burning up condensor

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pops53
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burning up condensor

Post by pops53 »

Hello....

I have a 1966 F100 240-6 that keeps burning out the distributor condenser. The truck just dies, (very weak spark), I replace the condenser it runs for a few miles then quits. Any ideas?
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Re: burning up condensor

Post by fordman »

Is it all stock.
tac
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Re: burning up condensor

Post by tac »

Probably no resistor wire for coil.
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Re: burning up condensor

Post by pops53 »

Yes it is all stock. Could the ballast resistor be bad? I do have spark but it is very weak.
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Nitekruizer
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Re: burning up condensor

Post by Nitekruizer »

Unless the wiring of your truck has been altered, the pink "resistor" wire is the ballast resistor in these trucks.

The first thing that I would do, assuming that you've already checked for broken wires and bad or loose connections, would be to check for voltage at the Positive (+) terminal of the coil with the ignition switch in the "run" or "on" position. The engine doesn't need to be running for this however. You should get a reading of 6 to 8 Volts if the resistor wire is good.

If you are getting 12 Volts at the Positive (+) side of the coil, the resistor wire is probably not there, has been removed or bypassed. Have a look under the dash for a thick, soft, pink wire.

If you are getting 6 to 8 Volts at the coil, like you should be, then I would check the points by connecting the Positive (+) Test Lead of the Voltmeter/Multitester to the Negative (-) terminal of the ignition coil. Ground the Negative (-) Test Lead to the engine. With the ignition switch in the run position and the points fully closed, do not start the engine, you should get a reading of somewhere around 0.2 Volts. A lower reading is best. If you get a reading of more than 0.4 Volts, install new points.

I hope this helps. :)
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Re: burning up condensor

Post by pops53 »

Thanks much! I have a resistor mounted n the coil bracket hooked to h coil. I this the ballast resistor?
Is it located under the dash? My wiring diagram shows nothing. :help:
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Nitekruizer
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Re: burning up condensor

Post by Nitekruizer »

I just noticed that your truck is a 1966 and not a '67-'72.

Being a '66, I can't tell you for sure if that ballast resistor is supposed to be there or if your truck uses a "Resistor Wire" instead. You may still be able to tell using a Voltmeter/Multitester however. You could check the voltage at the Positive (+) side of the coil which still should be 6 to 8 Volts. Then check the Voltage just before the ballast resistor. If the voltage is around 12 Volts right before the ballast resistor, then your truck doesn't have a "Resistor Wire" and you need to keep using a ballast resistor. If the voltage is a steady 6 to 8 Volts before the ballast resistor, then your truck has a Resistor Wire and you shouldn't need the separate ballast resistor at the coil. Ideally, you want 6 to 8 volts at the coil. Too much resistance before the coil will drop the voltage too much and likely result in a weak spark or maybe even no spark.

The only exception to this would be if your coil has a built-in resistor. Some ignition coils do, but I'm not sure if Ford ever used such a coil. It may be a good idea to check the primary resistance of the ignition coil anyway.
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radioactivelarry
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Re: burning up condensor

Post by radioactivelarry »

65 and 66 have a ballast resistor. I too am having the problem of burning out condensers on my FE 390. First it starts at higher speeds like freeway speed and it starts jerking and the ignition seems to shut off momentarily and if you slow down it comes back to life. Soon it degrades to barely running at all with the engine shutting down and starting back up and jerking wildly. Install a new condenser and we're back on the road. I thought it was the cheap Chinese ones from NAPA but the last one I installed was a USA made NOS and now, tonight after a jaunt to the grocery store it is showing signs of needing another condenser very, very soon.

One thing I noticed was when I replaced the last condenser I also installed the new black wire that goes from the connection where the points and condenser connect and goes to the minus - side of the coil. When I was hooking up that wire the ignition was OFF and I noticed a little spark when I touched the minus connection with the wire. It's the black wire. I'm not sure if it should spark or not. The points were closed but I don't think there should be any voltage there or not and the coil is a new Accel 42,000 volt one. I also have a ballast resistor. I was thinking there was still a charge in the coil or the condenser or both that made the spark however I'm not sure. I haven't measured the resistance of the ballast resistor but I will tomorrow.

Here is the 64 thousand dollar question: Should there be any voltage there to cause a spark (a small spark) or is there something else going on and that's causing the condensers to blowing up. I don't think it is the fault of the condensers as something else must cause it. The instructions for the coil state it can be used with or without a ballast resistor. So far this is condenser number 3 and I will have to replace that one with number 4 tomorrow. Condensers are inexpensive but you can't take them back either. maybe I'll have to buy a 6 pack of condensers. :lol:
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Re: burning up condensor

Post by tac »

Should not have any voltage on coil when ignition switch is off. You can get a tiny spark from a charged condenser, but only one until its charged again. Check the voltage on the + side of the coil and points closed. Switch off should be "0", Switch in "run" should go through ballast resistor and read around 8 volts, in "Start" should route full 12V to + side of coil.
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