View Full Version : Short circuit

01-10-12, 04:09 PM
A few weeks ago, I left Paris with my Ram fully packed with all the needed equipment for a drag race week end on Saint Yan Airport, approximately 200 miles from my home. The car was running almost smothly and perfectly, the weather was fine but suddenly, after driving only 5 miles, the engine stopped and white smoke came out of the hood.
I immediatly switched ignition key and battery off, stopped the car in emergency on the side of the motorway and jumped out of the car with one of my fire extinguishers. I waited a few seconds before opening the hood, saw that smoke dissipated spontaneously, opened the hood. I noticed that a white wire going from the firewall had its insulator badly melted 'green arrow).
I took some insulator tape that was in my tool box and isolated this wire, this was not easy because lots of trucks were passing really close and fast to me and my Cobra on the side of the road.
I put back the battery switch, turned the ignition key and the engine started without hesitation. But after half a mile, the engine stopped again with even more smoke coming from the hood and below the dashboard. I turned everything off, and stopped the car on the side of the dense trafic highway. The black insulator tape I used also melted!
It was not possible for me to search further for the problem due to trafic conditions, I called to be towed in my garage where I could work quietly. Many Euros later ( 200 Euros for 5 miles of towing) and some hours later, I inspected the electrical system carefully.
The guilty wire was going to the balast resistor of the ignition coil(green arrow). At first sight, everything seemed normal. I checked the resistor balast which was not broken, with a correct voltage but touching the resistor, I felt it was moving freely in its metallic bracket (pink arrow). So, while driving, with the engine vibrations, one of its terminal (blue arrows) made the short circuit with the bracket attached to the engine. Usually, the balast resistor is held against its aluminium support by a spring-like metal leaf and this little leaf spring had diseappeared ( old, broken or what?)which explained that the resistor was freely moving.

Balast resistor, wire, ignition switch changed and also......a fuse added in this circuit. It could have been a major disaster....

01-10-12, 05:18 PM
Cover all the wires in split conduit too, it's very cheap stuff.


01-10-12, 05:37 PM
That which does not kill the car makes it stronger.

Well done on sorting it out and as you said it could have been a lot worse.

Did you get to the event?


01-10-12, 05:47 PM
well done for sorting, someone was looking after you that day , could have been a whole lot worse Dave.

02-10-12, 02:32 PM
No, I unfortunately did not went to the event because I needed 3 days to get the parts.I hope 2013 will be better even if "13" is not a lucky number..