Terbronco7 Posted July 9, 2018 Share Posted July 9, 2018 Just finished restoring my engine, replaced Alternator ''old one clashed'' Started it up now my lights pulsate, dome light is bright then dim same with headlights! Checked all connections ground etc and all is good, any suggestions? Could I have bought a faulty Alternator? Thanks in advance for everyone help! Quote Link to comment Share on other sites More sharing options...
Rob Peters Posted July 9, 2018 Share Posted July 9, 2018 My 70 was doing this when I bought it.... i thought back to when I owned my original Monte and remembered it doing the same thing after I had owned it a few years. On my original Monte I remembered the fix. Not sure about a 71 and 72 must the 70 had a smaller wire coming off of the negative battery cable. This smaller wire attaches to the passenger fender with a screw. On my original one that wire had come loose (in reality, i had failed to tighten it after i had removed it to clean some things up. Once i tightened it up the flickering went away. On my current 70 Monte that wire was missing completely when I bought the car so until I could get a new cable with that wire attached I made one up and secured it to the negative terminal and the fender and that also fixed my flickering lights. Here is a link to one: 70+monte+carlo+sb+negative+battery+cable&oq=70+monte+carlo+sb+negative+battery+cable&aqs=chrome..69i57j33.27295j0j8&client=tablet-android-samsung&sourceid=chrome-mobile&ie=UTF-8#imgrc=XUScbU9tVkDZBM: Quote Link to comment Share on other sites More sharing options...
Terbronco7 Posted July 9, 2018 Author Share Posted July 9, 2018 Yeah checked that wire going from negative to fender, never removed it to be exact, so its good, one thing that may be the issue is I repainted the Brackets, engine block etc, I did not however scrape away new paint at contact points, gonna try that tomorrow see if that helps. Thanks Quote Link to comment Share on other sites More sharing options...
Mike Brichta Posted July 9, 2018 Share Posted July 9, 2018 Do you still have a voltage regulator on the car? That is what determines how much current the alternator needs to put out. I cycles back and forth with the current based on the load. If you still are using a voltage regulator, I would strongly suggest upgrading to a high output (105amp) 1 wire alternator and eliminate the voltage regulator. All of your lights will be super bright and your battery will thank you. I have done the conversion an all of my cars. Good luck!!Mike Quote Link to comment Share on other sites More sharing options...
Terbronco7 Posted July 9, 2018 Author Share Posted July 9, 2018 I believe it does still have the voltage regulator, I scraped all paint off on contact points and still no change, did not do this with old alternator, unfortunately it is gone due to core exchange so I am going to swap for another one and see if that helps. Fingers crossed Quote Link to comment Share on other sites More sharing options...
Terbronco7 Posted July 10, 2018 Author Share Posted July 10, 2018 Ok so new Alternator, still same issue! I don't get it, with old one it was fine! Guess I can try the regulator, after that I'm at a loss Quote Link to comment Share on other sites More sharing options...
Rock Posted July 15, 2018 Share Posted July 15, 2018 Do they pulsate when the car isn’t running? My guess is the regulator might be going bad. One thing to test is to see what the voltage level is coming off the alternator before it gets regulated and see what you get after it gets regulated. You should get a solid 12vdc after regulation. If it is varying say 12 - 14vdc after the regulator would be bad. You should get at least 14vdc off the alternator at idle and it will go higher as the engine speeds up. Personally I would bypass the regulator and add an internally regulated Alternator. Quote Link to comment Share on other sites More sharing options...
Terbronco7 Posted July 16, 2018 Author Share Posted July 16, 2018 Do they pulsate when the car isn’t running? My guess is the regulator might be going bad. One thing to test is to see what the voltage level is coming off the alternator before it gets regulated and see what you get after it gets regulated. You should get a solid 12vdc after regulation. If it is varying say 12 - 14vdc after the regulator would be bad. You should get at least 14vdc off the alternator at idle and it will go higher as the engine speeds up. Personally I would bypass the regulator and add an internally regulated Alternator. only when its running, when I press the throttle it gets brighter Quote Link to comment Share on other sites More sharing options...
Blake350 Posted November 4, 2018 Share Posted November 4, 2018 I have the same issue- visible pulsation of brightness on all lites when running-..and still have the old black box delco regulator up on left front..short of changing to internal alt/reg,-the original alt was just rebuilt-maybe switch to an electronic version of the external regulator?? i thought I remembered some of the members doing this? Brian Quote Link to comment Share on other sites More sharing options...
Leghome Posted November 5, 2018 Share Posted November 5, 2018 My 72 had an electronic regulator and it went bad so now have a single wire 100 amp unit. Quote Link to comment Share on other sites More sharing options...
Blackhawk Posted November 6, 2018 Share Posted November 6, 2018 On 11/4/2018 at 4:55 PM, Blake350 said: I have the same issue- visible pulsation of brightness on all lites when running-..and still have the old black box delco regulator up on left front..short of changing to internal alt/reg,-the original alt was just rebuilt-maybe switch to an electronic version of the external regulator?? i thought I remembered some of the members doing this? Brian Wells VR715 is the solid state version of the stock regulator. It does look a bit different, but if it bothers you the stock cover can be put onto it. You can do the full field test to see if it's the regulator. Also, check your connections, if everything is stock it could have some corrosion after all this time. Quote Link to comment Share on other sites More sharing options...
imr Posted February 22, 2019 Share Posted February 22, 2019 I would go over your grounds again. not sure on your vehicle did you have a ground strap that went to your firewall. did you clean paint off mating surface. also check you voltage at the alternator and the battery with an analog meter if you have one. see if it pulses also. Quote Link to comment Share on other sites More sharing options...
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