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Discussion Starter #1
Summary:

1979 coupe, 350.
Had a short problem that killed the starter, alternator, and battery in the summer.
After months of testing, I found an exposed wire (orange) tucked away behind the HVAC controls that was 12v hot with the key in acc or ign positions.
Not urgent: Figure out what that wire is for and decide if I want to fix it
Urgent: Car will not start, even with a 2nd new starter (1st new one was in the summer)

Testing on the starter so far:
Verified continuity from battery post on starter to positive terminal on battery
Verified continuity from IGN post on starter to the big positive wire junction that sits by the heater core box
Shorted BAT and IGN posts on starter as a test, gear comes out and engages flywheel but does not spin
 

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This is an end view of the starter solenoid on my 68 and if you short between the large battery post where the large cable is that goes to the battery positive post and the small solenoid stud labeled S with the purple wire in the picture, the starter should start cranking over the motor. For this test you do not have to have the key on so leave it in the off position.



If the starter does not make any noise, then check the ground cable and connections between the battery negative post and the engine block. Also then check to your positive cable connections.

If the starter just makes a noise but does not crank over the motor, then check the small bolt connection on the flat wire coming out of the main starter housing that threads into the bottom hole of the solenoid.

Wiring info for the starter solenoid circuit to crank the motor over:





Once we get things cranking over we can go further.

I'm taking it you have a test light or meter ?. If so what one or both ?.

The R post or what some refer to as the ignition post stud on some starter solenoids up to like the 1974 models will only show full battery voltage when the starter solenoid is cranking over the motor or will show a lower voltage when the starter motor is not cranking over the motor but the ignition key is in the run position. If the car has an HEI, after like 1975, then there is no resistance wire needed and then the R post may show full battery voltage when the key is in the run position. Some cars after 1975 might not even have this second ignition stud on the solenoid.

Jim
 

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I have HEI, with only two posts on the starter: Battery and S.
Before posting this, I actually verified the wiring from a diagram I found in another post here (my car is like the first picture you posted).
I followed the "S" wire from the starter all the way to the firewall behind the fuse block.
I also followed the brown wire to the big junction with a bunch of red wires going into it.
It's brown on the starter side, and red at the junction. Somewhere behind the block where I can't reach is the fusible link, I assume.

Last night, I did the test with shorting the S and Battery posts together.
The starter gear comes out and engages the flywheel, but does not spin.

Today, I lowered the starter to see if it would spin without interference from the flywheel.
It does not.

Then, I used jumper cables from the battery to the starter.
I put the negative on the block that mounts the starter to the car.

Then, I touched both the S and the Battery terminals on the starter with the positive side of the jumper cable.

The gear comes out and spins like normal. = WORKS

I have a test light and a meter.

I tested for resistance from ground to the S terminal, was reading .8, I don't know if that means anything.
A friend at work says not to use "continuity" for that test but a resistance reading instead.
 

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Problem with starter fixed:

If anyone wants to know the solution:
Check and inspect all connections
The rubber around the positive battery cable (at the battery) was melted from trying to start the car over and over with a short in the system.

Long story short: car wouldn't reliably start with the short, and I kept trying, replacing, and testing things.
While trying things (or maybe even before that) the rubber melted around the parts on my home-made side-post battery cable bolt solution.
 

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that's cool that you got the starting problem fixed. sometimes its the easy stuff to fix.
 

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that's cool that you got the starting problem fixed. sometimes its the easy stuff to fix.
LOL well after replacing a couple relays, LED's... at least it was the only MELTED thing I found. Probably on account of the 1ga Battery to body ground wire I put in awhile back.
 
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