Help My 1992 F150 ,is making me crazy . Coil fires like a Tig tourch, i have never seen this before .It died right after i started it .i have replacrd coil. dis, pick up. and tryed a module form a mustang. mustang mod slowed down sparks . but it will fire non stop when key is on.Checked all fuses and relays . Anybody ever have this happen before?

 

What was the series of events that lead up to this issue? Were any parts changed before this happened? What about any rewiring or other accessories added?

The only way to fire a coil is to apply voltage to the positive side then release the energy by momentarily grounding the negative side. Something has to be acting as a "chopper" circuit to continuously fire off that coil without the engine turning over.

 

When something impossible is happening then 99% of the time it is a bad ground someplace.

 

First thanks 2 ,RLA2005 & subford. nothing has been changed recently. I suspect it has something to do with a streering coloum swap that my brouther did for me as i have a very bad back. when this happend i smelled a wire buring smell ,opened hood disconneted batt. searched all wireing and fuses found no burnt wires or blown fuses.but did find alot of sloppy work done by my bro. ive been working on cars trucks tractors gas and diesel for over 40 years. i will have to take dash apart to look further i think that were the trouble is.Truck is in between my 2 garages so a have only a short time to work before my back puts me down or the heat this time of year in so. Fl. im going to winch it up on car carrier and put inside today i hope.I have never seen a coil fire non stop before ,i did not think it was poss. Thanks again.

 

I was chasing the circuit that supplies voltage to that circuit. It does get routed through the ignition switch.

 

An arcing Ignition switch or the Ignition Switch plug can cause it to do that.