hi there all. 78 f250 400 cid. when i turn the key in the ignition switch to the start it turns over and starts,the key then returns to the run selection and everything is fone. but alot of the times when i turn the key to start selection it turns over fine but does not fire until the key is turned back to the run position. would this be a problem in the ignition switch or could it be a problem in the starter relay or somehwhere else?when it did it today the truck runs but kept konking out every so often just like if i turned the key off while i was driving,but i still have electrical power to the radio,lights etc. it fires right back up again though but its a real pain in the #$% .

i would appreciate any help. thanx

 

Sounds like a bad connection somewhere. Start the truck and start moving wires.

 

It could be the switch. The ignition gets 12v in the start position and around 8v in the run position. Do you have a lot of miles on it? Try wiggling the key around when it quits.

 

i had a problem of it dying when i was driving or just idleing. i swapped many parts but it never got fixed until i change the ignition switch.

 

hi again. after going throught the wiring i have figured out.... NOTHING!!lol
what i have figured out is the coil+ is getting 12 v in run mode so im guessing i have no resistor. the wire that goes to the coil goes under the dash but i havent traced it under the dash yet. the wire at "I" on the start relay is also getting 12v.

when i was looking for faulty connections and such, the connector at the 2 wires coming from the cab to the ign module(red and white) was junk with exposed wires. so i chopped it out and made a new connector for these 2 wires. but then it seems i lost my "run" circuit. the start circuit worked fine but as soon as the key was turned back to run,dead. the white wire is Run and the red is start? is that right? i have 12 v at the white wire in run mode but no running is happening. just alot of cursing(poor kids) BUT for some reason just for the heck of it i put the red from the ign switch to the white from the module and white from the ign $ to red from the module. then it fired right up and is running. i havent driven it anywhere it cause im afraid it will die on me. i am wondering what the heck is going on? anybody with any ideas why this is working. im sure there is a logical reason but my circuit knowledge is a but limited with this stuff. maybe i hooked up something wrong on the coil ? what should the voltage be at the coil+ and should there be voltage at the coil neg? the wire that goes to the coil neg goes back to the ign module.
thanx for the help!!!