Fires up, but stops after ignition is released.

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7

74 dart sport

Kameron
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We have yet another problem (they are endless lol). Yesterday, we were able to get the 318 fired up nicely. When we went to start it today, it would fire up when I engaged the starter, but would cut out as soon as I released it. I can smell a lot of unburnt gas.

We know that:
1) The problem started overnight, with no human interaction.
2) The engine is getting gas.
3) The coil (Pertronix III Coil and Distributor) is working.

Any ideas as to why it is cutting out?
 
There are two sources of ignition, "at different times."

There is IGN1, traditionally dark blue, which is hot ONLY with the key in "run." This supplies stuff like some of the smog stuff under the hood, the regulator power and alternator field, and the run voltage for ignition. It goes to the ballast resistor, and to the ECU

IMPORTANT: The above voltage is NOT hot in "start" only "run"

NEXT....

is the coil resistor bypass circuit, IGN2. This is normally brown, and only goes one place.........from a contact on the ignition switch, through the bulkhead connector, and to the coil + side of the ballast resistor. It is ONLY hot during "start."

Since the thing starts and dies, either you screwed up and left a wire loose when you spliced them together, or the bulkhead connector has a loose connection in the "run" wire, or there's a problem in the ignition switch connector and switch.

Also some of the later cars have a disconnect connector between the firewall harness and the engine. These are designed so the factory can quickly install the engine and have caused trouble.

DO YOU guys have a shop manual and or wiring diagram?

You can download them free at MyMopar. In addition, there's other good info there. Some of those manuals "over there" came from the hard work of the guys here at FABO

http://www.mymopar.com/index.php?pid=31
 
Just start it and hold the switch from coming back all the way if it stays running. You need an ignition switch...
 
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