Charging issues

Tiny
ARMY MECHANIC
  • MEMBER
  • 2002 FORD FOCUS
  • 2.0L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 207,883 MILES
Replaced the alternator with a brand-new one car only charges above approximately 2000 rpm's the new alternator was checked and works fine but it only charges above 2000 rpm's. Cannot figure out what is going wrong with it.
Wednesday, November 29th, 2017 AT 8:01 PM

10 Replies

Tiny
MHPAUTOS
  • MECHANIC
  • 31,938 POSTS
Is the charge indicator light coming on at all? Also, there are three VIN numbers I need to check, so can you advise the full car VIN please?
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Wednesday, November 29th, 2017 AT 10:03 PM
Tiny
ARMY MECHANIC
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The charge indicator light comes on about one minute after starting up and stays on unless I rev the car above 2000 rpm's. The car listed above is the sE model with the Zetec DOHC. According to the belt routing diagram this is the VIN n engine. If that is not correct then all of the parts on it come from the VIN 3 engine.
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Thursday, November 30th, 2017 AT 6:51 AM
Tiny
KHLOW2008
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Check the crank pulley damper. It could be bad and freewheeling thus reducing the alternator turning speed.
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Friday, December 1st, 2017 AT 5:48 PM
Tiny
MHPAUTOS
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Not a lot can go wrong here, apart from a problem with the alternator, the PCM and cluster light are all that is involved. I would look at what KHLOW has suggested and also ensure all earths are okay. If that is all good, I would consider looking into a problem with the PCM.
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Friday, December 1st, 2017 AT 8:21 PM
Tiny
ARMY MECHANIC
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Going to try replacing the positive cable from the alternator to the battery then going through all electric connectors and tightening them up first. Do not think the crank should be an issue since it has had a complete engine rebuild in the last two years and crankshaft and pistons were completely replaced with performance parts.
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Friday, December 1st, 2017 AT 10:36 PM
Tiny
MHPAUTOS
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My feeling is a problem with the circuit, checking all the cables and terminals is a good place to start.
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+1
Friday, December 1st, 2017 AT 10:55 PM
Tiny
ARMY MECHANIC
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Thanks for at least trying to help me out mhpautos. I know a lot of my issues on my car does stem from the crankshaft and pistons, but this is one time it cannot be. My timing has to be two teeth a head of factory or else it does not fire correctly, but I know from experience that it will not cause this issue.
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Saturday, December 2nd, 2017 AT 12:39 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,787 POSTS
Hello,

To me it sounds like you have a bad alternator even though it tests good. This happens when a diode starts to leak which dissipates at higher RPM. Please use AC Delco or Motorcraft when replacing the alternator.

This guide can confirm the failure under AC volt checking

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Please let us know what you find. We are interested to see what it is.

Cheers, Ken
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Monday, December 4th, 2017 AT 1:38 PM
Tiny
ARMY MECHANIC
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Positive cable fixed it
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Monday, December 4th, 2017 AT 7:51 PM
Tiny
MHPAUTOS
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Well done, thanks for using 2carpros.
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Tuesday, December 5th, 2017 AT 3:43 AM

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