Ok, interesting thing with my cav. When I am coasting, and only coasting, in D through about 33-28 mph, the volts drop to 11-12 fast, but spring right back to 14+. This causes all my lights to dim, and sometimes my stereo to skip. And twice over the last 8 months or so it has made it stall out on me. BUT this all goes away if I go from D down to 3rd. Volts stay at a solid 14.5-7 during deceleration/coasting (not engine braking, engine is below 1krpms). Now my old alternator died on me last week, and swapped in a new one no prob, and the volts dropping still occures, just not as bad. They only drop to about 12.5-13. Not low enough to stall the engine. The only thing I didn't do during the alt. swap was disconnect the battery. With the new alt, should I have disconn, the bat? Might that fix the volt drop? I know my old alt was going down hill fast with the subs overpowering it pretty quickly.
So theres my situation. And besides disconnecting my battery for 30 minutes, any other ideas I can try to cure the volts droping? Thx guys!
Did you remove the battery when the alternator failed and recharge it with a charger on the bench?
I am guessing that your battery was run down before the alternator change and, especially with an amp running as well, the alternator is not able to charge the battery AND supply all the normal loads as well as running the amp system.
I would fully recharge the battery and then try it again and post the results.
Hope this helps
Alont
Will do today. When I shut my car off for the last time before I swapped the new alt. I still had about 12 volts left, so the bat. was still strong. Once I saw the volts drop straight down to 12.5ish, I shut my lights off, dimmed the gauges, killed the stereo, even flipped down the face of my deck so even that wasn't pulling juice.
Just thinking about this, if the battery charges up OK.
I would next disconnect the Negative battery cable at both ends and ensure both connecting ends AND the chassis ground connection point(s) are shiny clean.
You may have a high resistance in the negative cable run, that would fit in with your symptoms
Alont
hmmmm never thought of that, when I get my car back from the shop, I'll check that out.
