I have posted this note on the electrical forum but it occurs to me that it may be a THING-only configuration:
After spending a week agonizing and bothering suppliers of COMPUFIRE and BLUE COILS I have discovered that my '73 Thing was producing no spark due to a BIG OLE CLUNKY LOOKING IN LINE FUSE located in the black wire that emerges from the right side of the engine compartment (probably a generator terminal), crosses over the engine and descends to plug into the coil + terminal. It was loose and was providing no voltage to the coil, fuel shutoff valve, elec choke valve, and others.
In troubleshooting I never considered this fuse as the problem because I would never think of installing a fuse in a line that would immediately shut down my engine. I thought it must be a wire going from the coil post to an accessory or such.
Does anyone else have a fuse such as this? Is it necessary? Should I remove it?
Thank you Glenn for the beautiful schematic.
The car's ancestry is a bit clouded. It was built in September '73 in Mexico with California pollution devices. It has a gas heater but it also has the protruding boxes over the air intakes in the rear fenders. It has a generator. This car doesn't know if it is a '73 or a '74.
It does appear that it has suffered some elec. surgery (separate horn switch, loose wires appearing from behind in the battery area, etc.
The black wire emerging from the harness tubing above the coil has no voltage. I now have 5 wires connected to the + coil post! Fuel shutoff solenoid, choke, disty, a black wire (must be the original power source), a mystery white green-striped wire from the harness, and the black fused wire I mentioned emerging from the darkness forward of the #1 cylinder.
Perhaps the best way to run these down is to disconnect the two unknown wires and see what is lost (if anything).
When it stops raining up here next week, I'll continue my exploration of this .
But back to my original question: should I cut out the fuse on this wire that is apparently powering the coil/disty circuit:?:
CapnDavy wrote:...But back to my original question: should I cut out the fuse on this wire that is apparently powering the coil/disty circuit:?:
That can't be answered until you sort out your wiring. As has been pointed out, in a "normal" car the wire w/inline fuseholder that goes from coil Term 15 to the RH side of the engine compartment is power to the backup light switch. Are you certain that the blown fuse you found was really the cause of your engine quitting and not just a coincidence?
There is no fuse protection for the coil power wire - if it shorts out (typically, someone connects the points wire to Term 15 instead of Term 1 and then switches the key on with the points shut) the wire from ignisiton switch to coil can fry. Some would prefer the potential liability of an inline fuseholder to experiencing that twice - but if used, it would be better placed up front and fitted with a 16A (if not 25A) fuse.
