Some of us have experienced the dreaded immediate engine shut down while driving. That generally results in you immediately checking the infamous red wire. I got to do that last Sat. I was on my way to the East Coast Nationals of the National Street Rod Association in York PA. I got about 20 miles out and, the shut down happened. Pulled to the roadside, started checking everything, including the red wire, even though it was part of a new (3-4 yrs old) engine wire harness. Plenty of cranking, but no spark, no luck. Flatbed on the way!.
Since I tend to have some NOS stuff, I pulled a CDI box off the shelf and plugged it in....no change, plenty of cranking. Next tested coil, good. Had a new Unilite module on hand...no change, still plenty of cranking. Now I have less hair and bordering on crazy. Called a buddy two blocks away who is a real wiz with electronics. We get to testing from A to Z and find the ignition switch is a problem. Removed it, cleaned the connections, wires etc., but still,

all crank and no spark. Then I look at the CDI wire harness more closely for some reason, tucked up under the fender lip is a connection, but not just any connection. It had the fuse in it for the CDI. It had popped when resistance peaked in the ignition switch. So, in plain sight but no memory of it. Managed to run the battery down through all this testing, so it's on slow charge for road testing tomorrow. Getting new ignition switch on Mon.

 

I am an alumni of the school of sudden shutdown from an open in the bulkhead connector red wire pin. When that happens nothing on the car works except the horn. That is how you know and what you need to remember on the side of the road. In your case you seem to have been tripped up by a non-stock ignition system fuse. The ignition switch may have blown that fuse, but chances are just as good it didn't. Resistance does not blow fuses, the lack of it does.

Dan

 

Dan, After I looked at the red wire I checked everything else, had headlights etc, and cranked like a tornado wind. Dennis

 

Dennis,

I share Dan's concern that high resistance shouldn't have blown a fuse, as it would reduce current through the circuit, rather than increasing it. Leaves one to wonder what else might have caused a spike in current flow. I'm sure you'll be prepared with spare fuses in the glove box now. Might also consider a self-resetting circuit breaker instead?

Best of luck with it. Here's hoping it never happens again.

Live well,

SJW

 

I will be a Boy Scout about this! Dennis

 

So you’re going to help old ladies across the street while the car sits dead on the side of said street? 😀

 

I'll take them for a ride afterward! Dennis