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1966 Mustang - Engine Won't Start

2683 Views 8 Replies 4 Participants Last post by  Dark

I own a 66 Mustang, I6 auto C-4.

I recently replaced the alternator, ignition switch, starter, and starter solenoid. Everytime I try and start the car, the starter motor stays stuck to the point where it sounds like the car is at full throttle without even depressing the accelerator.

I disconnected the throttle linkage and even bypassed the solenoid with a screwdriver, but the starter still stays stuck(the speed at which it's turning sounds like the engine at full throttle). I had a mechanic show me this trick and he was able to get it started a while back, however recently the car either cranks aimlessly or the starter catches, there's no in between.

Took the starter to get checked and it passed. I'm completely out of ideas and paranoid about turning the car on given the fact how many times the damn starter has stayed stuck.

Any help would be appreciated. At the end of my wits here. The car has been sitting for six months
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Your story is confusing. Does the starter engage and turn the engine over? Will it release on its own? Does the engine actually start and race to high RPM or is it just the starter spinning freely?

You may have the wrong starter for your car. Could be the nose cone is wrong, or the number of teeth on the gear. Are you sure you are giving the parts store the correct info for the engine and trans that is actually in the car. Has either the engine, bell housing, or trans been changed?
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Okay, here's my 2 cts. First off, once you release the ignition key from the START position, the power to the S terminal on the solonoid should be gone, which in turn releases the solonoid, so I would try to start the car with it in park, hood open, and if it stays cranking, then pull the wire off the S terminal on the solonoid, and it should stop cranking (if it does, then you either have the wires switched, or have something providing power to that wire during the run position, so I would double check your wires on the ignition switch to make sure you do not have one on the RUN terminal that should be on the START terminal), if it still continues to crank, then take something plastic like the handle on a screwdriver and tap the solonoid and see if it releases, if it releases, then it is the solonoid sticking, buy a better quality one. In addition, the I terminal on the solonoid is a direct connection to the ignition coil + terminal, this is to supply battery voltage to the coil during cranking (START position on the ignition switch), when the ignition switch is in the RUN position, then the coil gets power through a pink resistor wire which drops the voltage to around 6 volts to the coil with the points closed, this prolongs the life of the points and keeps from overheating the coil. A good practice, when replacing electrical parts, is to make sure it is working correctly, before you replace the next one, because if you make a mistake, it will be harder to find, if you replaced several things at a time. Post your results. Good Luck.
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Thanks for the replies.

In regards to the first responder, yes the engine was changed. It's still the Ford I6 motor. The starter is the correct size and part number etc. In regards to the noise, the starter sticks, sub-sequentially speeding up the engine itself. In other words, they'll both be running at the same time, with the starter spinning and stuck at full speed and engine revving high.

It's not the solenoid because once the key is removed, the starter stops versus other times when the solenoid was sticking, the engine would keep running even with the key removed.

I'm certain the wiring to the solenoid is correct.

As I said, I had a mechanic come over a couple weeks ago with the same problem. He jumped the solenoid with a screwdriver and it worked fine. I was able to turn it on a couple of times after that, but now it won't budge
If the car runs fine from a solenoid jump then it sounds like it might be a switch issue. Does your key return to the run position after you crank the car, if its hanging up in the start position then its going to leave the starter running. As stated before I would make sure the ignition switch is wired properly, then I would make sure the switch itself is working properly, I've replaced two in my car and every parts car I have has broken switches. They don't hold up well. you can always bypass the switch and jump the wires and see if it cranks normally then, if so the switch is your culpret
No, the key doesn't get stuck in the start position. Even when we bypass the solenoid with the key simply on the
"ON" position, the starter will still get stuck to the engine.
I think you missed some of the points in my earlier post, please reread it and try the things I said, they will determine where your fault is, as you have to determine, whether it is starter drive sticking, solonoid sticking, ignition switch problem, wiring problem, at present you have too many possibilities, and have to narrow it down. My 2 cts. From an old mechanic. Good Luck.
Thanks for all your input.

I changed the solenoid and igntion switch. Had the mechanic come over and put some starter fluid and it started right up.

Unfortunately, now the idle RPM is way too high. He told me that the reason my car was idling too fast was because one of the carburetor mounting gaskets might be on backwards, making it hard for some part of the carburetor to close. (can't remember exactly what part)

Is this true? I feel it might be the distributor vacuum advance since when I got the engine, the previous owner had ziptied the hose shut. Could fast idle also be due to bad timing or some adjustment to the carb other than the idle screw?

Thanks for your help
Yes, in theory. Carbs are funny, one clogged port in there could cause it to not function as intended, so if the gasket were covering a port of some kind then it would cause problems. thing is, you don't know what the guy before you fiddled with. Your settings could be off, your carb could be dirty, you might have gaskets on in the wrong place. the simple things are the easiest to start with but If you have never fooled with carb adjustments before you should read up on it. It could be that the idle set screw is just to fast, but carbs are not a one screw fixes all. Find out what carb you have and google adjustments on it. A good deep cleaning of your carb might be necessary
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