86 Ford Thunderbird won't start.

ls1mike

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Ok 86 3.8. No spark out of the coil. 9.8 volts to the coil when cranking. Here is the kicker When you turn the key from run to start the spark tester will light then once the car starts turning over (key in the start position) no light in the tester. When you go from start to run, quick flash of the spark tester then nothing. Any ideas?
 

ls1mike

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Where is that? I am not to familiar with this car. It is a buddies kids. Is it the little grey box under the starter selnoid?
 

ls1mike

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I meant to also say the coil has been replaced and if the TFI is the iginition module on the distributor that has been done too.
 
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Long time sense thinking about the old Ford systems. I think they supplied full voltage with the key turned ON. (That’s why it sparks while holding the key.) Then when you let go of the START position with the key, a secondary circuit with a ballast resistor took over to supply less voltage/current to the points/ignition system. Find the ballast resistor/fuse/fusible link that is now open/bad.
 
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Starter relay. That’s where it all starts. One of the small wires supplies +12vDC to pull the relay. The other smaller wire at the top supplies full power to the ignition while the key/starter is on. When the key is let off, a secondary circuit supplies power to the ignition with a ballast resistor in the circuit. Now, where is that secondary circuit?
 
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Used to be with points when you turned the key off if the points were fused, you'd get one spark because then the coil would discharge because it had been interrupted. I +5 the idea the TFI went south. Can you check the injectors, for grins?
 

ls1mike

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I'd check ignition switch and crank position sensor. I've had 3 of these engines. Some of them had faulty ignition switches that didn't make proper contact. One in particular, had to be manually turned back just a bit for all the electronics to work.
 

OVERKILL

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Originally Posted By: SS1970chrysler
I'd check ignition switch and crank position sensor. I've had 3 of these engines. Some of them had faulty ignition switches that didn't make proper contact. One in particular, had to be manually turned back just a bit for all the electronics to work.
Yup, the one on my Mustang was a little goofy that way, if you wiggled the switch, you could make the engine die. Mind you, it had over 330,000Km on it when that started happening, LOL
 
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