What could possibly cause two consecutive fuel pump modules to fail?

[freezer0909]

I have a 07 Chevy Cobalt. The original fuel pump in the car had a gas leak due to a defective plastic part that cracked, so I took the car to a local Chevrolet dealer and had the fuel pump module replaced under special coverage at the beginning of February. Soon after the replacement, I noticed some strange signs that I had never seen before. If the the car was parked overnight or for a long time, and I started the car for the first time, there was a strange noise coming from the rear of the car near the gas tank when the fuel pump was engaged, and it took much longer for the car to start than usual. So I suspected that there was some kind of problem with the new fuel pump module. And eventually on March 30, 2014, the fuel pump suddenly failed when I tried to start the car, and the car wouldn't start. So I had no choice but to have it towed to the dealer. They checked it, but did not investigate why it failed, only simply replaced the fuel pump with a new one. And they told me that it could be a defective fuel pump. I believed them and thought to myself that this time it should be alright. I was wrong. A couple of days ago, the exact same signs showed up from the second fuel pump they put into my car: there was a sharp noise coming from the rear when the fuel pump was engaged for the first time, and it took much longer to start the car. From my experience I know that the second fuel pump is about to fail, too, just like the first one. The first one lasted less than two months, not sure how long the second one is going to last.

Right now I don't think it is a coincidence that the two consecutive fuel pumps are both defective parts. I think there must be something that caused them to fail. So what in the car could possibly cause the fuel pumps to go out on me? The car's relatively well maintained and has 70,000 miles on it. Or maybe the entire batch of fuel pumps the dealer ordered are defective?

 

[zora]

did the dealer use a factory part? how are your driving habits, how low do you let the gas gauge go before refilling? if you wait till the gauge is at E the pump will overheat and fail.

 

[freezer0909]

did the dealer use a factory part? how are your driving habits, how low do you let the gas gauge go before refilling? if you wait till the gauge is at E the pump will overheat and fail.

I'm not sure if the dealer used factory parts or not, but I guess they did, since I can find them on Chevrolet's dealer locator website.
I usually let the gauge go completely empty before refilling, but I don't think that is the problem. Even if it is detrimental, the condition of the fuel pump module wouldn't deteriorate so fast, right? And there are at least two gallons of reserved gas in the gas tank in most cars nowadays. That is, even if the gauge indicates the tank is empty, there are actually still two gallons of gas in the tank.
What kind of fuel pump can only last two months anyway?

 

[zora]

you are burning out the pump by repeatedly going to empty. The gas is used to cool the pump if there is insufficent gas to keep the whole pump covered it will overheat and prematurely fail.

 

[Chuzz]

I agree with zora, it's not the fuel pumps that are defective, you're killing them by burning them out. IF the dealer replaces a third one for you, I'd suggest you never let the car get below 1/4 tank of gas in the future. I never let any of my vehicles get that low. I've got a 99 Grand Caravan with 205,000 miles on the original pump. It's never been below 1/4 tank of gas.See what I mean?

 

[freezer0909]

I agree with zora, it's not the fuel pumps that are defective, you're killing them by burning them out. IF the dealer replaces a third one for you, I'd suggest you never let the car get below 1/4 tank of gas in the future. I never let any of my vehicles get that low. I've got a 99 Grand Caravan with 205,000 miles on the original pump. It's never been below 1/4 tank of gas.See what I mean?

I only refilled like once or twice during the lifespan of the first fuel pump. Am I to understand that because I did not refilled until the tank is empty once or twice, the pump couldn't hold any longer and failed?

 

[zora]

you are to understand that repeatedly lettering the tank run to empty will have a detrimental effect on the lifetime of the pump. Nobody on this site examined your pump to determine the true cause of its failure. You asked for a cause you were given one you are free to do what you will with the information.

 

[freezer0909]

you are to understand that repeatedly lettering the tank run to empty will have a detrimental effect on the lifetime of the pump. Nobody on this site examined your pump to determine the true cause of its failure. You asked for a cause you were given one you are free to do what you will with the information.

Thank you for your info. But please read this thread I found on the net:

http://community.cartalk.com/discussion/2132213/running-close-to-empty-will-ruin-fuel-pump/p2

There was quite a debate here.

 

[zora]

yes that was quite a debate but did not resolve your issue. Either you have incredibly bad luck in having two bad pumps or running low is not a wifes tale. The only other possibility is excessive voltage caused by a bad alternator but you would be experiencing many light bulb failures along with the pump failures.