Loaded question

A LOADED QUESTION

Literally

Here is the scoop....

I've got a 1964 C-10 Pickup a that I built a couple years ago. I re wired the entire truck and haven't really had any major issues until recently....

First let me explain what I have, then I'll explain what it's doing....

I've got a 350 L-82 V-8 from a 1976 corvette, with an HEI distributor under the hood.

Standard Head lights and Tail lights

I'm running a Tuff Stuff 100 AMP alternator...

My volts at idle is about 13.5

With my head lights on it's about 12.5

When my electric cooling fan kicks on it drops to about 11 and then returns back up to 12.5 (Typical for any high load)

I also have 2 - 12" Rockforfosgate 12's and a couple 6x9's and a couple 4" speakers for music....

Now... everything had been working without a hitch until I switched from a sony to a kenwood head unit. I believe that the kenwood is pulling more then the sony.... or has a tighter voltage tolerance... because if I turn on my turn signal while driving the head until shuts off and then come right back on....

I'm assuming this is the load of the HEI+the head unit+the flasher load drops the voltage lower than the threshold required to keep the head unit on?

I'm wondering if I need to add a voltage stabilizer.... or what?

Any suggestions?

wiring

one thing you could check. turn signal flasher, if it is a heavy duty one ,it could be overloading the system.

Even tho the build is only a couple of years old, first thing I'd check would be grounds. One of the biggest culprits will be a proper ground on most electrical problems. Make sure all grounds are tight and right. My next stop with what your are telling us the problem is would be to check to see if proper relays were used on the circuits you speak of where needed. I don't see enough extra load with what you've told us to cause that normally. A bad connection or bad ground will cause all kinds of funky stuff to happen to an otherwise new and proper circuit.

Not sure I'm right, but the head should switch on and off every time the signal blinks, not just when it is first turned on?

shouldnt the alternator be reading about 14 to 14-1/2 max ? or at min. 13.5 to make it kick in to charge ? anything below 13 its not got the voltage to make it charge does it ? IDK ive been wrong 2 or 3 times today already

If you use the signal without the headlights on, does it also do it?

I'm wondering if you have something causing a bigger drain than just lights in the signal circuit. You didn't say what the voltage was when the signal is turned on.

Does it do it if you turn the wipers on instead of the signal?

What size amp is pushing your subs? And are you running a cap on the amp? I've had this problem in newer vehicles and its usually a bad ground or just too much amp for the charging system.

Wow... phase overload... Just Kidding

Thanks for all the response guys....

So I checked the flasher, it's a standard one, I replaced it with another just to see and still have the same issue..

As far as grounds.... That is very possible, the old truck chassis is the primary ground... when I first hooked everything up my turn signals wouldn't do anything then the next day they started working, so I will check that out.

Also in regards to the location of the flasher... I have it tied to the hot lead that feeds power to the switched side of the fuse block I installed, definitely looked like when I saw what I had done... so that may be part of the issue...

The voltage on my gauge sometimes is 14, when the truck is running and nothing else is active... ad lights it drops, add fan it drops but comes back up... with the stereo voltage dropping can be paced with the beat of the music. I don't have a capacitor for the 800 watt sub, so I may need to add one of those.

I am running a Tough Stuff 100 amp sex exciting 1 wire alternator I order from summit. The voltage always seemed a tad bit low when I looked at the gauge... but I thought maybe it was just me... about 13.5 if the high average it reads.

I have new battery cable and there is a chassis ground to the engine block, which I thought would be fine, but maybe I need to add one to the chassis itself... I think it currently gets to the chassis through the bolts of the motor mounts???

Looks like I've got some home work to do

Testing it out would be as easy as setting up several small pieces of wire with gator clips at both ends. Close to the starter, you can tie the frame, motor, and cab together just attaching the test wires there. I would also provide a bond between cab and bed and bed and frame somewhere in the rear. Just bond the different pieces and parts together and see if your problem still persists. If it still persists,,,that's not the issue and you can spend time in another direction. I would never trust body mounts to be the major bond/ground. Use a strap or old battery cable.

there is a piece of rubber that separates your motor from the frame so your motor is not hooked derectly to the frame. (cushion) so if that is your only ground .. maybe you will get lucky and this is your problem .
there should be a wire hooked to the cab from the back of engine , ( head maybe) kind of a direct ground to the cab , then like they have said one to the cab to the frame ..

