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Irregular Starting Problem, 66 Mustang

We have a '66 Mustang that recently has gotten into SOMETIMES not starting. Sometimes, this takes the form of no sound when turning the key. Once, it took the form of turning over and a grinding sound coming from somewhere under the hood, and the starter wires getting hot and then the starter (or maybe the attached amplifier wire?) smoking.



The “work around” seems to be to roll the car a little and then it … so far … always starts fine. The battery seems good. We’ve changed out the starter (twice), but the problem continues.



Recent other work coming just before the problem started includes manifold work and replacing the rear light kits.



The work-around is fine so far, but we’d like to really fix the problem. Any good ideas?



Thanks!

Man the car is as simple as a box of rocks. A little review of your automotive basic’s should get you going. Are you willing to do some reading and review?

Ha, sure.

When you remove the starter, examine the large ring gear the the starter gear drives. It may have broken, or worn, teeth.
The starter may need shims to get the starter teeth to mesh correctly with the big ring gear. If the starter isn’t shimmed correctly, it can bind, or drag, when it tries to turn the engine. The battery-to-starter wire may have overheated, from a lot of current passing through it when the starter was in a bind. Rolling the car may ease the bind, temporarily.
Next suspect, the starter relay.

Thanks, Hellokit. I think the fellow who towed us last time (before we understood we could roll the car a bit and start it) was trying to tell me to check the starter gear teeth, but I didn’t follow him … your suggestion makes it clear. We’ll check the teeth and the shims. The sound made the one time the engine tried to turn over sounded like it could have come from the binding/dragging you described. We’ll check these things and report.

I may be asking the obvious. Have you changed the starter relay (also called the starter solenoid)? It really is not a solenoid as it only connects the battery cable to the starter cable. It will be over on the left side of the engine compartment. Follow the battery cable and starter cable to the relay.

Hope that is what it is.

Ford starters, 1966 vintage, are never shimmed…Remove and clean ALL the battery cable connections, including the ground cable(s)…"(or maybe the attached amplifier wire?)" no such thing…

I just let that kind of shimming advice go by. I knew FORD starters aren’t shimmed but I was waiting for the OP to write back “there are no shims”

When I made a mistake about what type of flasher relay a Cavalier used I was pretty soundly trounced told “if I want to give advice I better know what I was talking about” but I didn’t need to respond in kind.