Delayed charging
#1
Nordschleife Master
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'02 996. Alternator does not start charging until ~4 seconds after the engine fired up. Warm or cold, SAI pump running or not. Makes no difference.
Once it starts charging, it stays at good level 13.5~14.1v whenever the engine is running. Drive belt is not slipping. No warning lights or CEL. No codes from Durametric.
I noticed this behavior on the voltmeter in the dash and also verified the same from the cigarette lighter.
I know that some Bosch alternators have a soft-start feature where charging will be delayed up to 14s (to reduce alternator load impact immediately after start up) but AFAIK, our stock alternators don't have such fancy feature. I wonder if the regulator was replaced with one having such feature. Other than that I can't explain it. Anyone experienced this?
Once it starts charging, it stays at good level 13.5~14.1v whenever the engine is running. Drive belt is not slipping. No warning lights or CEL. No codes from Durametric.
I noticed this behavior on the voltmeter in the dash and also verified the same from the cigarette lighter.
I know that some Bosch alternators have a soft-start feature where charging will be delayed up to 14s (to reduce alternator load impact immediately after start up) but AFAIK, our stock alternators don't have such fancy feature. I wonder if the regulator was replaced with one having such feature. Other than that I can't explain it. Anyone experienced this?
#3
Nordschleife Master
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Yup, that's what I'm thinking but I'm too lazy to remove the alternator to find out.
Very disconcerting when I see the voltmeter reading staying at 12v for 4s when the engine is running. Kinda like seeing the oil pressure at 0 bar when the engine is running
Very disconcerting when I see the voltmeter reading staying at 12v for 4s when the engine is running. Kinda like seeing the oil pressure at 0 bar when the engine is running
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#5
Nordschleife Master
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I also did a leak test (like you) before installing the engine too
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#8
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check/change the battery. If it's not holding a good charge or has damaged cells that could be the issue. If the act of starting is drawing it down too low the alternator will be busting its *** to bring the charge back up on the battery. While the battery is sucking up all the power, the voltage will drop and normalize at 12v (the battery).
#9
Drifting
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First start video...Oh the one where you couldn't get the engine to stay running?![Big Grin](https://rennlist.com/forums/images/smilies/biggrin.gif)
Yeah went back and watched the gauge...interesting. If it is consistent your guess may be right...soft start. I'm not familiar with that but it does make sense.
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Yeah went back and watched the gauge...interesting. If it is consistent your guess may be right...soft start. I'm not familiar with that but it does make sense.
#10
Nordschleife Master
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Good thoughts but of course I've also tested my battery and it seems healthy. I can do one check though. I can connect my booster pac and start the car and see if that makes a difference.
check/change the battery. If it's not holding a good charge or has damaged cells that could be the issue. If the act of starting is drawing it down too low the alternator will be busting its *** to bring the charge back up on the battery. While the battery is sucking up all the power, the voltage will drop and normalize at 12v (the battery).
#11
Nordschleife Master
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Yeah I'll just have to wait till next time I remove the alternator. Then I can check the regulator.
#12
Nordschleife Master
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That was a good thought though.
#14
Nordschleife Master
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Switched to DT40 at around 500 miles and it's at about 700 miles now. Plan to drop the oil pan at 2,500 miles, do some inspection and send the oil out for UOA.
DD'ing it now...hard to keep my foot off the gas pedal with the new found torque
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#15
Captain Obvious
Super User
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The exciter circuit in the alternator might be going or the reference wire, in or outside of the alternator, is loose/broken. Pull the alternator, have it bench tested and then go from there.