Author Topic: Is this normal for fuel pump?  (Read 139 times)

Offline 3dachshunds

  • Motobrick Curious
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Is this normal for fuel pump?
« on: January 15, 2026, 11:22:34 AM »
Finally got new pump working, but still can’t get engine running. It appears fuel stream fuel streams inside tank when pump running. I am wondering if instead of building pressure on fuel rail, it churns fuel inside tank…
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  • 1992 BMW K75, 2013 Triumph Tiger 800 roadie

Offline Laitch

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Re: Is this normal for fuel pump?
« Reply #1 on: January 15, 2026, 02:47:09 PM »
Fuel sent through the fuel rail to the injectors that is unused returns to the tank under low pressure. In your Brick it likely spills from a metal pipe at the ceiling of the tank into the tank's fuel supply. It's possible that is the agitation you're seeing. Regardless, you must verify that all interior tank hoses are in good condition, that they attached firmly by fuel injection hose clamps to the pump and the fuel filter, and that the fuel filter isn't plugged. If you don't know the age of the fuel filter, replace it. The NAPA 3032 filter seems to perform satisfactorily for many forum members. I use the Mahle KL145.
After a few attempts at starting, remove the plugs and let us know it they're wet or dry.
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Offline Scott_

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Re: Is this normal for fuel pump?
« Reply #2 on: January 16, 2026, 10:47:27 AM »
Finally got new pump working, but still can’t get engine running. It appears fuel stream fuel streams inside tank when pump running. I am wondering if instead of building pressure on fuel rail, it churns fuel inside tank…
One way to check fuel to the rail, remove one of the lines at the rail and check for flow(into a safe container!!).
While at this point, if you disconnect the return line from the tank, you should be able to connect a pressure gauge to check that the pump is actually supplying enough pressure. The return line should connect from the front of the fuel rail, to the regulator(behind the throttle bodies), then connect to the tank.
If the pressure regulator on your bike has a vacuum line to it, it will cause the regulator to not regulate until the engine is running and supplying vacuum. You should still be able to measure the unregulated pressure.
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