1993 Toyota Supra Re: Alternator

Tiny
SUPMETH
  • MEMBER
  • 1993 TOYOTA SUPRA
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
Hi,

I suspect my alternator is having issues and need clarification. While my engine is running and I disconnect the battery my engine shuts down. Although the symptom is no longer present, from time to time my car used to stop when idle.

Also, would an issue with my alternator have an impact on other electrical components. My first car stereo stopped functioning one day. The led still lights but it doesn't play or display anything on the screen. I purchased and installed a new stereo and the same problems occurred. Would this problem be cause by under-voltage or over-voltage due to irregular current outputted by the alternator? Is there anything else that could be a likely culprit and what test can I run to rectify this problem?
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Saturday, November 1st, 2008 AT 7:03 AM

3 Replies

Tiny
MMPRINCE4000
  • EXPERT
First, NEVER disconnect the battery while the engine is running, it can damage the rectifier and diodes.

Take the car to any autoparts store and get the charging system tested for free.

The stereo has two power connections, one is hot all the time and the other is a switched ignition source, check both with a multimeter for 12V and make sure you have a solid ground.

Check the fuses to the stereo and any fuseable links.

But, again get the charging system tested first as a starting point.
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Saturday, November 1st, 2008 AT 7:37 AM
Tiny
SUPMETH
  • MEMBER
Hi again,

I haven't taken the car for testing yet, probably do over the weekends.

The unusual thing though, my stereo system is now back on but my panel lights are out.

So it appears the electrical components are turning off intermittently.
- Engine shutdown awhile ago when idle
- Stereo shutdown around a week ago
- Now the panel are off

I did a bit of testing with the multimeter:
Engine off = 12.75V
Engine Idle = 13.8-14.2 V
RPM@2500+ = 13.8 V

Any idea what would be causing this problem?
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Monday, November 10th, 2008 AT 6:04 AM
Tiny
MMPRINCE4000
  • EXPERT
You need to test the alt. Loaded and unloaded.

Loaded would mean lights, AC etc. ON.

Some will charge fine unloaded but fail loaded.

Get the alt. Tested, then go through the fuses and fuseable links for any bad ones.

This is probably directly related to running the car with the battery disconnected.
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Sunday, November 16th, 2008 AT 8:04 AM

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