I don't remeber this happening when I got the truck in September but I noticed this wierd problem Friday, When I start the truck up it takes a minute or so for the alt. to get to full voltage. I put a DVOM on it and after a start it rises slowly until it reached the 14.5 volts. Has anybody else seen this? Or am I heading for the dealer? I did check all the conections and they are clean and tight.

Thanks for the help.

Remember..Your glow plugs take lots of power..........

I don't remeber this happening when I got the truck in September but I noticed this wierd problem Friday, When I start the truck up it takes a minute or so for the alt. to get to full voltage. I put a DVOM on it and after a start it rises slowly until it reached the 14.5 volts. Has anybody else seen this? Or am I heading for the dealer? I did check all the conections and they are clean and tight.

Thanks for the help.

I think its normal. Mine does that too. I have heard of others experiencing this also.

I think its normal. Mine does that too. I have heard of others experiencing this also.

Noticed mine start at 5V and slowly came up to 13.5 after a few seconds. I would only worry if it stayed below 12-13Volts for an extended period.

Remember..Your glow plugs take lots of power..........

:iamwithst

Another vote for Glow Plugs!!

Glow plugs suck a lot of juice, and the PCM slowly raises alternator output to keep from loading it too much too quickly.

your PCM will slowy increase the voltage (load) as to reduce the amount of power stolen from the crankshaft while initially starting up.

Hello, I've only had my diesel truck a few weeks. This is the very question I had. Alt gauge slow to show charge, about a minute, then the needle moves, and meter shows 14.4 volts to the batteries. My mobile shop man said the same thing, glow plugs. I need to pay attention to see if this does the same with a hot engine start. Was about to buy a new alt, glad I didn't.

A little searching on a topic, and the answer was here, what a great place!!!

Alan

there are two circut that the glow plug relay operateres. the 8 individual glowplugs and the 1000w heater in the intake, it sit in the y-pipe between the manifolds. as most people know the glow plugs are used for intitial starting. the 1kw heater is used to warm the air until the cylinder are warm enough to maintane compustion effecience.

mine aint got no y-pipe heater.i need to see a pic of this.the only intake heater i know about is on the lbz.oops,nevermind i see he has the lbz.

Same thing noticed here...
In my case I also started noticing a slow crank, so, after confirming with a few other Duramax drivers about the 30-45 seconds delay before the voltage pops up to 14.4v, I pulled my batteries to have a load test done.

Both failed.. They're a bit over three years old..... so I guess it's time for a couple new ones. But it was a relief to find out the delay in apparent charging wasn't the alternator.

there are two circut that the glow plug relay operateres. the 8 individual glowplugs and the 1000w heater in the intake, it sit in the y-pipe between the manifolds. as most people know the glow plugs are used for intitial starting. the 1kw heater is used to warm the air until the cylinder are warm enough to maintane compustion effecience.Yes, the 06+ trucks have a grid heater, but it isn't in any y-pipe. It is in the intake track right before the intake manifold. Here's a pic of it and where it is installed.

29383

i could be wrong about the LBZ
i do know the LB7 do part number is 97251974 (52$) i have seen it on my truck and in the schematics in the dealer's pc when i was looking fro the part

FWIW
glow plug #97226202 (15$ea)
glow plug/heater controler #97251974 (150$)

the y-pipe is the intake spliting off to each bank. the heater on the LB7 is mounter just upstream of the split it is under the turbo inlet to the compressor and just forward of it.

Yes, the 06+ trucks have a grid heater, but it isn't in any y-pipe. It is in the intake track right before the intake manifold. Here's a pic of it and where it is installed.

29383

Dang thats a nice clean interior - :mad:

there are two circut that the glow plug relay operateres. the 8 individual glowplugs and the 1000w heater in the intake, it sit in the y-pipe between the manifolds. as most people know the glow plugs are used for intitial starting. the 1kw heater is used to warm the air until the cylinder are warm enough to maintane compustion effecience.
:exactly:

Dang thats a nice clean interior - :mad:
Believe me, that is not the engine in my truck. My truck's engine is way dirtier than that.