Another dead coil!
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Senior User
Joined: Aug 2002
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Another dead coil!
Over the past two years, I am on the 4th ignition coil in my Bronco! For the life of me, I can't seam to put my finger on why they keep failing on me. Heck, I am to the point, I keep one with me, because I never know when it will fail!
Here is what I have checked so far...
1. Plug gap - at .42 - .44
2. All new plug wires
3. new cap & rotor
4. replaced the Duraspark ignition box with a known good one
5. checked for shorts, etc...
Any idea's? I have installed two Accel's & two stock coils. The Accel's will last about 3 months, a stock will last about 6 months.
Here is what I have checked so far...
1. Plug gap - at .42 - .44
2. All new plug wires
3. new cap & rotor
4. replaced the Duraspark ignition box with a known good one
5. checked for shorts, etc...
Any idea's? I have installed two Accel's & two stock coils. The Accel's will last about 3 months, a stock will last about 6 months.
Cargo Master
Joined: Mar 2003
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The oem coil is powered through a resistor wire.
The resistor wire is what powers the coil AFTER start up of engine.
The voltage to the coil is reduced while running.
OEM coils and some aftermarkets will fail prematurely if they are supplied full voltage on a constant basis.
SOME aftermarket coils require FULL voltage. You should look at literature regarding your coil and determine if you need full voltage or a resistor.
The resistor wire is what powers the coil AFTER start up of engine.
The voltage to the coil is reduced while running.
OEM coils and some aftermarkets will fail prematurely if they are supplied full voltage on a constant basis.
SOME aftermarket coils require FULL voltage. You should look at literature regarding your coil and determine if you need full voltage or a resistor.
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From: Broken Arrow
Replace your ground cable. I went thru 4 accel super stocks in about 2 years. tried everything moving the coil, changing coil and plug wires, etc.. someone suggested replacing the ground cable. replaced the ground cable and added a second one (one to the engine and one to the frame) that was two years ago and I haven't changed a coil since.
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Senior User
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that is an idea!
I will admit, the ground cable that runs from the engine to the frame / body, isn't that great. The ground cable from the engine to the battery was just replaced maybe a year or two ago, and is in fantastic shape. I will definitely look into that one!
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Senior User
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I completely forgot about the resistor wire... I will have to check the voltage at the coil to see if there is a resistor there or not. I don't remember. I know the actual wire itself doesn't look that great. Pretty poor shape. that may be causing some of the problems as well. Should I replace it with a heavier gauge wire? I think the factory wire is only something like 18 gauge.
Cargo Master
Joined: Mar 2003
Posts: 2,333
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The replacemnt wire would kinda depend on what your coil requires.
If a previous owner had hacked or bypassed the resistor wire, you may need a new one or a stand alone unit (which Accel does make and recommends for some of thier coils).
If I remember correctly, my 67 Bronco has about 7 volts at coil after startup.
If a previous owner had hacked or bypassed the resistor wire, you may need a new one or a stand alone unit (which Accel does make and recommends for some of thier coils).
If I remember correctly, my 67 Bronco has about 7 volts at coil after startup.
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Senior User
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I have honestly never checked the voltage at the coil after it is running... If the coil that I have been running requires 12 volts, and say I am only giving it 7VDC, I would agree it will fail earlier than normal. I will check that out tomorrow
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Cargo Master
Joined: Mar 2003
Posts: 2,333
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But if the coil is being overpowered, that definately would be an issue.
It doesn't need to be running. Just turn on the key. Check at start and at run positions.
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Senior User
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yah, I was thinking the same thing right after I typed it. I am possitive there is 12VDC with it not running, but like I said, I have never checked it in any other possition... Will check tomorrow, and let you know what I find.
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