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Hello all, I'm new to this Forum, and I'm hoping I can get some clarity on my situation.  I own a 1985 Mazda RX-7 GSL-SE with the 13B motor.

I have just installed a brand new fuel sending unit into a replacement gas tank, however I'm experiencing a problem.  Anytime I turn my key to the ON position, the fuel gauge reads true.  But, when I start the motor, the fuel gauge drops lower; about 1/4 low from where the needle was before the engine started up.

I checked all my connections, and they look just fine.  The only thing I can think of why this is happening is that when the fuel pump starts up, it's sharing power from the fuel sending unit and causing a bad reading.

What could be my problem?