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post #1 of (permalink) Old 06-09-2009, 07:46 AM Thread Starter
Caver Dave
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Delco 3wire Alt. Troubleshooting

OK, maybe I spoke too soon earlier and didn't want to continue polluting PHX's thread...

Delco 3wire of approx. 55A of unknown origin. IIRC, "sense" circuit is wired to alt. output?)

As stated, no issues over the past 8 years. Continues to keep the batteries (I have 2 redtops that are swapped out every 4-5 months) charged and the juice flowing. However, since the TBI conversion, the ALDL data shows 2 things that are a bit confusing:

1) After starting and allowed to idle, WinALDL is only seeing 11.8VDC at the ECM. *IF* I rev it once, the voltage will jump to 13+VDC (charging) and remain until shutdown.
Is this a product of the way it's wired?
Normal, as in it may take an off idle rev to get the alt "excited" and begin charging?

2) During my data logging runs, there are occasional spikes to 20VDC. These spikes only show for 1 data entry (polled every 1.2 seconds) with no ramping, increase, or decrease in voltage before/after that entry. IOW, it shows say 13VDC for 20seconds, then 20VDC for 1 second, and followed by 13VDC for the next 20-30 seconds. As best I can tell (from the data), they are completely random spikes with no regard to RPM, engine load (MAP), etc. and only show about 20 such spikes out of 8000 records (1+hour run).
What does this indicate?
Faulty data? (hard to believe, since the rest is dead nuts on)
Junkyard alt (or internal component) on the way south?

Caver Dave
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