After replacing two short-lived Delphi fuel pumps from Summit Racing with a third from AutoZone (same model), I am now back to having a dead fuel pump for the third time in less than two months with maybe 3 miles of total driving. All three times the pumps worked when the Jeep was turned off only to not turn back on days later.
4a test light at the pump connector shows good power to that point when the key is turned on. And providing 12v power and ground directly to the fuel pump does nothing.
Either I am a very unlucky person, or something is killing them. But what could it be?
Given that you've tested for power at the pump connector and still face the same issue, there are a few possibilities to consider that could be causing early failures of the pumps:
Electrical Issues: Since you're getting power to the connector, check for voltage drops or bad grounds in the wiring harness. Poor ground connections can lead to increased resistance, which can cause the pump to overheat and fail prematurely.
Fuel Quality: Contaminated fuel can be harsh on fuel pumps. If there's debris or water in your fuel tank, it can lead to pump failure. Consider replacing the fuel filter and inspecting the tank for any foreign substances.
Fuel Pump Relay/Fuse: A malfunctioning relay or fuse could be causing intermittent power issues, which can lead to pump failure. Make sure these components are in good shape.
Overheating: Ensure that the fuel pump is getting adequate fuel supply, as pumps rely on fuel for cooling. If the tank is low or there's an issue with the fuel lines causing improper flow, it could lead to overheating and failure.
Voltage Regulation Problems: If your vehicle's voltage regulator is malfunctioning, it could be sending higher than normal voltages to the fuel pump, which can shorten its lifespan.
Default Mode: Some electronic problems may leave the pump in a default mode that runs it continuously even if it should be off, leading to burnout.
It might be worth taking a closer look at the complete fuel delivery system, including the wiring, connectors, and any potential performance issues. Also, consulting a professional mechanic could help in diagnosing underlying issues causing the failures. Best of luck!