Engine/Transmission (1998.5 - 2002) New alternator behaving oddly

[Schlickenmeyer]

Howdy all,



I put in a new alternator yesterday, seems to be fine except for one small issue.

at start up the gauge reads battery voltage for 12 seconds, then it goes up to 14-15. The grid heater seems to draw her down a little more for a few seconds after she hits 14. Then all is perfect.



Thoughts? belt is tight, tensioner seems ok.



Thanks!

 

[bnbrown]

on both of mine when the grid heaters are engaged voltage drops to near/at the lower line for normal, then will bounce back up when grids turn off. Usually takes a few seconds after the grids turn off for it to go from a hair to the left of the center mark to the normal 14. 8 (once running of course)

 

[Schlickenmeyer]

This is not normal grid heater activity, used to go to 14 and there was a little pull down from the heater, now it just stays at 12 from on to start, and 12 seconds later, she jumps to normal. Same hot or cold.

PCM? Sulfated 1 year old batteries? bad heater?



Any guesses appreciated.

 

[Tractorat]

I have the same issue. Original batteries in my 02. Even if Ive been driving for a couple of hours and the grid heaters dont come on, the needle is on the south side of normal for several seconds before it comes up to 14v.



Im anxious to see if someone can point me in the right direction. Can it be as simple as batteries ?



TRat

 

[JFaughn]

Just an idea , I put a new [ Larry B's ] not rebuilt in my truck , and it took some time days , a week or so , my charge gauge kept on going higher [ form about just under 14 to a little over ] my thought is the brushes were breaking in .

 

[DPellegrin]

Schlickenmeyer- Get a good volt-ohm-meter (VOM) like a Fluke or Simpson and take your voltage reading directly from the battery posts. A fully charged battery is 12. 6 volts when you turn the key on the grid heaters draw the batteries down to about 11. 2-11. 3 volts. When the engine starts and the grid heaters are "on" voltage is 12. 3-12. 4 when heaters go off voltage is 14. 4-14. 5 at 3F. This voltage regulator is temperature compensating so voltage is a little higher the lower the temperature; however, I have never seen any higher than 14. 7 at -20F.



Regards,