1993 Brooklands Charging at idle
Looking for some advice, ideas to bounce off of. I have checked the idle of my 1993 Brooklands to make sure it isn't idling too low and it doesn't seem to be (600 RPM at idle in gear). I have checked the Bosch ISV and it seems to be performing correctly. My continuing issue is at night with headlights on and AC fan running when I come to a stop from highway i can watch the lights dim, voltage gauge drop to below 12 volts and then the engine dies (most likely due to low voltage at the ECM). I can start the car right back up no issue what so ever every time. I have a battery that is consistently at full charge as I keep a very very small trickle charger on it at all times. The alternator has been rebuilt twice (first time it needed it, second time because I told them I didn't think they fixed the issue the first time). Shop tells me it charges perfect, and at highway speeds it is. If at idle I can catch it quick enough it only takes the tiniest blip of the throttle to make the voltage gauge go up to 13.5 volts or so and car idles fine. So, my question is, do I need a smaller alternator pulley, or does it sound like I'm having a huge voltage drop in the wiring of the vehicle somewhere? I would assume the battery would keep enough voltage to the ECM at idle with loads, but it is not seeming that way. Any help or advice would be appreciated, its becoming unsafe to drive at night. The alternator shop told me that they have in some cases found a smaller alternator pulley for the older Rolls/Bentley or older Cadillacs that use this design engine and it solves the problem.
Last edited by kylel2838; 08-08-2019 at 12:12 PM.