why is it dying?
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New User
Joined: Nov 2008
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why is it dying?
I have a 1977 ford f-350 with the 400-2bbl. It dies for no reason --sometimes while going down the road and sometimes while just setting still idling. I have put a test light on the power side of the coil and when it dies the light is still lit, so I still have power to the coil. It will re-start perfectly if you turn off the key and re-start it. It will not start if you hold the key in the start position--only after you release the key to the run position. Is it the pick up coil or the module? How do you test a pick up coil? I have replaced the ingintion switch. Everything is stock--with 32,000 original miles. When it dies it drops like you cut the key off and never makes an attempt to restart with the exception for the occassional muffler splitting backfire and it does it only once but thats all it takes to split a factory muffler. ANY help is appreicated. Thanks in advance.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
This is a classic example of the ignition module failing. When they are on their way out, they cut out when they get hot. When they shut off, they cool down enough to work again. You can have the module tested on a machine at most parts stores, but because the problem only shows up when the module is hot, the results are usually inconclusive.
It could also be the pickup module. The only test that I know of is a resistance test, but this is a Hall sensor and the resistance won't tell you much. It's just a go\no-go check. If you disconnect the pickup module and check the resistance between the purple and orange wire, you should see between 400 and 800 ohms. You should see open-circuit for the orange wire to ground and purple wire to ground as well. Lastly, check that the black wire is true ground (check the resistance between the black wire and the engine block, and you should see zero ohms). This is the ignition system's ground. The ignition module does not ground through the fenderwell, which is a common misconception.
It could also be the pickup module. The only test that I know of is a resistance test, but this is a Hall sensor and the resistance won't tell you much. It's just a go\no-go check. If you disconnect the pickup module and check the resistance between the purple and orange wire, you should see between 400 and 800 ohms. You should see open-circuit for the orange wire to ground and purple wire to ground as well. Lastly, check that the black wire is true ground (check the resistance between the black wire and the engine block, and you should see zero ohms). This is the ignition system's ground. The ignition module does not ground through the fenderwell, which is a common misconception.
Senior User
Joined: Mar 2008
Posts: 126
Likes: 0
From: FOLSOM CA
I had the same thang happen to my 71 High Boy with late model 460 electronic fuel injection, it was the pick up module in the distributor,one of wires going thew the housing had a small split in the insallation and would cause a voltage drop.A ten dollar part causing a hunderd dollar headache . Good luck
