Coil Failure(s)

[Dragon Slayer]

You need to reread what I said. I know how it works. Your assuming for him. He may be mistaken in what he wrote, but as written in the method he used he does state he has 12.5V on + of coil in run even though he states output of ballast is 9.1. So both can't be correct unless he posted wrong, or he has a wiring issue with input of ballast on the + of coil.

If he truly has 12.5 on the + of coil while running, that certainly could explain why coils are failing on him. Which is what the original problem claims.

He could also put an amp meter in series with coil + from ballast and read amps.

 

[Sinitro]

Keep in mind..
The purpose of the ballast resistor is to limit current to the coil, and its resistance will vary as it heats up.

Just my $0.02...

 

[Geoff 2]

DS,
I don't need to re-read what you said, I understood. The confusion is how the OP has stated things, a bit confusing but I understood what he meant....
'Bal res 10.5v/7.5 at idle'. He means the BR has 10.5v on the input or ign sw side & 7.5v on the output or coil side; this is born out because further down he quotes the same 7.5v at the coil.
The 12.5v/9.1v is also the voltage at each end of the BR, but at 2000 rpm.

 

[Geoff 2]

I see where he says 12.5v @ 2000 rpm after coil +, obviously cannot be correct given the other readings; looks to me he made a mistake & meant to repeat what he said earlier, 12.5 on the ign sw side of the BR, not 12.5v the coil side.

 

[Dragon Slayer]

Then what does this mean since he posted it?

"Coil + Post @ start. 7.5V
@ run. 12.5 V @ 2000 rpm."

Why answer for him? 2 ears one mouth, lets listen to him explain his post. Then we will know what he measured vice what you assume he meant.

 

[Dragon Slayer]

Then what does this mean since he posted it?

"Coil + Post @ start. 7.5V
@ run. 12.5 V @ 2000 rpm."

Why answer for him? 2 ears one mouth, lets listen to him explain his post. Then we will know what he measured vice what you assume he meant.

Ok so now you see what I was saying! So you did need to reread what I said

 

[dadsbee]

Wouldn't it be great Dave if it was two wimmin fighting over you??

 

[Dave6T4]

I re-read my post from last night, and it did not make sense to me either. I must have transposed a couple of things. I fired the car up today, and rechecked voltage at coil positive post:
7.7 V at idle
9.1 V at 2000 rpm.
Sorry for the confusion that seems to have caused some bad feelings. Thanks again for assistance.

 

[Dragon Slayer]

That does look normal.