Havnt had the car too long so maybe this is normal?

I have an aftermarket fuel pump and wire harness. You can hear the pump running.

If i put my foot on the brake when the car is at idle, the lights will dim, the rpm's will drop very slightly, and the fuel pump will drop in pitch. Then it will come back up to normal. Its annoying.

Just put a new alternator in a few days ago because the voltage was wiggling around and getting below 13. Maybe the battery is bad? Not sure...

Maybe the pump draws alot more juice than a stock pump.

 

sounds like the battery . take it to the auto store and have them test it .

 

ill try to do that tomarrow.


the rpm drop is so little that it may even be my imagination. but the light dimming and fuel pump drop, is very annoying.

 

I would check the wiring between the battery and alternator first. Do a voltage drop test (pos batt terminal to B+ on alt, and then neg batt post to alt casing) and see what kind of results you get. Should be less than .5V on the positive side and .2V on the negative side.

 

well, i do have a multimeter in my work van, but im not sure how to use it to check my car.

 

when i changed the alternator, i turned the nut holding the battery cables but the cables turned with it. There was no slack so some of the jacket pulled back off the black cable but I dont think much damage was done to it.

I wonder if they are that sensitive. guess ill have to figure how to use my volt meter thingy. it has 2 probes and reads amps ohms voltage and all the goods.