Voltage drops at WOT

[Bedore]

Well, here I am with another annoying issue. I noticed that when under WOT, my voltage drops from 13.5-14 to around 11 or 11.5, and the dash lights will dim/flicker, as will my headlights.

Alternator is putting out 14.0 volts solid, the battery is holding a charge. Alternator looks to be fairly new as well. What else could cause this?

 

[greenhornet]

get your alternator tested as it could have a bad diode or one of the fields is breaking down.

 

[91RS]

Don't hold me 100% to this, but I believe the alternator and A/C compressor are turned off by the PCM on WOT.

 

[Bedore]

Don't hold me 100% to this, but I believe the alternator and A/C compressor are turned off by the PCM on WOT.

Interesting....can anyone else chime in on this? If so that would certainly explain the drop in voltage.

 

[thehoe92]

I do not agree with that because I have had a voltage meter on my battery since I put my system in and I have had countless times where it was WOT and if anything it should make your voltage go up .1-.2v

it almost sounds like your belt could be slipping on WOT causing the alternator not to spin which would make your voltage drop

thats the only thing I can think of

 

[Bedore]

I do not agree with that because I have had a voltage meter on my battery since I put my system in and I have had countless times where it was WOT and if anything it should make your voltage go up .1-.2v

it almost sounds like your belt could be slipping on WOT causing the alternator not to spin which would make your voltage drop

thats the only thing I can think of

Battery and alternator tested OK. While I cannot rule them out completely, I think you may be right; I am going to change out the belt to a decent one.

 

[2005yukonxl]

Don't hold me 100% to this, but I believe the alternator and A/C compressor are turned off by the PCM on WOT.

not alternators. only AC compressors at WOT.

 

[thehoe92]

gator belts are pretty solid belts lots of grip on them

 

[Bedore]

I replaced the serpentine belt today with a gates belt. The problem still exists. I think I may need to get my charging system checked out. I am thinking the alternator.

 

[greenhornet]

If the belt was slipping it would squeal like a pig.I have seen many alternators on motorcycles charge great at low to mid speeds but loose power at higher RPM's.