WOT causes voltage dip?
06-08-2011, 11:00 PM
#1
WOT causes voltage dip? I noticed earlier today that once the engine is reaching ~3500-4000 at WOT, my battery voltage (usually 13v on the gauge) drops a solid 1/4" to the left at WOT, then returns to normal when I return to normal throttle. That seems to be new behavior, any ideas what would cause that? Thanks!
06-09-2011, 01:34 AM
#2
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Haha.... this reminds me of a very odd problem I once had with my '98 Z years ago. Maybe this might help you....
Similar to yours, I would lose voltage under hard acceleration (so much so, that the "check gages" light would flicker). I could not duplicate the problem while free-revving the engine. Like yours, this was a problem that just randomly appeared one day, then became more regular, but only occured when the engine was fully warm. I went through all the usual checks (including gage cluster, verify gage with scan tool, check all related connections) and decided to just replace the alternator. To my disgust, the problem was unchanged.
I remember standing in the drive way, frustrated, looking at the alternator.....I noticed that there was an engine ground strap (the exposed woven copper kind) running right over the top of the alternator, resting on the alternator case. I had a helper load the engine a bit while in gear (brake torque), and saw that ground strap get dragged accross the vented section of the alternator case as the engine twisted under load (didn't happen with a free-rev). I moved the ground strap away from the alternator, and the problem has not returned in the ~6 years since.
Similar to yours, I would lose voltage under hard acceleration (so much so, that the "check gages" light would flicker). I could not duplicate the problem while free-revving the engine. Like yours, this was a problem that just randomly appeared one day, then became more regular, but only occured when the engine was fully warm. I went through all the usual checks (including gage cluster, verify gage with scan tool, check all related connections) and decided to just replace the alternator. To my disgust, the problem was unchanged.
I remember standing in the drive way, frustrated, looking at the alternator.....I noticed that there was an engine ground strap (the exposed woven copper kind) running right over the top of the alternator, resting on the alternator case. I had a helper load the engine a bit while in gear (brake torque), and saw that ground strap get dragged accross the vented section of the alternator case as the engine twisted under load (didn't happen with a free-rev). I moved the ground strap away from the alternator, and the problem has not returned in the ~6 years since.
