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Can THIS happen?


gmrulz4u

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Is it possible for a certain electrical circuit of a car take MORE power than it's supposed to?

 

Say for example something's supposed to normally use 0.25volts, but for some reason it's draining 2.0volts, is this possible?

 

Because with my car, stepping on the brake pedal has always caused a large drop in voltage, like 2.5volts. And why is that when you're at a complete stop with your foot on the brake, it takes way more voltage than when I put the car in park? Is this normal?

 

Do all of your cars give better voltage readings when the car is idling in park versus idling in drive?

 

THANKS:o)

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Because with my car, stepping on the brake pedal has always caused a large drop in voltage, like 2.5volts. And why is that when you're at a complete stop with your foot on the brake, it takes way more voltage than when I put the car in park? Is this normal?

 

Do all of your cars give better voltage readings when the car is idling in park versus idling in drive?

 

THANKS:o)

 

Well, 2 things while in park....1- idle is a hair higher, for example my car idles around 650rpm's in drive, but about 750 in park. 2- basically this causes the drop in RPM's is that the transmission is not putting a load on the engine. Let me ask you, have you checked the tightness of the battery terminals and that theyre corrosion free? I had a loose negative terminal once, and the only problems it caused are a heavy voltage drop when the brakes were applied or the cooling fans came on...so much that the headlights momentarily blinked.

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Actually, you don't measure drain in volts, drain is measured in amps.

Everything in the car uses 12V (or whatever the battery/alternator is putting out). However, the variable is current. Some things drain more current. The only time a current drain results in voltage drop, is if the power source is too weak to supply the current needed.

 

So if stepping on the brake pedal causes voltage to drop 2.5V, that's due to the battery or alternator being unable to supply enough current to keep the voltage steady.

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MY car used to do the same and what the cause was a loose negative cable on the battery and positive bable that goes next to the fuel pump fuse was loose, i tightned both of them and problem went away.

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