no start/crank problem

[davie-blazin]

1990 k5 350/465
went out to start the truck today and it wouldnt start. jumped it, it was real slow to crank over but finally did. let it sit and idle for a bit. turned it off to fixe a vacuum leak, went back to start it and got nothing. tried jumping it and still nothing. if i put the key in with the door open im gettin the annoying buzzing but as soon as i move it to the on position i get nothing again, gauges dont move. i am gettin headlights and the horn to work. checked my grounds and 12v to the starter. the ignition switch is new and so is the battery. im completely lost on what else to be checkin for and what else to do. tried searchin but couldnt find anythin that would be the same problem. thnx in advace guys!

 

[gmc4cw]

how new is the battery? I have bought batteries that were dead and never took a good charge because of it.

your alternator is not designed to charge a dead battery, just run the electrical system and maintain a charge. if you are testing the batery across the terminals it may show a charge but have nothing behind it to crank the truck over.

PM ryoken, he knows a lot about electrical stuff and how to deal with joe pesci.

 

[davie-blazin]

the battery isnt even a week old. just confusing how i can start it up one minute and then the next, absolutely nothing

 

[mudbog42]

Hows your battery cables themselves, if they're corroded themselves or old they may not be getting the connection they need, you can try wiggling them a bit and see if it changes any. A bad connection can get your dash lights and guages, etc. to work but when you try to start it, no go and everything will go off.

I know from experience, hopefully this helps some

 

[Thunder]

Check to make sure the smaller 10 ga wire on the positive battery terminal is not corroded or broken and aslo bolted to the big batt terminal at the alternator. There should also be a 10 ga wire going. from the big terminal on the alt to the wireing harness by the firewall, That is the wire that powers Ign. Keyd starter, ECM and many other circuts. Any short or open circut in that wire will cause no start/power issues

 

[bigbadchev84]

Check Your Grounds!!!!

 

[davie-blazin]

grounds are all good, already checked them. ill check the alt wires tomorow, theyre the only thing i havent checked yet. thnx all for the input!

 

[colbystephens]

starter solenoid? that's a $15 gamble. try replacing it.

 

[davie-blazin]

well i went out today and did a little wire repair at the alt. it needed it anyways. it was still slow cranking so we pulled the starter off and bench tested it. the s terminal threading was loose and only making contact when it was forced over with the screwdriver. i tightened up the nut in there threw it back up and she cranked right over . thnx guys for all the help

 

[user]

I've got a mysterious weirdness, too. I can start the truck (a 1990 V1500 5.7 gas 4wd version) and drive it around, but when turn on the headlights, and then hit the highbeam switch, the engine dies and the lights go out. Multifunction malfunction? Wiring? Circuit Breaker (the problem goes away by itself after a while, especially if the battery gets too low to crank)? or short?