So today I was stoplight racing a chevy 2500 (BTW I won), but what I noticed was that at about 5k-5,500 RPM's the battery light started to flash. So I tried to replicate theproblem, and everytime I punch it, and get the RPM"s up that high the light will come on. I also noticed that the headlamps dim also when the RPM's get this high. Iam thinking that Ihave either a slipping belt, or a bad altinator. Anyone else ever have this problem? Any other thoughts. I am going tohook my scanner up to it later tonight to see if anything is noticable via that (I can monitor some live data with my scanner)

Thanks in advance

Charles

 

I had this same type of problem between 700-1500 rpm over that the light went off, it was the alternator,and check the single wire connector on the alternator it works lose,if it dont fit tight change it.Hope you figure it out.

 

That's a good thought -- another possibility is a slip-ring brush problem and they're not making proper contact at higher RPM's for some reason. You can take the alternator off, remove the regulator and inspect that for problems.

Yet one more problem is a separated rotor bus connection. There is a small bussbar that extends from the slip-rings to where the rotor wire connects and that solder connection can crack. When that occurs centrifugal force can actually pull the connection apart. That happened to my current alternator and I had to take it apart and resolder the connection.

 

Hmm, I think I may have found 2 additional possibilities.
Mine has been doing it also. Very odd
I'll look into that.
John how hard is it getting all that apart and soldering it?

 

Mr. Griggs, I can take a look at that stuff that you mentioned. Thanks for your response. I am guessing a new Alt. is in my future... I am not much of one to solder. But will check it out wen I take it apart.

 

It's a big connection, as a matter of fact. Takes a good sized iron. I used a large butane powered "Blue Point" one I got off the Snap-On truck.

I was able to get at it through the hole left when you remove the regulator and I didn't have to disassemble the whole unit.

 

For those of you that have replaced your alt. did you get the 95amp or the 130amp? I will get the 130, just wondering what everyone else got.

 

It looks like I have a new one in my future also, I'm going 130

 

bigger is better, why go with the lil baby 130 when u can get the jumbo 180amp? then u can get a tremor like pkg....

 

I didn't see the 180 as an option....

 

My Caddy is doing the same thing. I figured it was the voltage regulator doing something stupid. Guess I know what it really is now. Cheap pos Advance Auto alternator. Damn thing's only been in the car like 6 months!

 

your truck is so powerful that random lights turn on under wot!

 

hehe I wish....

 

my light has been comming on and off at different rpms for about the last week. funny thing is I can drive it for 30 mins and the light never comes on, or I can drive across the street and it flashes 5 times.

 

My battery light also comes on around 5,000 rpms. I've datalogged it and my amps (volts?) drop into the low 12's at that point. In my case it's causing my fuel pump to lose power and my fuel pressure drops causing the truck to lose power. The fuel pressure drop is actually what I noticed and what sent me searching for the problem. It shouldn't be a slipping belt as I've tried to put on many different sizes and I have the smallest I could find. Now I'm looking for an alternator. I found a 200 amp one but it is only listed as for up to a 2001. Does anyone know if there is any difference between 2001 and 2003?

 

yes there is a difference.. what I am not sure, but I know the stock alt are 2 different part numbers. So i am sure the aftermarket ones are different.