I have an 86 k5. I just got it and took it out one night in the woods. That night I started having problems. After shutting off the motor, and when trying to crank it back up, there was a clicking noise from under the hood.(My dad later while under the truck said it was coming from the starter.) She would turn over though after some persistence.
The next day, I had to hook up the battery to a charger to get the truck to fire up. I drove to a buddies and had to jump the truck off his to get it to run again. Now however, the boost of electricity wont fire the truck up. So I took the starter out and took it to auto zone and the starter is good. I put the starter back in and now there isn't any clicking at all. Nothing happens when I turn the key over, and the truck still has power (the radio/ lights work)
Ive been told that the starter will click if there is a short in the wiring. I was honestly hoping the starter was bad so I could spend $55 and be done with it. However that is not the case and I have no clue why the thing wont run.
My Neighbor is going to bring a power probe to see if we cant find where this thing is shortin out.
Also, I broke what looks like a sensor that plugs into the bottom of the motor. I dont know where it leads or what it is, it is right by the starter though. The housing for the starter broke it out as I was trying to get the thing out the first time. Any one have any idea what that could be?
I know theres some guys on here that know a lot about these trucks. I dont, Im trying to learn though. Any help is greatly appreciated.

 

found out that the sensor is the oil pressure sensor.
Got a power probe to the starter, its getting 12 volts. The positive wired maybe grounding out because the cover is cut. Lost a bolt for the ignition wire lol. Gotta go get that bolt and some tape. Gonna put in the starter tomorrow and we'll see what happens. I also drained the oil; there was no gas in the oil so the motor aint hydrolocked. Once the wiring is sound I dont see why it shouldnt crank... I hope I can keep my faith in Chevy after tomorrows endeavor.

 

Try cleaning all the grounds including your battery terminals even the possitive. Just cause you got 12v doesn't mean you got the amps

 

are you sure it isnt the knock sensor as it is located right in front of the starter, should have a round white connector kind of like a bowl on it.

 

It could be the knock sensor, it has the white "bowl" which i broke off by accident. What does the knock sensor do?
I cleaned all the terminals on the battery yesterday. I am about to cover the positive wire that is exposed with tape and see if I cant get her running. If not, cleaning the grounds is a good idea.

 

the knock sensor allows the engine to run with the ignition timing as far advanced as possible. The computer will continue to advance the timing until the knock sensor detects pinging. At that point the computer retards the ignition timing just enough for the pinging to stop.

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