wheelieking71

thank you guys, that is exactly what i was thinking (and just posted over on RCC, bad battery that is). i went over the main power system last night and didnt see anything. but i do agree that since it did it when the FSS was hot-wired basically straight to the battery, if its not a main power wire, it has to be the battery. couple questions though: wouldnt the alternator pick up the slack? any ideas what would cause the volt gauge to freak like that at low idle?

Rampage1967

Check all your ground connections. I have seen bad grounds do things like that on other vehicles. Engine movement will make & break the connection.

wheelieking71

okay, for the sake of my own sanity. lets walk through my upgraded electrical. first up, battery relocated under passenger bed-side:



all connections and terminals checked out and tight. next up, nice short ground to passenger frame rail:



B+ 12v comes over the rail, and runs well secured and protected straight to the hot post on the starter:







lots of plastic loom, electrical-tape, and adell-clamps. i looked it over real good and see no issues, or evidence of arcing. (im sure if the 2/0 was shorting there would be some nice weld spatter somewhere!) then we go to the alternator. not much to see, but the new 4ga is connected to the hot post, and tight:



this runs up and accross the firewall, then dives down and meets the 2/0 at the starter hot post:



the second 4ga down there runs right back up the firewall, and over the drivers-side inner fender to power the fuse panels. you can see it looping back to the forward panels hot post here:



and thats about it. i think the next step is to rule out the battery. if it goes away with a different battery YAY! if not i will then pull my hair out LOL.

DodgeFreak

Is it worse with more electrical stuff on? I know my truck will idle with out the battery hooked up but not sure what it'd do with a big load on it.

Alec

Do you have a 2/0 cable running from the frame to the engine block? Were it me, I would have 2/0 copper from the battery to a point on the block near the starter, as well as the bond to the frame, and then 4ga to the cab for the ground side.

If you don't have the 2/0 from the block to the frame, then who knows what has been seeing back voltage when you start the truck -- if you do have that covered, I'm thinking an intermittent short in the circuit to the FSS.

wheelieking71

Yes, there ia a 2/0 ground from the block to the same frame-rail as the battery. There is also a heavy ground strap from the head to the core-support. And another from the cab to the frame. I was just screwing around again just now, and noticed, when it does it there is a huge cloud of black smoke. It is definitely throttle, or RPM related. Because there is nothing electrical hooked to the throttle. I know it almost has to be electrical. But it seems the only time it does it is very heavy throttle, at very low RPM. Im stumped!

wheelieking71

I think I may need to actually gut the FSS to rule out fuel. It just feels like fuel.

wheelieking71

Its not the voltage regulator. I had an extra, so I swapped it. Its not my wiring for the overdrive solonoid (I was grabbing at straws for the correllation between throttle input, and the issue. The solonoid is electric) I disabled it. Still does it on both counts. Swapping the ignition switch next..........

tech-eh

im so glad to here your fuel pressure is not an issue.... could something that is lose inside the alternator it would just take a small screw or the inside of starter solenoid could be lose and moving under load also one of the bigger hd cables could be bad on the inside and look fine on the out side try wiggling each one they are created when they switch over cable runs they are called hot spots and it happens hope some of this helps

tech-eh

ps ya I know the alt and the starter look new

j_martin

Ain't no way a fuel problem will make the headlights blink.....

Somewhere a battery connection, or the battery itself is opening up. At low RPM, the alternator doesn't pick up the slack. At high RPM, it might.

One of them pretty connections is oxidized a little more than you think.

If you don't believe me, stick a lawn mower battery under the hood and hot wire the FSS with it. The lights will blink and the engine won't stumble.

BC847

A reminder to everyone, we have a No Profanity rule here in the DTR.

wheelieking71

sorry BC, i will try and watch my *****'s. and thanks for another great tip j_martin! i totally believe you. im just getting frustrated. im supposed to be working on my brakes, pan-hard bar, steering stabilizer, body-work/doors. not this crazy drivabilty issue. i will try the extra battery for the FSS tomorrow. thats brilliant! i was thinking of gutting the FSS, then starting it up, and disconnecting the battery altogether and seeing what it does. that would totally eliminate the battery, and the engine from the electrical system. i have an extra, known good battery sitting here. maybe tomorrow i will stop and grab a set of top-post to stud terminals, and just swap the battery. i got half-way through the ignition switch swap, and realized that i had previously twisted off the needed size safety torx bit in my set, so that stopped me in my tracks there. and, after i swapped out the voltage regulator, and noticed the screws werent very tight, i went over all the main grounds. pulled the bolts, scotch-brited the metal, and retightened. everything looked good. issue remained. i hate just swapping parts, because i like to think of myself as a decent mechanic. at least on my own stuff. and i know thats not the right way to go about fixing things. but i am really out of my realm here. and i am glad i have lots of known good spare parts. at least im not out buying new stuff to replace parts that are not bad LOL. and i am glad for DTR! i really appreciate all the help/advice guys! ALOT

DodgeFreak

Theres nothing wrong about swapping parts.....to an extent. electrical is one of the hardest areas to diagnose a problem. sometimes the best way and easiest\cheapest is to start in a systematically order and eleminate each part.

j_martin

I wouldn't run it without a battery hooked up. Without regulation the alternator will put out near 100V. If there's a battery in the circuit, it holds it down to 15 or so. Without it, everything electrical that's on is instantly wiped out if the regulator even blinks.

If you have another battery, even a smaller one, you could swap it out.

What about crimped connections?

Another possible test:
Turn on headlights, heater, and anything else that'll draw power.
Wait a few minutes.
Check all connections with an infrared thermometer.

Is there any possibility that the engine rocking in the mounts is allowing something that shouldn't to contact the frame?

From where does the fusible link delete get it's supply? Failure there would cause this scene.