Hi there guys. I've been having a problem for about 2 months now with my car's voltage. I replaced the alternator and battery and they were testedso they are working properly. I also checked the main ground wire and starter wire and everything seem to be ok. Voltage is good until I turn the A/C and/or the headlights and it drops down to 11.XX volts when the car is at at stoplight or heavy traffic. A few times already the car won't start after turning it off. I jump start it and it will start for a week or two until the same thing happens. Please help me out here.

 

have you measured the output voltage at the battery at idle?
Should be 14.5 with a new alternator ( or really close)
Those gauges inside the car are very inaccurate

If all the components have been replaced it must be in the wiring, most likely either
A. Believe it or not they wired the alternator *kick in* through the fan circuit, if that fuse is blown it will only charge 11 volts give or take and drain down the battery.
Or B. your fusible link is getting bad and intermittantly when load is applied it might open the circuit, leaving the alternator charging NILL, or no voltage,
Fusible links are very cheap and easy to replace i would suggest getting a bigger gauge of wiring, maybe 12 gauge or close to it, the stock is a 14 gauge. Some people have even just rewired it with a inline fuse to fix the problem.

good luck!

 

I had a similar problem and it was the crappy autozone alternator that I used to replace my original delco. I replaced it with a powermaster from summit and have had no problems since. I would test your alternators voltage and amp output at idle. I have heard of guys going through 3 or 4 alternators from the discount auto stores until they got a good one.

 

Cheap/weak rebuilt alternators will sometimes give low voltage, particularly at low RPMs.

When you kick on the A/C and the voltage drops does it just get low at idle or does it stay low even with the motor revved up? That would indicate different kinds of problems.

I can almost smell a bad alt. rebuild from here.

 

come to think of it when i went through my "charging" delima i went through 2 alts before the 3rd one finally worked out. Allied auto parts = good qual
Autozone= * BEEP* bad, 2 in fact

 

I already tried 2 alternators. I also tested the car with my friend's Formula alternator, which was working properly, and the problem still exists. I replced the fusible link so now I'll check the fan circuit and wires.

 

HI, how did you go?

I know this might seem silly, but I'm jsut going to say what I know has fixed these sort of problems before.

Do you have a Good heavy earth strap from the NEG of the Battery to the Frame? AND a GOOD thick one from the NEG of the Battery to the Enigne Block?

The other thing you could do if your still wanted to make it 100% is remove the fuse holder under the dash and spray a electronic cleaner in from behind and then the front. Also check all the Fuse links, I know some of them had them comming off the starter motor.

Let me know how you go.
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[QUOTE=Francis;3110283]
Do you have a Good heavy earth strap from the NEG of the Battery to the Frame? AND a GOOD thick one from the NEG of the Battery to the Enigne Block?
QUOTE]

I cant tell you how important this is. I know some guy's will say oh but mine works, but honestly, I've seen all sorts of issues with poor earthing. What might work with out one earth wire to the block or just using an old thin wire to the frame, after time issues will come.

Clean all the earth connections, and make sure you have two heavy gauge cables 1 to the engine and 1 to the frame.

 

I checked the ground wire from the battery to the block and installed a new one from the block to the chassis. My fuse box looks kind of abused so I'll check that too. I'll let you guys know as soon as I find out. Keep the ideas coming please.