300 Ford TBI'd. Developed an issue on start.....when it starts. My coil bracket broke and the coil fell on top of the distributor cap while driving one day .Truck wouldn't start due to lost ground. Fixed the coil bracket but now truck does not want to start easily. I can crank it and it will make what sounds like 4 revolutions then its almost like the motor locks up. It has like a pause then will continue to crank but will not start unless I hold the throttle open. I cannot small any gas....injectors are not leaking...checked. When it does finally start...sometimes takes a while, there is no cloud of black smoke. Once it starts it runs and idles fine. I swapped out my chip for another that I had burned and it does the same thing. The cranking issue is what gets me. Same everytime....4 cranks then thunk, resume cranking. Cap is not cracked, all plugs are connected, distributor is not loose. No wires appear to be cut or damaged. I have included a pic so you can see where the coil was/is. Any ideas?

 

Weak battery? Poor battery connections/undersized cables/corroded wire harness?

Ignition timing overly-advanced?

 

Battery is fine. Timing is 10* BTDC. I actually thought the timing could be the culprit till I verified it was what it has always been. I have some spare ECMs laying around. I am going to swap it out next. I have a Jeep I TBI'd that ran great and then suddenly it wasn't. Nothing horribly bad....just started to run rich, idle not that good. Swapped out the ECM and it all cleared up. Put the old ECM back in and the issues returned. Its just the "thunk" after 4 cranks that gets me.

 

HOW was it tested? Were the cables checked for voltage drop? What is the starter amperage draw?