1986 Prelude charging system

Tiny
JOSMIALO
  • MEMBER
  • 1986 HONDA PRELUDE
I have a 1986 honda prelude with the 1.8L engine in it. When you increase the rpm's above idle or turn on a perifial device such as the head lights the voltage drops to 11.5v. At no point will the voltage go above 12.5v I have put in a new alternator, a new belt, a new external voltage regulator. I also have new battery cables, a new battery and a new starter. What else can I check?
Thursday, May 4th, 2006 AT 1:50 PM

5 Replies

Tiny
LOSONE
  • MECHANIC
  • 1,616 POSTS
Replace the alternator, it will fix the problem. It has an internal voltage regulator that sometimes fails
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Thursday, May 4th, 2006 AT 3:03 PM
Tiny
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I did replace the alternator 3 times. Still the same problem.
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Saturday, May 6th, 2006 AT 11:07 AM
Tiny
LOSONE
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Where did you purchase the alternators? Discount stores are a poor choice because sometimes a core is cleaned and reboxed and sold as rebuilt. I have experienced 85% returns on alternators and starters. The only thing I buy from adiscount store I can pour out of a bottle. It's always the mechanics saying "pay me now or pay me later." I am a pro with a pros experience.

Also you need to check the grounds on the battery side. REMOVE all grounds that are attached to the engine, frame and engine to fire wall. Clean them GOOD so the metal is shiny on both surfaces. Sometimes a bad ground will cause an alternator overload in excess of it's rated output.
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Saturday, May 6th, 2006 AT 1:03 PM
Tiny
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Ok, so I took the alternator back to auto zone, where I got it. They tested it and said it was good. I then took it to 2 other places where it tested bad. My new one will be here in 3 days. I just replaced the external voltage regulator a few days ago. Could it have been the reason I burned out 4 alternators?
I also cleaned all my ground connections when I replaced the regulator.
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Saturday, May 6th, 2006 AT 1:44 PM
Tiny
LOSONE
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As a good rule of thumb, it is always necessary to replace the voltage regulator with the alternator.
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Saturday, May 6th, 2006 AT 3:14 PM

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