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Coil gets HOT and engine cuts out. 1984 F250


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Ohhhhhh, I hear ya.

I did replace the ICM , but now you have me thinking.

I remember you saying that, but you're the one that figured out that your ignition switch is bypassing the resistor wire.

So now we know that all these components have been putting up with a lot more current than they are designed for.

First let's fix the switch situation.

Gary pointed out that the wipers inside must have some overlap.

So either the detent needs to be stronger/deeper or the wipers need to be shorter in the overlap.

Or, a little of both

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I remember you saying that, but you're the one that figured out that your ignition switch is bypassing the resistor wire.

So now we know that all these components have been putting up with a lot more current than they are designed for.

First let's fix the switch situation.

Gary pointed out that the wipers inside must have some overlap.

So either the detent needs to be stronger/deeper or the wipers need to be shorter in the overlap.

Or, a little of both

I'm going over to check if I have a gearshift for Shaun.

Maybe I have a spare ignition switch too.

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I'm going over to check if I have a gearshift for Shaun.

Maybe I have a spare ignition switch too.

I grabbed yet another ign sw from the boneyard this week.

How about if I throw the ballast resistor in, it cant possibly hurt right?

The crazy thing is, this is pretty basic stuff. If I cant figure this out I deserve to stay home.

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I grabbed yet another ign sw from the boneyard this week.

How about if I throw the ballast resistor in, it cant possibly hurt right?

The crazy thing is, this is pretty basic stuff. If I cant figure this out I deserve to stay home.

I would say "it can't hurt"... but that's not fixing it.

That's like saying "my leg has a compound fracture. What if I just take some painkillers?"

Don't be frustrated.

It's exactly when something goes wrong with a 'foolproof' system that's functional for millions of others, that you need to be clearheaded.

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This is odd,

When idling the voltage to the coil is 10.5, but higher revs gives me higher voltage, past 12.

Maybe voltage regulator?

That's easy to explain. When idling your alternator is basically not charging the battery so your voltage will probably be about 12.6. But when you rev the engine the alternator does charge and the voltage probably goes up to about 14.4.

Doing the math, 10.5 divided by 12.6 gives .8333. And 14.4 times .8333 = 12.0.

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That's easy to explain. When idling your alternator is basically not charging the battery so your voltage will probably be about 12.6. But when you rev the engine the alternator does charge and the voltage probably goes up to about 14.4.

Doing the math, 10.5 divided by 12.6 gives .8333. And 14.4 times .8333 = 12.0.

A 1.1 ohm resistor would be dissipating 11-13A at those voltages!

No wonder it was getting hot when (Matt?) asked about the hot dash harness.

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That's easy to explain. When idling your alternator is basically not charging the battery so your voltage will probably be about 12.6. But when you rev the engine the alternator does charge and the voltage probably goes up to about 14.4.

Doing the math, 10.5 divided by 12.6 gives .8333. And 14.4 times .8333 = 12.0.

So do we do the ballast resistor, at least for now?

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