fuel pump

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321gazza
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Post Tue May 01, 2012 7:15 pm

At what pressure does my intank fuel pump run at in psi please, its a 1992 318i.
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Billwill
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Post Wed May 02, 2012 7:59 am

321gazza wrote:At what pressure does my intank fuel pump run at in psi please, its a 1992 318i.
According to Haynes it is 3.0 bars which converts to 45.5 psi according to Google convert. :)
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Brianmoooore
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Post Wed May 02, 2012 10:33 am

The pressure it runs at is set by the fuel pressure regulator on the fuel rail above the inlet manifold on the engine. The pressure is marked on the regulator.
Note that this pressure is relative to that in the inlet manifold, so will only be three bar when the throttle is wide open. At part and closed throttle there will be a partial vacuum in the inlet manifold, and this will reduce the fuel pressure by the same amount.
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321gazza
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Post Wed May 02, 2012 8:30 pm

Running a swirl pot and will be using the main pump to feed the pot, have been advised the that would be ok but still would like to know the intank fuel pressure that gonna feed my swirlpot.
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Brianmoooore
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Post Wed May 02, 2012 10:51 pm

Pressure depends on the flow rate. High flow = low pressure, and vice versa.