Alternator Voltage Climbing When WOT
11-05-2016, 08:11 PM
#1
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Alternator Voltage Climbing When WOT
Had some strange voltage issues at the track yesterday and doing some searching I can't find any answers so I need some help. I'm using a ms3x and have a NB alternator controlled by MS. Since it's in a NA I've accounted for the weird voltage drop to the ECU so the alternator is outputting the correct voltage even though my target is 13V. What happens is around 6000rpm in 3rd/4th gear the voltage starts climbing. The ECU is still commanding 13V so I'm not sure what's going on. I'm using Inj G as the output with a 330ohm pullup to 5V. Street driving I've never had a problem, it sits constantly at the correct voltage. Any ideas on what the problem might be?
Screenshot of datalog:
Alternator Settings:
Screenshot of datalog:
Alternator Settings:
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05-01-2017, 08:51 PM
#4
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Just in case anyone with the same issue stumbles onto this thread, I fixed the problem by using the high frequency output PT4 as the output instead of a mid-current output with a pull-up resistor. Had the exact same issue in a MSM using the VVT output with a 5V pullup which was also fixed by swapping to PT4. Since PT4 is a 0-5V output with no 5V pull-up resistor required the output polarity needs to be swapped from inverted to normal.
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