

switch 1

and

switch 2

I have two pics at coil. The first coil pics shows a green wire spliced into the red. I traced it back to the yellow wire on the stud terminal on switch. The green wire just connects the coil red wire to the yellow from stud terminal on switch. This yellow wire has been spliced to provide power to an aftermarket fuel guage mounted below dash. I think the fuel gauge would come on with the key in ACC position if i remember right.

coil 1and pic two shows where the other coil wire goes (I dont know what that is called either)

coil 2

Hope this clears up the info - thanks for being patient

 

[69bronco69]

Trying to fix coil heating problem. I made error on radio hookup - on lead is on back of cigarette light and other to black wire in huge bundle running to fuse box(looks to be lead from orignal AM radio)

I have some pics of wire arrangment at switch

switch 1

and

switch 2

I have two pics at coil. The first coil pics shows a green wire spliced into the red. I traced it back to the yellow wire on the stud terminal on switch. The green wire just connects the coil red wire to the yellow from stud terminal on switch. This yellow wire has been spliced to provide power to an aftermarket fuel guage mounted below dash. I think the fuel gauge would come on with the key in ACC position if i remember right.

coil 1and pic two shows where the other coil wire goes (I dont know what that is called either)

coil 2

Hope this clears up the info - thanks for being patient

This is what I have just done. I disconnected the green wire that connected to the red coil wire and stud terminal on back of ignition switch. I reassembled ignition switch and wires keeping the fuel gauge connected to stud terminal of ignition switch. Turned the key to ACC - radio and fuel gauge came on and coil did not get hot. I let it sit for about 10 minutes with radio playing - plenty of time for coil to get hot before. When I started the motor it fired right up, but when I let the key fall back from start to run she died. I did this a few times.

So I reconnnected the green wire and motor started right up and kept running. I got out and disconnected the green wire while it was running and she died. So, bad coil?

 

[69bronco69]

About trace the coil resistor wire under the dash. I hope that is the problem. Thanks for all the help. You guys know your stuff.

Thanks - john

 

[Seabronc]

The coil should have 12V direct when the key is in START. However when it is in the RUN position the coil should be getting its 12V through a coil resistor or the coil will get too much current. Most likely why it is overheating. See the attached diagram, it is for a Duraspark II ignition, but the method of hooking up is the same. In this system they use a resistive wire instead of a resistor but the theory is the same. You need to do the hookup the same.

Good luck,

 

[69bronco69]

The coil should have 12V direct when the key is in START. However when it is in the RUN position the coil should be getting its 12V through a coil resistor or the coil will get too much current. Most likely why it is overheating. See the attached diagram, it is for a Duraspark II ignition, but the method of hooking up is the same. In this system they use a resistive wire instead of a resistor but the theory is the same. You need to do the hookup the same.

Good luck,

I found two types of resistors; small ceramic resistor ballast and a 61" wire. Both are rated at 1.35 ohms. I understand how I could wire the smaller ballast in the red/green wire, but where would I put a 61" wire?

 

[Seabronc]

I found two types of resistors; small ceramic resistor ballast and a 61" wire. Both are rated at 1.35 ohms. I understand how I could wire the smaller ballast in the red/green wire, but where would I put a 61" wire?

You use one or the other, just as the diagram shows.

 

[69bronco69]

Problem solved! and man do I feel like an idiot.

Earlier when I was discussing the pink resistor wire, I thought it ran pink from coil to ign. I know some of you told me different, showed me diagrams and all, but on my coil terminal, I have a pink wire for about 6 inches. I also had pink wire coming from ign switch. I kept thinking I have the pink resistor wire right in front of me right here. What I did not see was, the pink wire at the coil had a white stripe. This is where the green wire was spliced in and ran to ign switch.

Under the dash, I found the "pink wire" was intact and not burned at all.

On the engine compartment there is a 3 prong quick connect plug at the firewall. Coming into the wall it has 3 wires pink w/white, white, and red. The pink wire I had been talking about was this one. I was confusing this pink wire as the resistor ignition coil wire. About 2 feet along this pink wire toward the coil it was cut and just taped off. I have no idea why. There was about 18 inches of wire missing from that point to the coil. I did not notice this taped off pink section until last night trying to run down a VR and alternator problem.

SO.... I removed the green wire from the coil pink wire splice and ign switch. Ran new wire from three prong plug at firewall to coil. Problem fixed - no hot coil on ACC position and it keeps running when key position goes from start to run.

Hopefully I saved my coil and points.

Sorry if wasted all of your time on a simple cut wire, but thanks so much

john

 

[Seabronc]

Not a problem. Thanks for reporting back on the solution.

Good luck,