Voltage/RPM Drop [Archive] - GrandAmGT.com Forum


View Full Version : Voltage/RPM Drop

10-17-2004, 03:46 PM
When my car is idling sometimes the RPM's and the Voltage will drop then come right back to normal. It happens randomly and only when I am like sitting at a traffic light or have it in park....I don't think it happens when the engine is cold either, only after it has run for awhile. I have a 2.4 so does anyone have any idea of what I should look at, or cheap things to replace to see if I can fix this problem before winter?

10-18-2004, 06:28 AM
When the RPMs drop, the voltage output will drop as well. Most autos will idle within so many RPMs. If you see a big drop though, something could be wrong.

Does your car idle rough? Do you have a big sound system?

If your car idles rough, something is up. If you have a big sound system, your alternator probably needs to be upsized.

10-18-2004, 07:47 AM
No the car idles fine but everyonce and a while will do that. No big stereo anymore so I know it isn't that...unless it wore down an the alternator or something. What cause the drop if it is normal though? Cause I havent ever experienced this before. When I drive back to my apartment I will see how many rpm's it drops.

10-18-2004, 07:52 AM
Get your battery tested, and most likely there is a problem with the altenator.

(I say get your battery tested because when a battery gets weak, it will not hold a charge well and the altenator gets overworked and starts to break down) Therefore you may need to replace the battery and the altenator.

ITs also not uncommonplace anymore to have the stock battery fail after only 3 years or so. A good factory battery or good aftermarket replacement often last at least 5 years before it goes south.