Stranded. Help!

[leadlobber7]

86 Silverado k30 4x4 454 TH400

Good morning all you repair gurus. I've got an issue that totally has me stumped. This morning I started my truck to go to work everything just fine, get about quarter of a mile from my house and my headlights, dash lights start flickering and the engine sounded like it was turning off then it came back on, the truck continued down the road about another hundred feet or so and then total loss of power! No dash lights headlights nothing, not even the dome light. I turned the key off, tried to crank the engine, nothing, no lights dome lights, nothing! Tried to put the truck in neutral to push it off of the road and I couldn't even get it into neutral, wouldn't come out of park. I sat there trying to think what to do, opened the door popped the hood, looked under the hood, couldn't see anything obvious. closed to Hood, tried to start the truck, fired up so I turn her back around and got my little car and headed to work.

I did recently change my ignition switch, following advice from a mechanic friend, As I had a similar situation happen except for one morning I went start the truck and the starter went to turn over, probably half a second of crank, then total lost power. So after some troubleshooting with test light found that there was no power to the hot connection junction terminal on the engine bay firewall, that was the advice I was given. That was a couple weeks ago so I don't know. Any ideas?

Update***

So I took you guys advice and drop the steering column and removed and reinstalled the ignition switch. I could only find 3 grounds. 1- from Battery negative to alternator mount. 2- from battery to chassis at Grill/radiator area. 3- from frame to chassis a grill/radiator area. ANY MORE GROUNDS TO LOOK AT? I removed, cleaned and reinstalled all 3 of those. I then started the truck up and was watching my small monitor that is part of my Holley sniper EFI kit that I installed 8 or so months ago. And all the sudden I seen my battery voltage box go red and start flashing at 18 + volts!! at the same time my dome light in the cab of my truck started to Flicker and the truck started to run really rough. Turned off the ignition. Then turned the key to ignition which fired up the electric fuel pump but dimmed my LED dome light at the same time. I then tried to turn the truck over with no luck not even a click. Right now all I have is power to my LED dome light. Even if I try to turn on my headlights everything goes black. Have no idea what's going on??

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[HotRodPC]

Sounds like you may have a voltage regulator gone rogue. 18+ Volts is to much. You'll start blowing fuses, breakers and fusible links. I have a feeling your Sniper isn't going to like that voltage either and you could possibly damage the ecm to the Sniper EFI also.

 

[leadlobber7]

Thanks sir. Any suggestions on where to begin looking? Voltage regulator.. Where abouts?

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[HotRodPC]

Voltage regulator is internal to the alternator. I'd connect a voltmeter on the back of the alternator to the big red lead, disconnect the battery while it's running and then see what voltage output the alternator is putting out.

 

[leadlobber7]

18.12v

Probably the reason that I had a sulfur smell underneath the hood the other day when I was checking out grounding. I did check the water level and had to add a bit.

I understand that being bad for the charging system but why would that make the truck run rough and eventually make the truck completely stall out going down the road after dimming All of the Lights?



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[HotRodPC]

Also, I wonder since the battery is 12V, take the belt off the alternator. Start it up and since it would be running off of the 12V battery and not the alternator, see how it runs. If everything is acting normal again, then I'd say that's the problem. Do keep in mind, with the belt off, I think that kills the water pump too, so you probably won't be able to let it run for more than 5-10 minutes or so or it'll start to get hot. But for purpose of seeing how the electronics are acting and process of elimination I think you can try it.

 

[HotRodPC]

18.12v

Probably the reason that I had a sulfur smell underneath the hood the other day when I was checking out grounding. I did check the water level and had to add a bit.

I understand that being bad for the charging system but why would that make the truck run rough and eventually make the truck completely stall out going down the road after dimming All of the Lights?



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Because your EFI ECM isn't liking the voltage, the ignition module isn't going to like the voltage and gonna say F you and not operate correctly. I'll assume mostly the EFI ECM. Somewhere in the 11.8-14.2 volt range everything should stay happy. Outside those paramaters not so much, and the further outside those parameters it'll be even worse and worse the further outside it gets.

 

[leadlobber7]

I remove the alternator belt, started up the truck it ran for about 5 seconds and then died

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[HotRodPC]

hmm, I would have expected it to have kept running off the 12v battery power. I'm going to be guessing at some of this since I'm not familiar with the Holly Sniper EFI and what it's ECM is looking for as far as inputs.

 

[leadlobber7]

Right now if I go out there and try to start it I open the door and my LED dome light is on in the inside of the truck I turn the key to accessory, my radio and my electric fuel pump turn on, turn the key everything goes black. If I open the door with the dome light on and try to turn on the headlights everything goes black as well. In the past couple months I changed out the ignition switch following advice from Napa and all was well for a couple weeks and then as per the first post stranded. While I was out there a few minutes ago I got my test light out and following everything going black I checked the inside of the firewall hot wire Junction point and had nothing then I heard some kind of noise under the hood and all the sudden the test light went from damn to almost normal. Waited a minute or so checked it again test light was good. Waited 5 minutes or so went out turn the key to accessory mode watch the monitor for my Holley sniper EFI and I have 11.9 volt.

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[HotRodPC]

That really sounds like a ground problem somewhere. It's got the classic symptoms of a ground problem anyway. Hopefully someone else will come in with some other ideas.

 

[leadlobber7]

Maybe you can shed some light on other grounds to look at other than the three that I found 1- from Battery negative to alternator mount 2- from Grill/radiator area bolt to battery and 3- from Grill/radiator area Bolt to frame. These three I have removed clean down to Bare Metal tightened fairly tight and sprayed with cold galv

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[yevgenievich]

Passenger side of firewall to engine block has a ground. Bad or dirty connection at the battery terminals.

 

[leadlobber7]

Okay so I think I figured it out. I started the battery chasing hot connections with my test light and my voltmeter. On my battery to starter cable the connection at the starter had some wiggle to it which was kind of odd, so I decided to take it apart and after I took the first nut and the two cables off of it I noticed that the nut holding the copper all thread in place was loose and the entire main connection bolt for the 4 gauge battery cable connection was not a quality connection at all. I tightened everything up made all my connections and fired the truck up. So far so good so I decided to take it for a spin for 15-20 minutes back around the area of my house and all is good!

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