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Author Topic: What's in a fuel pump  (Read 523 times)

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Offline Uniflow

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What's in a fuel pump
« on: January 16, 2013, 07:23:06 AM »


Ever wondered what was inside an EFI ( high pressure )  fuel pump? The fuel is run right through the electric motor, bushes, brushes and all !!! . The actual pump is the small bit at the left hand end of the motor shaft. This one failed due to bad mounting system ( on my part ) it had been rattling around for a while under the bike and finally wore through the outside casing ( fuel came squirting out ). Just thought it was interesting. This is a Bosch pump and has been filled with ethanol for two years now, this pumps insides are in good condition. This type of high pressure pump doesn't seem to have a problem with ethanol fuel. The end that does the pumping work is a positive displacement type with hardened rollers running in an offset hardened steel ring. You may not run this type of pump out of fuel as the fuel is used for lubrication and cooling. Hard case way of pumping fuel !!!!
Pressure is held constant by a relief valve at the end of the injector fuel rail ( usually about 45 psi)
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