lavamadness

This may be a dumb question, but can low battery voltage kill a fuel pump? My alternator isn't big enough for my stereo, and often when I'm driving the voltage gauge in my car is often reading 10 or 11ish. My fuel pump went last week, and the thought just occured to me. I was just curious.

Vader

Most motors (DC, universal, and even many induction types) are constant HP designs. That generally means a relatively constant input wattage. If you understand a few things about electric motors, you will know that with these type motors, lower input voltage can lead to an increase in input current as the motor tries to develop the same amount of necessary output power. The higher current can damage commutators, armature windings, brushes, and any connections along the way from the supply to the motor.

I'm nearly certain that I experienced the same syndrome on a '97 GMC truck. Before it was brought to me, it had two replacement pumps. That's the original pump, plus two more. It had eaten another pump, and I replaced it. After about six months, the pump was again unable to produce adequate pressure. I performed the full diagnosis of the system that I SHOULD have done in the first place. The pump was only getting about 10.8V at the tank connector, and I discovered a connector in the harness that had marginal connections and signs of heating. I replaced the connector and pump, cleaned up the grounds - no more problems.

Moral? If you don't want to become really proficient at changing your fuel pump, fix the electrical problem.

lavamadness

Thanks for the reply and confirming my suspicions. I've known I needed a new alt for a while now... just didn't make it a priority. Lesson learned.