Intermittent voltage drop?

[00Silverado4x4]

mine never did it in my gmt800. only in my gmt900

 

It would seem to be more agressive in the 900s. I have several friends that have 800s like mine and some of them don't have the "bounce" and other noticed theirs to work like mine (started dropping after a period of years of driving).

[Gurrzt]

mine never did it in my gmt800. only in my gmt900

 

It would seem to be more agressive in the 900s. I have several friends that have 800s like mine and some of them don't have the "bounce" and other noticed theirs to work like mine (started dropping after a period of years of driving).

 

 

The older trucks (800) had a different alternator, charging system. My 2001 Z28 always charges per my electrical volt gauge.

[Big_D]

just unplug the module. my voltage would always drop well under 14 on the highway.. since i have a stereo, i want the full 14 all the time. after unplugging, thats how it stays.

 

ref:

http://www.performancetrucks.net/forums/gmt-900-trucks-188/gm-alternator-regulated-charging-control-488787/

[00Silverado4x4]

Got a picture of what we unplug to make this work? I don't really have a problem since I don't have high amp draw on my battery but my old school brain has never cared to see a voltmeter bounce like this does. "Used" to mean you had a problem, "now" you have to wait until you get an error code to tell you instead of using your gauges as your suppose to be able to.

[Big_D]

 

I just taped up the connectors and left them unplugged

[ujtruck]

if i see intermittent voltage drop, thats mean its less stress on engine, voltage regulator and better mpg

 

if Alternator loaded to max capacity, alternator itself can act as kind of engine brake (electro magnatic force) and thats how freight trains brakes work

 

http://www.youtube.com/watch?v=YFO2rcrshnU

[Doug_Scott]

if i see intermittent voltage drop, thats mean its less stress on engine, voltage regulator and better mpg

 

if Alternator loaded to max capacity, alternator itself can act as kind of engine brake (electro magnatic force) and thats how freight trains brakes work

 

http://www.youtube.com/watch?v=YFO2rcrshnU

 

 

Maybe I misunderstood, but, it sounds like the trains just dump the generated power from the brakes into resistors and convert it into heat. Why don't they take the power being generated and store it in batteries or some other storage device? They could use the power up on the next incline.

[corndoggy]

definitely seems like the original intent of this gauge in the dash was to be able to tell when you had the problem of your alternator not charging....

[Wires]

I'm just curious as to why my voltage starting "dropping" after a couple of years of driving. The voltmeter was always constant at ~14 volts then one day it just started dropping and raising and has ever since. I'm always scanning my gauges, pet peeve of mine. I found out it was normal operation but to not see it happen until after a couple of years driving???

 

 

If it just started happening, I'd suspect a bad battery. My battery died at year 1.5.

[silveradoprime]

This is completely normal on the 900's the alternator is run off the pcm and only charges the battery as needed. It helps to save a lil bit on mileage. I had a decent sized stereo set up in my Silverado running 3 amps, and mine would go to about 10.5V for a while and then back up, and never had an issue with the amps being starved of power.

[Brandon Elrod]

My 2012 will drop down in voltage it will be normal and then sometimes drop from 14 to 10 and lights will come on like I restarted the truck. Battery is 1 year old and alternator is 2 months old.. what could be the issue?

[dsr611]

23 hours ago, Brandon Elrod said:

My 2012 will drop down in voltage it will be normal and then sometimes drop from 14 to 10 and lights will come on like I restarted the truck. Battery is 1 year old and alternator is 2 months old.. what could be the issue?

Bad ground(s) or corrosion under the insulation on the battery cables (the cables on the GMT900 series are known to corrode under the insulation)