Hey guys, my alternator light is staying on. The story is I put my 289 in last week, got her running this week and the alt. light is staying on still. I've got a new battery (which reads 14volts on my gauge inside the car), new alternator, new voltage regulator, and a new starter solenoid. Any Ideas? Thanks in advance!
What voltage regulator did you use? One of the old style looking mechanical ones or a modern solid state one? I have had trouble with the modern mechanical ones - ALT lamp staying on even though the voltage is fine.
High rpm is needed to excite the regulator. I went through about 3 electronic regulator to find one to charge without reving the engine up to 3,000+.
When buying a new voltage regulator ALWAYS have it bench tested before leaving the store. For some stupid reason they do not pre-set them correctly in about 3/10 of them. The last time I was looking for them I made the guy go through the entire stock at Autozone before finding 1 that passed their bench tester.
Bingo ............ ............. 95% sure this is your problem. If it is one of the look-a-like Autolite or Motorcraft ones, and you want that vintage look, you can remove the cover and attach it to a modern solid state unit. Some solid state units have the 2 rivets or screws that hold the cover on and it is an easy swap. Some are bonded on and they do not come apart. Make sure to buy one that has the cover that is removable to do the swap. If you do not care about the "old school" look, just replace it with the modern solid state unit. Last year I did an article about this for Shorthorns. I will see if I can find the pictures and "how to" for a tech article here at the mmb. If you have an old VR laying around or could borrow one, try swapping it out and see if the light goes away.
If you or anyone else is interested, I re-published the voltage regulator article. Here it is http://www.maverick.to/mmb/showthread.php?t=98938
So, I just realized, on the pictures from the article, I think I may have a modern regulator, its the same one as the grey regulator in the picture that says "short circuit protected"....
Hmmm ......... OK....... so many questions that are easy in a FTF, but requires lots of typing back and forth when using the interweb-thingy. Lets back up, as it sounds like you have a solid state unit (which can be bad out of the box too but that is rarer compared to the mechanical ones). See, the VR has a relay circuit inside of it that controls the ALT lamp. In these old cars it is easy to change something in the wiring of the car or ground that causes the lamp to glow. Do you have an actual voltage meter to test voltage at the battery (not just the gauge in the car)? ----TEST: Car off, battery will read 12.5-12.8 volts - engine on 1500 rpm, should read around 13.8 volts plus or minus .4 volts. Make sure when doing this test - everything else is turned off (fan, radio, all lights). If it reads OK - now take the same reading at 1500 rpm with all lights, fan, radio turned on. Did the added volt gauge in the car work OK before with the alt light? Or is this gauge something you recently added with the engine change? If all the test readings from above normal, and this volt gauge was just added, disconnect it and see if the ALT light remains. Do you have an old VR you can toss in to see if this changes anything? I'll keep trying to help as long as you want ............
