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Discussion Starter · #1 ·
My 69 mustang is odd. There are times where I drive it and it runs normal. And there are times where I’ll drive it for over 30 minutes or so, park it at a store for a quick 4 minutes, come back only to crank my mustang but it won’t start. It has gas and I floor the gas pedal while I crank it but to no avail. The more I crank it or longer I done it the more it’ll crank slower and slower which I don’t like. Has this ever happened to anyone? The only solution that works for me is to wait for about an hour or so and eventually it’ll start, which is odd.
 

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When I do a warm start I crank the engine and if it doesn't fire after after a second or two I slowly press the gas pedal until it fires, has never failed to start.
The more I crank it or longer I done it the more it’ll crank slower and slower which I don’t like.
Wouldn't you expect it to crank slower as you drain the battery? If you don't like it get a better battery.
 

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Time to determine if the problem is fuel-related or ignition-related. When it won't start do you still have spark at the coil? If you remove the air cleaner lid and peer down the carburetor throat is it wet and stinking of gas?
 

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Discussion Starter · #6 · (Edited)
I remove the air lid from the carb and gas appears in it. So chances are it could be ignition related. However there should be spark cause eventually I’ll be able to start it after an hour or so of waiting to cooldown. I have a new battery and I always disconnect the negative whenever I’m not starting my car.
 

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Don't floor gas pedal on a warm or hot engine

Cold start 2 pumps, turn key
Warm engine 1 pump
Hot engine no pump

Agreed your coil can be on the edge of its life.

If car has been sitting for weeks
Crank it a few times in 3 second bursts to fill the bowls. Don't touch pedal.

Then pump twice and start.
 

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If gas boils out of the carb it floods the engine. Next time it happens, push the gas pedal to floor while cranking and see if it is going to start. If it is flooded, it should start with pedal to the floor. Then you can install a phonelic spacer under the carb to eliminate some of the heat.
 

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That’s probably it for sure. We’re talking about the shock coils fur the ignition right?
Yes, your "ignition coil". The round cylinder thing with the cable coming out of the top and going to the Distributor cap. Also, if you are running "Points", check the setting. What is the history of all of the ignition parts. When asked how long this has been occurring you state .."Forever". How long is "Forever"?
 

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Discussion Starter · #15 ·
Gotcha. So i was able to start it after hours of cooling down and managed to drive it, but it seems it’s the ignition coil that’s dying. Can anyone recommend a good replacement that’ll last forever?
 

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Resist the urge to start throwing parts at a problem you haven't isolated. If it doesn't start, check for spark. If it has spark it's probably suffering from "percolation". DO NOT pump the pedal. Just press it directly to the floor and hold it there. Do not let it back up until you are done trying to start the engine.

This assumes that your engine cranking speed, when hot, isn't any different than when it's cold. If the engine isn't starting because the cranking speed is too slow then you have other issues to address.
 

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Gotcha. So i was able to start it after hours of cooling down and managed to drive it, but it seems it’s the ignition coil that’s dying. Can anyone recommend a good replacement that’ll last forever?
Ain't nothing lasting forever. LOL. Check with NPD or Virginia Classics for a coil. Does your carb have a separator between the carb and the intake? As someone else mentioned, could be fuel percolation or Vapor lock. This occurs when the heat of the engine is transferred through the intake and into the carb .The heat can be so intense, the fuel is heated in the carb bowl(s) and percolates out of the air horn or other internal passages. Vapor Lock occurs when the fuel in the lines is vaporize, thus not liquid. This "hot air" finds it's way to the carb with no ability to be atomized. Allowing your engine to "cool down" will many times suffice for it to start. Your symptoms are consistent with these two possibilities.
Does your engine smell unreasonably hot? The OEM gauges are notorious for not being accurate. It has been advised here, numerous times, to add a non-heat conductive separator between the carb and intake to reduce any excessive heat from reaching the carb.
 

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Discussion Starter · #18 ·
Ain't nothing lasting forever. LOL. Check with NPD or Virginia Classics for a coil. Does your carb have a separator between the carb and the intake? As someone else mentioned, could be fuel percolation or Vapor lock. This occurs when the heat of the engine is transferred through the intake and into the carb .The heat can be so intense, the fuel is heated in the carb bowl(s) and percolates out of the air horn or other internal passages. Vapor Lock occurs when the fuel in the lines is vaporize, thus not liquid. This "hot air" finds it's way to the carb with no ability to be atomized. Allowing your engine to "cool down" will many times suffice for it to start. Your symptoms are consistent with these two possibilities.
Does your engine smell unreasonably hot? The OEM gauges are notorious for not being accurate. It has been advised here, numerous times, to add a non-heat conductive separator between the carb and intake to reduce any excessive heat from reaching the carb.
That was extremely helpful. So I am getting the Trans-Dapt Performance Carburetor Spacers for sure. As for ignition coils, what do you all recommend? It seems the MSD are popular but I can’t figure which one to choose.
 

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That was extremely helpful. So I am getting the Trans-Dapt Performance Carburetor Spacers for sure. As for ignition coils, what do you all recommend? It seems the MSD are popular but I can’t figure which one to choose.
NPD is a highly rated vendor of parts for our Mustangs. Check these as they are more in keeping with our vintage vehicles. Hopefully, you purchased a "non-metal" version of the spacer.

 

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Discussion Starter · #20 ·
NPD is a highly rated vendor of parts for our Mustangs. Check these as they are more in keeping with our vintage vehicles. Hopefully, you purchased a "non-metal" version of the spacer.

What do you think of these two I found so far? Better or worse?



Unless any of you guys have recommendations I’d be happy to hear.
 
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