Voltage read on dash?

So I start my truck this morning no problems at all but my factory volt read on my dash wouldnt move past about 10-11 and the red battery indicator light on my dash wouldn't turn off. So I pop the hood and everything is good as far as alternator and battery connections go so I turned it off and back on with the same results. Once I started driving to work the voltage gauge slowly climbed up to 14 where it has always been.
Should I be worried? How accurate is that factory volt gauge? I'm out of town until Tuesday so it's got me more worried than I usually would be.

I would say maybe the ALT is weak.

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My truck does that, and has been since I have had it (about 8 years now). It seems to be related to the charge of the batteries. If they are way down from lots of cranking or lots of glowplug time, the gauge will stay down lower longer. Eventually like yours, it will slowly climb back up. Like it's "filling" the batteries. Like I said my truck has always done this, no problems.

I finally got my voltage gauge wired into my truck, I noticed that before I start it reads 12v, as I cycle glow plugs it draws down a couple of volts, same with cranking. After it starts it stays at 12v for about 30 seconds to a minute when it then pops up to 14v.

Mine has new batteries and starter. Alternator is old but has always functioned well.


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Proper charging can be affected by: 1) Alternator belt tension. Is it slipping? 2) Health of the batteries. Are both taking and holding a charge properly? 3) Are the battery cables and connections in good condition. Check them with a ohm meter for high resistance. You can use the second table here as a guide. 4) What is the condition of the alternator? Have it tested by a reputable shop if you are not sure.

I was having charging problems too. Low voltage, alternator light intermittently glowing, batteries not charging, etc. Since last August I have upgraded to a 3G alternator with new alternator belt after my 1G alternator wore out. Replaced both batteries. Replaced the TECA relay for my E4OD. The old relay was sticking closed and draining the batteries. Cleaned and sealed all the battery cable connections. This next spring I will replace all of my battery cables because they are reading 3-5 ohms resistance even after cleaning the connections and their insulation is cracked allowing internal corrosion to build up.

Your may not need to do all of these things. I had to because it had been that many years since I last had to replace any of it. If it ain't broke I don't fix it. With the age of my truck though, when something breaks it usually means I have to fix several things at once. It's been a good ole truck and I will drive it till I can't fix it any more. Good luck.

I have noticed in both of my diesel trucks that the voltage does not jump to 14v right after starting. It takes a few minutes before I see 14v. I think this is normal.

Old 1g will do that, mines does that if I idle up to like 1500 it climbs to 14 like normal and stays there. Battery's condition plays a factor, check belt tension and condition as well and make sure it's not contaminated with oil or water. The v belt trucks will almost always have a flappy alt belt it's juSt becaus even how long the belt is even when the tension is correct. when first starting your truck make sure no high current drawing accessories are in like heater fan are on let it run for 30 seconds before turning them on to let alternator catch up from starting the truck

DaveBen said:

I have noticed in both of my diesel trucks that the voltage does not jump to 14v right after starting. It takes a few minutes before I see 14v. I think this is normal.

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I know for sure it's normal on the PSD.
But what would concern me is the actual battery light coming on. I think my 88 did that also. But would sometimes come on while driving. Can't recall if I ever messed with it.

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Turns out it was a dead alternator. It was the original one also. I can't believe it lasted that damn long.

Sounds like it's time for a 3G upgrade.

The one I bought is a 130 amp alternator.
It's all I need. Isn't that the 3 g?

Your truck has the 3g stock, all serp trucks had it.

Lol

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I apologize for my C.R.S. ( Can't Remember Stuff ) syndrome causing me to forget when the trucks went stock with the 3G serpentine setup.