3rd Gen Prelude with possible alternator problem

[Cameron Rodgers]

Hey guys, new to the forum here but long time fan of the show. Finally decided to pull the plug on an account on here because I need an opinion I can trust. I recently replaced the alternator on my 1988 Honda Prelude Si and to make a long story short I got a reman which ended up lasting me less than a week before I was going down the road and smelled something burning. My little volt gauge I put in started to tell me I was at 11 volts and dropping so I made the speedy nerve racking trip home to remove the alternator and bring it back to be checked and replaced. Sure enough it was putting out 8 volts which just isn’t even close to enough juice.

Well I get home and put the new *cough* I mean reman alternator in and at idle under no load I get around 14.35v which is all good. So I made a quick trip down the road and as I am driving I put a little load on with the headlights and fog lights as well as my stereo and that’s when I noticed a weird reaction from my volt gauge. As I am driving I noticed that the voltage starts to move around a bit from 13.5-14v which isn’t too strange to me but every now and again it would make a sudden drop to right around battery voltage and stay there for a few seconds and then jump back up. I checked the belt tension and all is correct, no slipping or weird smells. So I contact a buddy who used to work on these things and he mentions Honda’s dual mode charging system and says that it’s not uncommon for this when it comes to Honda and that unless my battery light comes on or I notice the volt meter drop for a significant amount of time, especially under battery voltage, that I shouldn’t worry about it.

Now for my mistrust because of the problems I have been having I really need a second opinion on this to put my mind at ease. I had the current alternator tested multiple times before I even left the store and passed with flying colors, so I just want to know if this is normal behavior and I am just looking for problems or if my concern is warranted.

Topic

[EricTheCarGuy]

It does sound normal, but anytime you alter a system, you are the primary suspect. Meaning make sure your voltmeter is hooked up correctly. If it is, and you don’t have a charging light on, you’re probably fine. More info here.

http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems

[William Richardson]

Do you have a sub/amp setup installed? If so, this would cause the voltage fluctuations as well and I would install a capacitor to relieve the stress on the electrical system. Audio amplifiers are alternator killers.

[Cameron Rodgers]

Thank you for the response, I should have stated that the volt meter I put in is not hard wired. It is simply a car charger type device that you install in an accessory or cigarette lighter port. When I first noticed this I suspected that the meter was wrong so I immediately pulled it and hooked up my multimeter and was able to recreate the fluctuations.

I do have a sub and amp hooked up in the car, but I installed it myself properly and had the foresight to wire in a capacitor as well knowing the alternator in this car is not high output. And with only 300 watts RMS the capacitor might be overkill but I prefer to take it easy on my electrical system. I only need to fill in the bass not turn my car into a rattle box. But as well I disconnected the system and was able to get the same result with my other stock accessories. As Eric said if I don’t have charging light on it’s probably fine and I am just worrying a bit too much. It just sucks to be stranded on the side of the road as i’m sure we all know haha. The first time when the OE alternator went, the charging light came on and I made it within 300 feet of my driveway with everything including the headlights turned off.

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