NO START WITH KEY

[weezer]

I've searched the forums but haven't found exactly what I was looking for so I'm going to start a thread specific to my problem. Thanks in advance for any and all help. I have a 1970 Dodge D100 that I got back in May. Worked thru some small stuff to get it running but now I'm hung up. New starter, new alternator, new voltage regulator, new ignition switch, new plugs, wires, cap, rotor, points, new radiator,fresh gas in tank. With a fresh charge on the battery (12.6 volts) it will start right up by jumping the starter with a screwdriver or the relay on the fender with a screwdriver. But if I sit in the seat and try to start it with the key, it will RRRRUH, RRRUH, RRRRrrrrrrrr and quit. Or not even turn over at all sometimes. No click, no ruh-ruh, no nothing. Is there a bad wire/connection between the switch and the relay/starter? How do I find which it is and where do I start to look? I can provide more details for specific questions anyone might have. Thanks again.

[ufo]

I would check the connections at the bulk head.
That's a very common area for electrical problems.

[deadendcustoms]

Also, one thing you might try would be running a jumper wire from the + battery terminal to the + coil terminal, temporary of course. Once that's connected try to start the truck. I agree you might have a bad bulkhead connector, but it might also be in the switch. The start position partially failed in my 67 W200 and now it won't power the coil while cranking. On occasion, it would start just as I let off the key since it's still powering the coil in the run position. Right now I've got a momentary push button inside the cab so I can crank the engine over a few times to get it up to speed, then push the button giving it spark It makes a big difference when trying to start a 440 with the old direct drive starter, plus I can run a few more degrees of initial timing and not worry about kicking back on the starter.

[weezer]

I would check the connections at the bulk head.
That's a very common area for electrical problems.

OK. How do I check them? Do the connectors just pull straight out of the bulk head? Clean'em and plug'em back in? Thanks.

[weezer]

Also, one thing you might try would be running a jumper wire from the + battery terminal to the + coil terminal, temporary of course. Once that's connected try to start the truck. I agree you might have a bad bulkhead connector, but it might also be in the switch. The start position partially failed in my 67 W200 and now it won't power the coil while cranking.

Thanks. I will try this, too. What gauge wire should I use for the jumper?

[deadendcustoms]

Most any size will work for the jumper wire, I've got a length of wire that's probably 14 or maybe even 16 gauge with alligator clips on the ends that I keep in my tool box for helping to track down various electrical problems, or even to make temp repairs while on the road and I've used it a few times for jumping power to the coil. If starting from scratch I would probably use 12 or 14 gauge just so it's more versatile. Alligator clips aren't necessary, you can just tuck the wire under the nut on the coil and stuff it down in the battery cable in a pinch too.

[weezer]

...I've got a length of wire that's probably 14 or maybe even 16 gauge with alligator clips on the end...

I have one of those, too. I'll try it out this weekend and get back to you. Thanks!

[Neglecto702]

My 1970 dodge 100 wouldnt start with the key, but would with a jumper button from starter to battery. After switching the battery, the relay, the starterswitch, all the wiring lengths under the dash. I finally found out what it was, the Neutral safety switch. Now the truck runs perfectly and starts everytime. Hope it helps.

[40YearOldFury]

I just had that issue after putting my truck back together intermittently and just had to clean up and tighten the connections on the back of the ignition switch