92 isuzu trooper. Fuse to the fuel pump keeps blowing. Why?

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92 isuzu trroper had a bad fuel pump. Relaced it. Got it running for about 30 seconds and then it died. Checked the fuel pump fuse under steering wheel and it blew. It had a 10 amp in. With the key off, i replaced it and blew again. Disconnected the fuel pump, replaced fuse and immediatly blew with the key off. Tried a few more times, and same result. Thank you for your time...