Thread: More electrical gremlins!

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'56 Chevy Wagon. 350 sbc, starts and runs fine. AAW wiring harness. Previous installer with ZERO talent for doing wiring...
Started out for a car show this morning. Got about 10 miles and the car shuts off. Dead, nothing. No fuel pump, nothing.
Called AAA (again) and had it roll backed home. Push it in the garage and, just for grins, I hit the key... FIRES RIGHT UP!
So, I know I have a bad connection some where that is getting hot... Tomorrow I will be getting under the car to check the solenoid and ground connections. Any suggestions? I am to the point where I am going to rebuild the entire start and charging harnesses.
If you follow my wagon thread you know this is what I found last week while chasing gremlins.

Cutting it apart found this.

So this is what I am dealing with. I figure the only way to make this right is to redo everything.
Mark

Good luck with the search. I hate electrical problems like that. My plow truck came with one that drains the battery, haven't found it yet but put cutoff switch on battery.

I've seen coils open when they warm up. Seems it would be something with a pretty good current draw to get hot enough to open, but then close back as it cools....

No power, nothing at all means complete loss of circuit.

Those old chevys used the horn relay as a jumper terminal for several of the main feeds, if he duplicated that, it would be a good place to start.

If he made all connections that poorly, then you simply need to start at the battery, and check every connection.

Good luck

Ya' know, another thought is the ignition switch. If it's the original they can get pretty gunked up over time and start arcing internally, get hot and open, then be OK when cooled down. Might be worth a look.

My first thought is the battery cable, length, gauge and how close to the exhaust? That's the only thing I can think of that would shut the whole system down when hot and after cooling of would then work properly. Years ago I had that sort of problem on a 73 Caddy and that thing had a 4 ft run of around 6 gauge. I cured it with a similar length of 4 ought.

same thing with my 50 chevy if ignition switch was seeing more apms when engine was hot the switched side power fans even that relays were on the switch side of the relays .fuel pump .engine ignition. on the columm switch would over heat turn off . i needed to make other load wire in to the car then run it for added load. then ran a bank of relays on switch side of the columm switch to cut load amps runing threw columm switch now

Thanks for all of the help guys, VERY much appreciated!
Just to clarify, the harness is an American Autowire full harness. No horn relay so that is out of the picture. I will be doing exactly as you all have suggested. Going through EVERYTHING! I have to now just isolate the problem AND for my own piece of mind...
I have my work cut out for me but I have this week off so I will be getting into this full time the next few days. Wish me good crimps and no open circuits!
Mark

Worked on wiring on this car the whole week I was off. Pulled the battery and tray, pulled the starter and all of the starter/charge wires. The only thing that would shut down the entire system is a very hot 12V lead from the battery terminal on the starter to the fuse box. There is a 10ga wire with a fusible link so I replaced that with an 8ga. wire/fusible link.
Some of the stuff I found while pulling the wiring out.
A). Melted convolute tubing around the battery leads from the starter to the dash harness. The wires were very tight to the back corner of the pass. side cyl hd... This looked like it was getting pretty warm that close to the exhaust port.
B). The charge wire from the alternator ran in front of the engine, under the alt brkt, and then up over the intake manifold. I had to pry the convolute tubing off the heat riser on the intake. It had melted in place...
C). I pulled the temp sensor wire and found an "insulating washer", a fiber washer... under the ring terminal to sensor joint... Why would you want to "insulate" this connection? Just asking...
D). There was no dedicated frame ground (common practice on the tri-fives).
E). The body ground was a butt spliced 12ga wire.

This is a list of the changes made during the week.
1). Added a 12v distribution block to the firewall.
2). The above 8ga. wire routed from the starter battery terminal to the new 12v tap.
3). Shortened the 10ga. feed wire to the fuse block and routed it to the new tap.
4). Re-wired the alternator from a 1-wire to a true 3-wire. Ran 8ga. wire to the new 12v tap and routed a new sensor wire to the same tap.
5). Routed the alternator wire down to the frame rail and back to the firewall rather then over the engine.
6). Rebuilt the ground leads. Drilled and tapped a 5/16-18 hole on the top of the frame rail and routed a 2ga grd lead from the water pump, a 1/0 cable from the battery and a 4ga lead from the body to this bolt on the rail.
7). Pulled the cluster and replaced a bad LED turn signal lamp.
7a). During the LED swap I get the turn signal indicators working but they are backwards... I find the signal wires are reversed in the dash connector. Swap those to the correct pins and the indicators work correctly now.
8). Unplug the NS and B/U lamp harness from the switch down at the trans. Install a pair of relays under the dash and wire in new switches on the shifter. I have some adjusting to do on the NS switch but the car now starts every time and we have B/U lamps!
That was my week, how was yours?
Mark

Here a few pics of the work I did.
The new ground zero...

New 2ga. cable to the front of the engine.

New neg batt terminal and 1/0 grd cable. (I replaced the wing nut with a hex when the work was done.)

This was the body ground as I found it...

This is the new 4ga body ground.

The 12v distribution point on the firewall.

Building the new 8ga. lead down to the starter. I made this a bit longer then the original so I could route it away from the cylinder head and header pipe. I use copper butt splice connectors and solder the joints.

Wrapped with self-fusing tape.

And then heat shrink.

Hanging the NS and B/U lamp solenoids under the dash. These are right behind the instrument cluster and easy to access with the cluster removed.

This is the 12v switched power lead for the back up lamps... As I found it. I cut it short right above the break and hard wired it into the relay. Did the same for the purple NS Switch wires and the green lead for the B/U lamps.

I wired the relays thru these two micro switches the attach to the shifter. I wired them as negative ground to switch them on. The switches are wired to a common ground on the shifter and have two wires that run up the relays.

All wired and tested. They work great and the car starts right up every time now...

HOPEFULLY all of this work will payoff with a more trustworthy electrical system. I sure hope so...
Mark

Well, had the wagon out this past Saturday. Maiden voyage with the new wiring. Did a small local car show and had a good day. The car ran well, didn't leave us stranded and got a top 25 at the show!

The new wiring seems to have done the job. The car starts every time, the volt meter stays steady at 14 volts, even with the air on, and she runs down the road at about 170, temp wise.
She does wander a bit going down the road so I think I will have the steering box checked out and get her aligned. Probably too much toe out so that needs to be addressed before I do too many trips with her.
Mark

I'm happy to hear that you got that mess sorted out; whew - that was a pretty good mess of gremlins.

toe out????