Fuel Pump is gone for the 3rd time????

My fuel pump is gone for the third time. When it first went bad, I put a new one. It gone bad after three months for the second time. I put a used part this time. Then it had gone bad for the third time after two months. Mechanic told me that it does not have enough pressure. But the guy whom I got the used fuel pump said, fuel pump either works or not. And he said I have another problem with the car. I will go mad because I changing the fuel pump all the time, yet no solution. It goes bad after 2-3 months. I have no money left. Any ideas?? What can be wrong. Problems : Hard start, or stops after starting, doesnt take the fuel to accelerate, it accelerates with hesitation, shaking, it even stops at 30-40 mph (it happened on the highway), when i start the car at the park and heat it by pressing to the gas pedal, white smoke comes from the muffler with a smell and some noise (like pat, pat). Please help me??????

first, replace the fuel pump with a new unit. the tap tap tap is because youve run the engine too hard while it's cold!!! That is a dry lifter. Basically the rocker arm has no oil between it and it's mount. The simplest solution is to pull the valvecovers, use WD-40 and your fingers. Brake cleaner works too. get the little wheels so they rotate freely. Be careful not to get any in the engine, but you should empty your oil and flush a quart through after replacing the valvecovers using new gaskets.

Should I change the valve covers? (I am very unexperienced) Where are these valve covers? Can you explain it a little more? I can also tell this to the mechanic, If I can not do it.

To answer the question with the fuel pump, the system uses two circuits to deliver voltage to the pump. The first, which is monitored by the ECM, operates the pump for several seconds at key on, allowing the system to pressurize. It will then wait for an rpm signal to the ECM to turn it back on. This is operated by a relay operated by the ECM. The second, is the oil pressure switch on the block, which sends voltage to the pump directly, when oil pressure is above 5 lbs. This is a back-up circuit, in case the relay circuits fail for some reason. The ECM monitors the 12 circuit, checking for voltage at that point. If the relay responds and sends voltage to the pump, the ECM also gets the signal, smiles, and runs the pump. If not, the ECM frowns, sets a code and waits for the oil pressure to send the necessary voltage. The pump failure issue indicates several possibilities, insufficient voltage, indicating a drop somewhere between the battery and the pump, a defective ground, somewhere between the battery and the pump, or a blockage in the system, restricting fuel flow either into or out of the pump. Fuel starvation to the pump is hard on pumps since the fuel acts as a lubricant as well as an insulator. Food for thought. Ray

so, is it better to put the key in the on position and let the system pressurize before starting?

For what it's worth, my '89 LeSabre went through 3 "aftermarket" (read, "crap") fuel pumps--in about 2 years time--that were obtained from my local big-name auto parts outlet. When I hassled them and their parts rep about it, they said it was because I had "trash" in my tank. I might buy that on the first failure, but not on all three. When I finally ponied up the dough to get a real GM fuel pump, no more problem. So will never permit another aftermarket pump in my tanks. I also try never to drive with less than 1/4 tank of gas, esp. in the summer months; the fuel helps keep the pump cool in the tank, so I'm told. I always listen now for the brief "whirr" noise the fuel pump makes when I turn the key on before cranking, listening for that fuel system to pressurize like RABarrett was explaining. If it's not doing that, I'd be checking the pump's electrical circuitry. As to tman2093's question, I don't know if it's "better" to let it pressurize or not, but I always do, if for no other reason than I know my fuel pump is alive.

I cant see the harm in letting it pressurize, and you can call me tman :)