on my 1978 bronco with a 460, mallory comp 9000 distributer, mallory ignition coil, and wires, is not running. I replaced the ignition module inside the distributor and hooked up an accel coil and still no go. I am getting very little spark when i test them, little to no spark at all unless the tester points are very close. It still backfires and ive even shot a flame out the tailpipe. For three weeks we have been cranking it and the batteries are still good and its still cranking strong. I just cant get it to start. I think its got to be the ignition if im not getting the spark cause i dont think its internal. Ive checked the carb as well and thats fine. 3 weeks ago we started it, reved it to get it to idle and then it stopped and would not start the rest of the day. Went out the next day and it still didnt start so i sprayed choke cleaner in it, then opened the top plates on the carb to allow air to get in and it started for a second then stopped and wouldnt start again. i looked under the hook and found that the alternator bolt broke so it fell and after i replaced that it still wouldnt start. Any help would be great, right now i am without a car so if there are any ideas it would be greatly appreciated. thanks
Joseph

 

First of all you need to eliminate fuel being the cause. If you open the choke plates and look down the primary bores while working the throttle back and forth you should notice fuel squirting from both barrels. If you have fuel squirting, you know you have fuel delivery to the carb. Next spray some carb cleaner or spash a little gasoline down the carb, if it starts and runs for a few seconds (as you described earlier) your carb may be plugged and need rebuilding. You can also accomplish this by pumping the gas pedal while cranking if you have fuel in the float bowl.

If your fuel system is in good shape, you can test the ignition system. First thing to do is to test all powers and grounds dynamicly. This means using a DVOM and doing these tests while cranking the engine to be sure that there are no excessive voltage drops, causing your ignition system to not work properly.

If all powers and grounds are good, ensure that you coil is getting triggered. You can do this by placing a test light on the neg. side of the coil. While cranking the light should flash on and off indicating a proper signal to the coil. If the light just goes dim and bright due to the amperage spikes during cranking you have no coil triger. Let me know how it goes up to this point and if you require more advice I will take this testing further. Good luck!!

Nick from the frozen north
1974 F-250 4X4
soon to be 429
dana 60 front and rear