Hi,
I'm new to the forum and know cars pretty well for the most part. I do my own maintenance on my car, but I'm not well versed in electrical problems and this isn't the car I usually work on but it should be simpler in theory given its age. The truck is a 1980 with a 20R. It will start and run via bump starting with the clutch, but it won't start normally. It acts like the battery is really dead, but I can't find what's draining it.
The other day it started like normal, it hadn't run in almost a month and it cranked and started after a few tries like usual. It drove and got warmed up and everything was normal but I stopped it and when I went to restart it just a few minutes later, nothing. The lights come on when the key is 1st put into the on position but when I go to actually crank it, everything dies. The lights go off, no buzzing, no turning over. Sometimes the lights come on dimly and sometimes they're bright, but when I go to start it everything goes off. I'm thinking it might be a bad connection to the battery or maybe a short in the ignition switch?

thanks for any help

 

will it even "click" over? is the starter solenoid working, getting signal? is the battery good? does it have enuf CCA?

try jump the solenoid and see if it clicks over. if not then its bad. if it does, then u have something in the ignition wiring. maybe starter relay getting hot and not responding.

 

If the battery is good I would check your terminals and posts at the battery make sure their not too corroded. Make sure your ground cable is properly secured to the chasis. Every now and then I have to file the corrosion off the terminals and posts until i see bare metal then apply some of this red battery terminal cream they sell at the auto store to keep the corrosion off. Eventually it comes back but Ive noticed that being an issue more often then anything else.

 

I ended up replacing the battery and now it fires right up. Thanks for the help. I find it kind of odd that the truck started after sitting for almost a month and then decided to stop holding a charge.

 

i had a similiar problem, pretty much the same symptoms. Then it would be fine for awhile then give me a few probs firing up again.

Ended up being the contacts in the starter. They were barely making contact then finally just werent touching at all anymore...found place that sold the contacts and swapped them out. Bout 12 bucks later and a lil time it fires up no prob now.