When someone suggests checking your grounds, that usually means taking them off and checking for rust, corrosion or paint that is limiting the current capacity of the connection. On older vehicles run separate grounds for all accessories, it will save problems down the road.
suggestion: run your battery positive and ground directly to the starter.
It sounds like you may have lost a diode or two (or bad regulator) because a 100 amp alternator should not drop voltage as you are experiencing.
I would do a alternator draw test to see what amp output you are really getting.

As mentioned ground everything.Also the big wire on the back of alt,make sure its at least a 10 but 8 or 6 is better and the connection is good, and usually on the pos term on starter.

Update!

Thanks for all the replies!

I went and got the battery and alternator tested and they checked fine. I have verified this with my volt and amp meter, but wanted a second opinion. the components seem to be doing their job.....

so.....

I got to thinking [S over the weekend about when I rewired my truck and where the possible points of failure could be, and I ruled out everything that I replaced because it was all brand new... then I remembered that there was one thing I didn't replace when re-wiring the truck. The 'Thru-the-Wall' connector that connects power to the cab from the battery. I'm going to check that soon and see if that's where the issue is. It it the only thing that wasn't replaced, so I'm thinking possible corrosion or the conductivity of the old metal contacts have just met their time limit due to age/dust/vibrations/corrosion... etc...

I'll let you all know what I find out....

It the mean time I've got a body to swap! (50 chevy to the caprice chassis)
http://ratrodsrule.com/forum/showthread.php?t=31637

I was hoping you'd come back and say the problem had been found.

I'm thinking your right that the head unit has a tighter voltage tolerance. But, the wiper motor should draw harder at start up than 2 turn signal bulbs (not 100% sure of that). So if the head unit is not shutting off when the wipers are turned on, there must be something causing excessive drain in the turn signal circuit.

Grounds - Battery ground should connect to the motor at the starter. There should be a ground strap from the motor to the frame, and a ground strap from the motor to the body. And I suggest, a ground strap from the frame to the body also and from the frame to the bed.

Your stereo power feed maybe wired in at a bad place. You may need to run a separate fused wire directly to the battery for the stereo. The wire or connectors going to the fuse block may not be able to handle all the amps you're trying to pass through it.

Try this link for wire sizing:
http://www.bulkwire.com/wireresistance.asp

What company did you go through for the harness? Or did you make your own?

Sam_Fear said:

I was hoping you'd come back and say the problem had been found.

I'm thinking your right that the head unit has a tighter voltage tolerance. But, the wiper motor should draw harder at start up than 2 turn signal bulbs (not 100% sure of that). So if the head unit is not shutting off when the wipers are turned on, there must be something causing excessive drain in the turn signal circuit.

Grounds - Battery ground should connect to the motor at the starter. There should be a ground strap from the motor to the frame, and a ground strap from the motor to the body. And I suggest, a ground strap from the frame to the body also and from the frame to the bed.

Your stereo power feed maybe wired in at a bad place. You may need to run a separate fused wire directly to the battery for the stereo. The wire or connectors going to the fuse block may not be able to handle all the amps you're trying to pass through it.

Try this link for wire sizing:
http://www.bulkwire.com/wireresistance.asp

Click to expand...

Hollow65 said:

What company did you go through for the harness? Or did you make your own?

Click to expand...

thanks for that handy site Sam!

I think I forgot to mention I'm an electrical designer...lol... anywho I made a wire-harness after finding the old one on the truck had 'ghost' voltages and was not going to be usable.

Not the most beautiful thing in the world, but it has worked well... minus the one issue.. that I think I have narrowed down...

Nice work man. I ordered one from classic something... I forget, it wasn't a painless kit. But everywhere there is a ground connection I wire wheeled the frame and bolted it down then coated the connections with an epoxy. Worked really well. Also while I'm diagnosing stuff, I will use a piece of yellow tap to mark which wires I am currently messing with. That way I don't have to scrounge around under the dash or good to find them again. Lil stuff that saves time and headaches. When I have it all ready, I'll wrap the harness with a felt/tape. Looks clean.

The problem is fixed I think..... the column the P/O installed had switched power running 3 different ways unprotected and it over heated the wires...

Moved switched power to feed the fuse panel and now have 14 volts on gauge and the loads don't cause the radio to turn off anymore :-D