Low Charging
 

Hey, I need help. I have a 1992 Mustang GT 5.0. It is heavly modified. I also have a aftermarket stero system with all the bells and whistles. I just recently purchased a 140amp alternator to charge my battery. When my car is running over 1000RPM, the battery amp gauge shows it is getting a good charge. When my car is a idle (600RPM), teh gauge drops! In addition, my stero will cut out if it is cranked up. I installed the alt. exactly the way the instructions said to and it came with a computer print out showing the test results before they sent it to me. I thought that it was my underdrive pulleys so I put the stock one back on and it still gives me the same problem. How do I get my alt. charging to it fullest when my pony is a idle?

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Cyberstang5.0
1992 Mustang GT 5.0

I had a similar problem with a different car.

Make sure you have a good ground for your amps.

Are you running multiple amps for your system?

Are they all grounded at the same spot?

If yes to both make sure it's a proper ground.

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1990 GT 5k Original miles!!
Ripper,Pullies,73 MM C&l Mass Air,9mm Wires,Piaa Headlights,MAC Cold Air (Fender)

Yeah, I only have one amp for my subs and it is grounded good with a 8 gauge wire. I don't think that is the problem. I think it is something in the engine compartment. What else do you think it might be?

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Cyberstang5.0
1992 Mustang GT 5.0

Do lights flicker? (doesn't really matter though)

Could be the voltage regulator not allow alternator to properly charge battery. But I assume you have internal regulator in alt so maybe not.

You can go to Auto Zone and they should be able to give you a FREE electrical systems diagnostic (includes alt, battery, volt. regulator).

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351W-powered 1979 Ford Mustang notchback
Stock 5.8L under 4" cowl, C4 w/ shift kit
Holley 750 cfm, Edelbrock Performer RPM intake
1 5/8" MAC shorty headers, Al driveshaft
2.5" Off road H-pipe, 2-chamber Flowmasters
Front: 225/60/15, Rear: 255/60/15 Eagle GT II
Weld wheels (15x6;15x8), 8.8" Rear w/ 3.55s
14 x 4” K&N air filter (getting the Xtreme setup someday) http://www.mustangworks.com/msgboard/cool.gif

"Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body

The lights dim at ldle but that is it. They turn on bright when my car is above idle. I will check out Autozone. Thanx

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Cyberstang5.0
1992 Mustang GT 5.0