-Losing voltage as car is running? HELP?

-
1fast340dart

1fast340dart

Member
Joined
Jun 29, 2010
Messages
8
Reaction score
0
Location
Roanoke,Va
Hello,
needing some advice..i have a 1972 dodge dart factory 318 all orginal as far as drive train goes,motor was taking out during restoration,problem started accurin upon completion,lights flickers during night driving,blowing Multiple fuses under the dash,etc. ive recently replaced battery,every fuse in the fusebox underdash,new altinator,balance resistor.checked my grounds etc...im still loosing voltage though any suggestions ?????? thanks
 
Regarding the losing voltage I would say maybe the amp gauge or dirty connections at the firewall terminal block. Where are you checking voltage at?
To trouble shoot it you may want to start checking voltage at alterator with that car running then check at the firewall terminal block at in and out for the alternator wires and then at the battery.

Blowing fuses would be a short, tell us more about the fuses do they blow right away and what circuits? Thinking a short may be your problem are the flickering lights blowing the light fuse during driving?
 
only fuses blowin in the fusebox would be stuff like signal fuse,instrument panel fuse..Regardin the terminal block im thinkin thats where my big problem falls,is there anyway JUSt to replace the block it self with-out having to rewire the whole car ?
 
....And could the AMP guage be the main cause in loosing voltage ? maybe something is crossed causing this ?????
 
yeahh,the ignition swith was actually the 1st thing i replaced,solved the light flickering problem,but later just returned..
 
I'm not quite sure what you mean regarding losing voltage if you check the battery with the car running it should have 13.6 to about 14.2 volts with the car running. I'm no expert with car electrical but I did trouble shoot my 65 Barracuda by checking the voltage at the alternator the wire block on the firewall the regulator and the battery

I found the battery was only at 12 volts with car running. So I went and check voltage at back of alternator and it was was 14.2v

I then checked the heavy gauge power wire going in to the car at the firewall connector that comes off the alternator and it had 14.2v

However when I checked the heavy gauge wire that comes out of firewall from amp gauge to charge battery I only had slightly over 12v

So I just narrowed the problem down to the firewall bulkhead connections or the amp gauge. My problem was the amp gauge.

You really just need to get a wiring diagram and start check voltage along the main charging circuit. to find a voltage drop or non charging problem.


The blowing fuses would be completely unrelated to the above voltage problem in my opinion. This could be a result of shorted wires (bare wire touching ground) or bad light bulb socket, light bulb, ect.

Good luck hopefully with a little more checking and a detail description of your problem we can figure out a solution to your problem. Lots of guys better than me with this electrical stuff but maybe I have given you a few ideals for narrowing down the search for your cars problem.
 
im thinking we've have/had the same problem,so the AMP guage as a possibilitly of being bad or not rewired correctly could be my problem ??? another thing car will run fine until you stop,then try to restart=nothing dead as dead gets
 
1fast340dart said:
im thinking we've have/had the same problem,so the AMP guage as a possibilitly of being bad or not rewired correctly could be my problem ??? another thing car will run fine until you stop,then try to restart=nothing dead as dead gets
Click to expand...

My car would have really dime lights at idle the signals would not work sometimes. The car would stall sometimes and sometimes would not even restart or even turn over probablly because the battery was dieing.

Make sure you disconnect battery when working on these wire they have power all the time

I pulled the dash panel cleaned the amp gauge wires and reinstalled then check voltage with car running at both sides and found large voltage drop at gauge. So I bypassed gauge by connecting the wires together and taping them up. It is like a completly different car in the way it runs starts and lights work including the signals and voltage at battery now matches the back of alternator.

I still need to send in the gauge to be repaired or just leave it bypassed. with no amp gauge.
 
you can bypass the wire from the bulkhead connector by running a heavy gauge wire from the battery terminal on the alternetor directly to the positive on the battery. this will completely bypass the amp gauge. I had to do this on my car because my charging system was doing the exact same thing. Found out later it was the post on the ammeter gauge itself in the dash cluster, broken connector at the gauge. So I just left the bypass wire in place until I replaced the gauge and the car charged fine. Hope this helps.
 
1fast340dart, swapping parts is the wrong way to try and fix a problem. If you are going to own an old car you need to own and get real comfortable using a multimeter and reading the cars wiring diagrams to trouble shoot electrical problems. Zhandful took the right approach and it likely only took him 5 minutes to narrow it down to the bulkhead or amp gauge. You need to do the same thing to understand if it's a lose in the wiring or one of the parts is not working.

You say you checked the grounds. The alternator case has to be grounded, if you repainted the engine and all the brackets and reused the orignal bolts that gorund may be bad. Same for the voltage regulator, it grounds through the case, new paint old screws and you have the makings for a poor ground there. Also, just becuase you put in new parts does not mean the parts are good. If you make the same measurements as zhandfull and they are all the same within a 1/2 volt then the issue is with the alternator or voltage regulator, if they are not you can zero in on it like he did.
 
I just had the exact same issue. It was a short with the ignition switch.
 
There is also a voltage regulator for the instrument cluster, I was having power issues, and flickering lights and the battery not recharging. I luckily had just bought a new gauge cluster, put everything in and it seems to be working fine now. But that part I think is about $47 at O'riellys or online you can get a electronic one for about $50, I cannot remember the company. But I hadn't blown any fuses, just had issues with my gas and water gauges.
 
moparornocar72 said:
I would guess something is touching or is rubbing against another wire.
Click to expand...

Exactly what my issue was. Was a pain to pinpoint without a multimeter and a lot of patience and a key turning monkey. Poor dude drank a six pack listening to me curse non-stop for 3 hours. Turned out to be a couple broken wires tap dancing on eachother causing a dead short.
 
You must log in or register to reply here.
-

Back
Top