I have a 94 Z28 that has a voltage drop (to around 11 or so) when I turn on any combination of the AC, headlights, and rear window defogger. I had a local auto parts shop test my alternator in the car and it tested at 25 peak Amps (well below the 140 it is rated for). I replaced the alternator with a remanufactured AC-Delco and it read 19 Amps with there testing equipment. Since I had the original out of the car they tested it inside their shop and it tested fine. I then thought it may be a bad battery. It is a 10 month old Maxx-75 battery from Walmart. I figured it wasn't the battery because the voltage drop is while the car is running but still took the car to Wal-Mart. The battery tested good and bad both inside and out of the car at different times at 2 different Wal-Marts. I ended up having the battery replaced for free under warranty because the battery was in question. Well, I still have the voltage drop when I turn on the accessories. I had a local dealership replace my starter a month ago because the solenoid didn't disengage and it fried the motor literally. After all this, what do you guys think is the problem? A bad ground? Something the dealership did when they replaced the starter? Thanks in advance for any thoughts.

 

Anyone?

 

Does it drop to 11 on your dash gauge or on the test equipment or both?

 

I know it drops for sure on my gauge. Not sure about the voltage on the test equipment. I only know the test equipment showed the system putting out 25 Amps when it put my engine under a load (I guess that is what they call it).

 

Do you have an underdrive pulley and is the voltage drop at idle Rev the engine to about 1500-2000, if its go to 13.4-13.9 there is nothing wrong

 

mine is doing the same thing I have also had it tested with good and bad results. does yours charge fine when you first start it up then when it gets warm it starts acting up? I did move my battery to the sparetire well.(thats when I noticed my problem) I even put a ground strap on with no luck. and had the alt. rebuilt(one I had already) I have a brand new red top optima 720 CCA battery and I am about to give up on it. I noticed when my fans or any other high power acc. is on it will drop down real low. even If I rev it up it goes up slitghly but not what I should. And sometimes if I turn my fog lights on then turn it the rest of the way it the headlights wont pop up...Good Luck if I found out anything I will let you know.

 

funina91ss: My car starts fine. I only see the voltage drop when I turn a few things on to put a heavier load on the system.

Zjoker: I don't have an underdrive pully. The voltage drop is only at idle but in 9 years of owning and driving this car, I have never seen this happen. The voltage does go back up to normal when I rev the engine.

 

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