I have a 79 f-150 with a 351m. just a couple days ago it was starting and running, all though not quite in time (small miss). i went to start it day before yesterday and it would only turn and act like it was going to fire, but never did. it had new plugs, wires, distributer cap, & rotor button. I put a new control module on it. this did not help either. afterwards I pulled all the plugs cleaned them off (they were covered in gas from flooding while trying to start) and checked the gap. i tried to start it again and it fired a couple times. Now heres where it gets fun. I loosened the distributer and had a friend try to start the truck while i tried to adjust the distributer enough to get it to fire. It came close to starting as i turned the distributer as far as i could counter clockwise. So i pulled the plug wires moved them all clockwise 1 position and retried starting the truck. It turned over and ran fine. Now it will not start again. any suggestions on what may be happening?

 

The first tihing I would do is put your number 1 cylinder at top dead center and move your distributor to the correct postion to fire the number 1 cylinder then. You can be a little advanced if your like. Then double check your plug wires for correct fireing order.

Since you have allready changed the wires and cap, you might want to check the coil to make sure everything is still hooked up right and working correctly.
You also might want to check your battery and alternator to make sure thay are up to snuff. The reason I say this is because my '79 would give me fits starting every once in awhile and the problem turned out to be that the alt. wasn't putting out enough voltage and the battery was slowly dying out on me. It had enough juice to turn the motor over, but wouldn't fire up. A quick way to tell if this is the problem, will be that you'll be able to start right up with a jump from another car or battery charger.

The reason I say to reset your distirbutor is because after a person makes so many adjustments with no results it is hard to figure out what to do next and you have to go back to the beginning.

If everything checks out an she still won't fire, pull a plug and set it on a grounded part of the truck with the wire hooked up and try turning it over while watching the plug. You do this to make sure the plugs are sparking.

Hopefully, if you go through all this you will find your problem. If eveything still checks out and it won't start I would guess the problem isn't in your ignition system.

 

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Providing that you haven't had the dizzy outta the hole for something, you shouldn't mysteriously have to re-stab the dizzy. Makes me wonder if the timimg chain is jumping teeth on the cam gear. If so, there should be a lot of slop in the gear set and chain. Take the dizzy cap off and turn the crank shaft by hand (with a tool of course) back and forth and see if the rotor moves in correspondence with the crank. If the crank seems to turn several degrees before the rotor button does, the gear set may need replacing. If the original timing gear set is in there, I would almost bet on that being the cause.