After installing three previous alternators this is what happened with two new Delco units. This was posted in the V8 Buick chat. "Okay, we tried both new Delco voltage regulators Regulator #1 at idle the lights were on and surging, charging was at 17 volts and generator light was on. We tried to lesson the spring pressure and the voltage swung from 13 to 17 volts constantly. Generator light stayed on. Regulator #2 With raised rpms, voltage was 13.9 to 14.1 the light was off. At idle voltage went to 17 generator light came on." My mechanic and I are still trying to figure this out, the issues were similar with the three previous non Delco regulators. Any input is appreciated. The car is a 68 GS400 with the stock 400 engine.
After a handfull of alternators and regulators ,all having similar results, I doubt if they are the problem. Probably in the wiring. Bad grounds are the most likley cause. Another possibility would be low voltage at the #3 terminal of the regulator. Try adding a ground from the alternator negative post to the regulator. If regulator #3voltage is lower than battery voltage, try a temporary jumper from the battery pos to the #3 terminal. Let us know if you see any changes.
My original voltage regulator failed, and I tried a couple of replacements that were out of spec one way or the other. I tried the cheap chinese unit (that has a circuit board inside) and it works perfectly. I swapped my Delco cover on and haven’t had an issue since. Patrick
Not necessarily a comedy of errors but because the recon alternator was bad we were chasing gremlins that didn't exist. We went and bought another solid state regulator and with the good alternator, everything was good. Whew.
