Volts low at start

Reply Subscribe

Thread Tools

Search this Thread

Jun 3, 2014 | 08:07 PM

#16

KDAVID1

Thread Starter

Logistics Pro

Joined: Feb 2013

Posts: 4,073

Likes: 5

From: TX

Quote:

Originally Posted by BLADE35

10.5 not bad if the gauge updated during the actual crank

you do probably have a battery cell going down

Mine usually gets to 12.68volts within 6-10seconds after crank at Idle Temp kinda plays

Mine was a little slow to get up but was good once I started off. Not sure how old my batts are--but been planning on changing them soon anyway--couldn't hurt I suppose.

Jun 3, 2014 | 08:52 PM

#17

mhoefer

Postmaster

Joined: Jan 2005

Posts: 4,424

Likes: 12

From: BC Canada

I am at 12.8 volts seconds after start, a few more seconds, am at 13.2. Even in the cold. I suspect both batteries, bad cells, perhaps alternator. How many amps is your alternator.? Before going to the 230 amp alternator, I had a 140 and hit 12.8 in seconds. Anything below, you have bad batteries, if it doesn't climb up over 12.8 in seconds, that alternator is not doing much.

Jun 3, 2014 | 09:03 PM

#18

04badford

Lead Driver

Joined: Sep 2012

Posts: 7,830

Likes: 96

From: Manteca,Ca

One good test on the Alternator is to have engine warm , turn everything on lights, radio, AC fan on high, ETC, you don't want anything below 13.3 via scan gauge or take it out and do a load test

Jun 3, 2014 | 09:11 PM

#19

KDAVID1

Thread Starter

Logistics Pro

Joined: Feb 2013

Posts: 4,073

Likes: 5

From: TX

pretty sure its stock alt.

previous to current events it would stay above 12 when starting--prolly gonna change batteries and see how it goes--then on to alt if need be. Would love to go with one of the big alts but don't want to do the cable swap just yet so will more than likely go with a 140. I'm not drawing a load with accessories anyway so that will help. I'ts kinda funny--since I've owned the truck before I start it I make sure everything is off--ac, lights, radio, etc. I turn the scangauge on then turn the key. The wife just shacks her head

oh yeah--I have done the turn everything on once running at idle once warmed up and the volts stays up pretty well--but can't remember if it went below 13.3. I'm thinking 13.1 but will verify that tomorrow.

Jun 3, 2014 | 09:15 PM

#20

04badford

Lead Driver

Joined: Sep 2012

Posts: 7,830

Likes: 96

From: Manteca,Ca

load test the Batterys separate they still may be good , eather way the Alt if not good will kill the new Batts and FICM

Jun 3, 2014 | 09:18 PM

#21

mhoefer

Postmaster

Joined: Jan 2005

Posts: 4,424

Likes: 12

From: BC Canada

Do you have a hydrometer? If you check the specific gravity of each cell of each battery, that will point you in the right direction. They have to be fully charged and disconnected on a bench, but it will tell you if you really need the batteries, or you need am alternator. My 140 was original and lasted 100k miles and 2 sets of batteries, 8 years. A new 140 and overdrive pulley would be a good compromise if not a bigger amp being affordable at the time. I get the same rolling eyes when I go through the start up routines, it's not a jet, but it is my TRUCK!

Jun 3, 2014 | 09:18 PM

#22

KDAVID1

Thread Starter

Logistics Pro

Joined: Feb 2013

Posts: 4,073

Likes: 5

From: TX

Quote:

Originally Posted by 04badford

load test the Batterys separate they still may be good , eather way the Alt if not good will kill the new Batts and FICM

agreed

Jun 3, 2014 | 09:37 PM

#23

KDAVID1

Thread Starter

Logistics Pro

Joined: Feb 2013

Posts: 4,073

Likes: 5

From: TX

Quote:

Originally Posted by mhoefer

I don't have a hydrometer--but will get the checked for sure. HAHA--yeah--I've got my wife scared to even sit in the drivers seat. She see's what all I go through and thinks if you don't do everything exactly the thing will blow up lol. She refuses to drive it--more seat time for me