Only runs when ignition turned to Start

[farmtruckman]

Figured switch was bad after I tested it. New one is good but truck won't run unless you hold the switch to "start" position. Wiring in truck a mess but can't find anything disconnected. Any suggestions?

Thanks,

FTM

[1970FordTK]

Re: Ignition Switch Diagram Needed
by 1970FordTK on Tue Jul 28, 2009 10:05 am

I had the same thing happen to me, my problem turned out to be a bad starter solenoid. Its easy to check for this, there are two slip on wires connected to the solenoid. The one closest to the fire wall is the one you want to remove (brown wire), once you have disconnected it see if it will start. If it does you need a new solenoid. Just my on this. If what I am talking about is about as clear as mud, please ask for a better explination and I'll do my best to make it clearer.

[70shortwide]

have you had the solinoid unhooked lately? maybe the wires are crossed..

[farmtruckman]

Thanks for tip. Tried disconnecting wire with no luck. Will swap out solonoid with another one I have just in case. Only thing done since it ran last was swap out plugs, check plug wires, and check timing (while it was running). Still looking for something else I might have disconnected but can't find anything. Any other suggestions welcomed.

FTM

[fordman]

didnt you just replace that switch or was that someone else that had that problem?

[m-mman]

The coil gets power from TWO places. The solenoid and the key.
When the solenoid is activited (key turned to crank) The small terminal on the solenoid gets 12V and sends it to the coil (what seems to be happening to you)

Release the key (run position) and power comes from the key through the ballast resistor to the coil. (6V -8V to the coil so as to not burn up the points)

Possible Problems -
Bad switch I had the plastic part of a switch PARTIALLY fall off once. (when pushed back on it ran when it fell away it stopped)
Burned out resistor
Broken wire from key to coil.

Not much else that it could be...

[farmtruckman]

narrowing down, but where is ballast resistor located. This has the Duraspark system from a 1980 Bronco installed. Is it mounted against radiator core support? I am in a hotel on a biz trip so I am working from memory here.

Thanks,

FTM

[fordman]

without a duraspark system the igniton wire that is pink pretty close to the ignition switch plug will be the resistor wire. it goes into the ignition plug. to putin a duraspark and run a ballast resistor. you get rid of the pink wire and wire around it. the ballast resistor can be anywhere in between where the pink wirer was replaced at and the coil. it is the choice of the installer where to place that new resistor at. alot of guys have just bolted them right to the firewall.