The past 2 months have been tortuous for me. Wiped a lobe on my cam during break-in last month. I got that a new Lunati cam to replace the original one and just got it all buttoned up again this weekend. I wheel it out into the driveway to do the break-in, turn the key, and....nothing. No gauges, no lights on the gauge console, no fans turning, nothing. I pull out the meter and the battery is ok, same voltage up to the starter motor, but when I get over to the aleternator I only get a small blip of maybe 1V on the main red terminal and the clip into the alternator. I disconnect the clip and the main +12V line to the alternator and remeasure, thinking maybe the alt fried some how and I still get nothing on the meter.

The crazy part is that after fiddling for 45 minutes I wheel it back into the garage out of frustration and remember I wanted to take one more measurement with the ignition key turned on and was the batt being drawn down. Turn the key and lo, this time, lights and fans, but it's too late to start it and break it in. So, this afternoon I wheel it out again and get the motor to turn over and run for maybe 3 seconds and blam, the electrical disappears just as before. This time in spite of all my poking prodding, flexing wires I can't get it back.

I'm at a complete loss as to what to do next to debug this thing. The crazy thing is that before I tore down the motor to replace the cam, it never gave me this trouble. I don't know what gives but this is really irritating me!

Ideas and suggestions much appreciated.

 

I believe there is a fuse link (soft rubber coated wire) at the starter that powers the accessories and runs to the alternator...check that first...

 

And if that's ok, go up that wiring harness to the top of the firewall look at the connector. i had a problem with it before...same as you...no power

 

I'd bet its a fuseable link.

 

I just checked and looks like the fusible link was removed. There is a splice about 12 inches back from the point where it connects to the +BAT at the starter.

Where on the firewall am I looking for the connector? This thing is hard to trace given it disappears into harness wrap.

 

yeah, that harness wrap, go up it to the big connector 6-8 wire's in it...

 

Check the battery terminals on both ends. A bad connection will go dead when loaded. It can burn through the corrosion sometimes.

I went through this with positive then negative. Negative tested fine but when jumpered it worked.

Since its the whole car seems likely to be the battery terminals or the other end of them.
Starter has 2. Battery cable and positive feed to the cars interior. That connector is the feed for it.

 

The harness connector is a good tip...mine was corroded and sometimes would not start...also,tweak the connector "holder" slightly to hold it together...

 

Hi,
I had a similar thing happen with my first '80 a few years back. It turned out to be a bad ground between the battery and the frame. When I pulled that cable out, the part of the cable that was outside of the battery tub was about twice as thick as the part that was inside the tub. That was because the part of the cable that was outside was so corroded, it had bulged out the insulation with the metal decay. When I cut the cable to see what it looked like inside, it was basically dust. I don't know how any electrons moved through the thing.

I hope that helps. My car acted similar to what you're describing, but not exactly. If it started, it was fine - it wouldn't stall. Oher than that it sounds similar. The dome lights, fans, clock, radio display, etc. would work until I turned the key. When I hit the starter, the starter would maybe turn a (very) little, maybe not, but the car would go totally dead either way - no lights, fans, radio display, no familiar rewind clunk of the clock. After a few minutes of hair pulling, fuse checking, and asking WTF? the lights, etc would magically just come back on. When "life" came back, it might die again after hitting the starter, it might start. It eventually wouldn't start at all until that ground cable got swapped out for one with metal in it.

So, check for clean battery and ground cable contacts. Check for cables that are made of nothing but oxidized copper dust. Try the cable between the engine and the frame too.

Good luck,
jcd - Red '80 L-82

 

I found my electrical problem tonight. Took some poking and prodding to get to the source but it all comes down to where the +BAT comes out of the main harness along the firewall from the starter to the connector where it continues to the alternator. It took me a little while to find it since on my '77 this is under the power booster.....a tough place to work.

I took the connector apart and the ends are not lost but they are corroded and need some help. If I flex the connector around the power will come and go. It's not the wires because I put the meter on the plug directly and then wiggled the wire and it was still solid. Any ideas on how to clean the connectors on each end? Sand paper would be very hard to get in there but if that's what it comes down to so, be it.