I've had this swap running for over a year. about 5 months ago I put a 525CCA (pretty large footprint) batt brand new in the car and didn't think anything of it since then.
Recently I've been having starter cranking problems. I attributed this to aging starter.
Then I accidently left my headlights on, completely killing the new battery.
Well I got it jumped, and drive it around 30 minutes to re-charge.
However there was very little charge in the batt after 30 minutes. I think the alternator is barely charging the battery.
I disconnect my batt. cable and the engine dies after a moment, also making me realize there is an alternator problem.
I see fluctuations in voltage sometimes with a tester. The voltage usually rests around 12.6 to 12.8 on a tester, so I know the alternator is working still. At least some. Also I see CONTROL MODULE VOLTAGE in the Hptuners scanner as 13.5V to 13.2V Most of the time
hptunerlog9-18-17.jpg
And I've never heard of an alternator "sort of dying"? It makes me think the problem is TRULY with the L-terminal wire, or the wire that turns "on" the alternator. I think it might just be not fully turning on. Or that part could be going bad. It is an original 1998 alternator from an LS1.
So here is how mine is wired. I made this schematic a while back for the swap
alternatorfinal.jpg
I put the brown wire into pin B. My next idea before replacing the alternator is to remove the computer control and try a typical 500ohm lightbulb lamp (is that right? iirc) to 12v and see if it will put out 13.5 or so on my meter full time instead of the 12.6 to 12.8 it does now. Is there alternatively anything I can do or my have accidentally done in Hptuners to affect this issue...
If anybody has any other comment suggestion (besides change the 25 year old alternator lol) I would love to hear it. otherwise this is simply an diagnostic events thread for records.
Update: 10-6-2019
sometime last month I finally realized that I have removed and never replaced the engine -> chassis ground cable.
Somehow the engine has been starting, charging, and running.... fine... I guess. All this time (maybe 1.5 years?!) without the cable attached.
Then I swapped the cam. And I think the extra spring pressure, just pushed it over the edge. The engine would no longer turn over anymore, even with a very strong battery.
The day after that happened I realized the cable was missing and... its been @*&@#*&$ing fantastic ever since, the motor cranks like it was hit by a bolt of lightning now.