Voltage Gauge Issue
#1
Voltage Gauge Issue
For the last few years I have had a bit of an issue with my 2003 350Z and the voltage gauge reading low. It starts off fine and then starts to drop a bit. If the car is running at anything above idle it is fine. Reading around 14 or so. When you depress the brakes it falls quite a bit into the 12.5 range. It does the same thing when I use the lights as well. I have replace the battery and the alternator a few weeks ago but this has not helped the problem.... Any ideas on what it could be?
THANKS I need the help on this one...
THANKS I need the help on this one...
#2
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The first thing I would do is get a multimeter and look at the voltages across the battery to verify that the gauge is giving you accurate information. Verify that first before digging into the electrical system.
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Clarification:
When the car is not idling, rpm above 1500, you have no issues?
If you're cruising down the road, turn everything on: fans, lights, step on the brake, the voltage remains at 14?
Voltage only drops when idling?
When the car is not idling, rpm above 1500, you have no issues?
If you're cruising down the road, turn everything on: fans, lights, step on the brake, the voltage remains at 14?
Voltage only drops when idling?
#5
The car has no issues when the rpm is above 1000rpm with lights fan defrost or brakes on. Once the rpm drops the voltage drops.... I have no idea. other then when it is cold it runs at the proper voltage once the car starts to warm up and run for awhile it has issues....
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#9
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I did some reading and it is common for alternators to need to be at 1000rpms before being able to supply full voltage under full current load.
That being said, you may be fine. What caused you to replace the battery and alternator?
That being said, you may be fine. What caused you to replace the battery and alternator?
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You probably need to start cleaning connection points within the charging circuit. Not fun, but there is definitely resistance in the circuit somewhere and corrosion is your most likely source.
It is possible for a fusible link to fail halfway, leaving your circuit with a high resistance choke point.
It is possible for a fusible link to fail halfway, leaving your circuit with a high resistance choke point.
#14
Car has been working well. It still has a bit of a drop when I hit the brakes but not going below 12 volts or having issues with the charging light coming on. I think I will replace the cables and maybe the fuseable link. This is the second alternator and the issue still persists. But not as bad as originally so running out of ideas a bit.
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