• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

alternator gauge bouncing back and forth

S

sonny martin

Well-Known Member
Local time
4:58 PM
Joined
Sep 13, 2017
Messages
50
Reaction score
31
Location
new albany in
65 dodge with 440 6 pack. alternator gauge bouncing back and forth. Put on new voltage regulator and had alternator checked .Alternator checked good. Car starting to miss and once
die. Any input would be most appreciated Thanks
 
Had a “good” alternator do this last summer. Put on a new one and it’s fine.
 
The alternator gage was bouncing on my 66 when the motor would be reved up. Traced it to a fried wire in the harness from the alternator and a couple terminals burned/melted in the bulkhead plug assemblies adjacent to one another. I think when the motor was reved and voltage/amperage increased it would short between the melted terminals. I read on here once that each time your alternator gage jumps, a short has just occurred. I think he was right. I removed the wire harness from the alternator to the firewall before I discovered the melted wire. It was just like the insulation slumped off to the side and left the copper conductors more or less exposed for the entire distance - not burned or an obvious mess - just a conductor nestled in a ribbon of melted insulation. The harness as installed placed the melted wire on the bottom and it just wasn't obvious without close examination. And it was a struggle getting some of the bulkhead plugs out of the bulkhead receiver - the plugs had fused with the bulkhead around the shorted terminals. They were a mess. Say hello to a new wiring harness.

Hopefully you have a lesser problem.
 
AR67GTX said:
The alternator gage was bouncing on my 66 when the motor would be reved up. Traced it to a fried wire in the harness from the alternator and a couple terminals burned/melted in the bulkhead plug assemblies adjacent to one another. I think when the motor was reved and voltage/amperage increased it would short between the melted terminals. I read on here once that each time your alternator gage jumps, a short has just occurred. I think he was right. I removed the wire harness from the alternator to the firewall before I discovered the melted wire. It was just like the insulation slumped off to the side and left the copper conductors more or less exposed for the entire distance - not burned or an obvious mess - just a conductor nestled in a ribbon of melted insulation. The harness as installed placed the melted wire on the bottom and it just wasn't obvious without close examination. And it was a struggle getting some of the bulkhead plugs out of the bulkhead receiver - the plugs had fused with the bulkhead around the shorted terminals. They were a mess. Say hello to a new wiring harness.

Hopefully you have a lesser problem.
Click to expand...
Thanks I appreciate the info. I'll look at the harness.
 
I had my amp gauge do the same thing. It was a broken winding wire in the alternator. Intermittent problems drive me crazy!
 
Nate S said:
Had a “good” alternator do this last summer. Put on a new one and it’s fine.
Click to expand...
did alternator gauge bounce around at idle and while driving ? Your saying your alternator tested good . Replacing alternator would be easy fix. I hate electrical problems. Thanks I appreciate feedback
 
sonny martin said:
did alternator gauge bounce around at idle and while driving ? Your saying your alternator tested good . Replacing alternator would be easy fix. I hate electrical problems. Thanks I appreciate feedback
Click to expand...
Yes. Battery still charged for the most part. Needle just bounced all the time. Swapped the regulator and no improvement. Then swapped to a rebuilt alternator and it became perfectly steady again.
 
Last edited:
update on gauge bouncing. found some wires in wiring harness where insulation had broken, put in new wiring harness, new starter relay, voltage regulator, ballast resistor .Wont start with key can jump with screw driver between starter and solenoid starts right up . ANY INPUT IS APPRECIATED. GETTING FRUSTRSTED
 
Did you do any replacement or other work under the dash? I would double check the bulkhead connections for the new harness sections and make sure none of the connections slipped out of place in the plugs because they were not clipped in securely and backed out.
 
You must log in or register to reply here.

Similar threads

C
Larger alternator amp/volt gauge help
Replies
10
Views
697
Nacho-RT74
Nacho-RT74
K
Alternator - Voltage Regulator Upgrade and Set Up Plan 1968 Coronet R/T
Replies
12
Views
2K
hunt2elk
hunt2elk
Snow Wolf
One wire alternator wiring question
2
Replies
36
Views
4K
Jam72
J
Potshot
Sanity check for charging system
Replies
14
Views
895
tonysrt
T
S
electronic voltage reg
Replies
4
Views
820
sonny martin
S
Auto Transport Service
Back
Top