Hi, I do not have wiring diagrams for the F-750, but I'm assuming the ignition systems are similar for all trhe F series trucks. Are you getting battery voltage to the coil when the key is in run and start? If not, first verify the fuse is good. If there is a noise capacitor on the positive coil wire, remove it temporarily while troubleshooting. If that cap is causing low voltage to the coil, replace it. If you still cannot get power to the coil, the problem may be the ignition switch. If you have power to the positive coil terminal, pull the coil wire out of the distributor and lay it on the engine where it has about a quarter inch gap to engine ground. Turn the key on and momentarily jump a ground wire to the negative coil terminal to see if it will release a spark. If the coil will release a spark this way, the problem is back in the distributor. Was everything in there replaced? Please let me know if you have questions.
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