A
fuel pump is a frequently (but not always) essential component
on a
car
or other
internal
combustion engined device. Many engines (older motorcycle engines
in particular) do not require any fuel pump at all, requiring only
gravity to feed fuel from the fuel tank through a line or hose to the
engine. But in non-
gravity
feed designs, fuel has to be pumped from the
fuel
tank to the engine and delivered under low pressure to the
carburetor
or under high pressure to the
fuel
injection system. Often, carbureted engines use low pressure
mechanical pumps that are mounted outside the fuel tank, whereas fuel
injected engines often use electric fuel pumps that are mounted inside
the fuel tank (and some fuel injected engines have two fuel pumps: one
low pressure/high volume supply pump in the tank and one high
pressure/low volume pump on or near the engine).
Please just read this for better understanding:-
www.airtexproducts.com/AIRTEXpdfs/Airtex_TTS_2008.pdf
In many modern cars the fuel pump is usually electric and located
inside of the
fuel
tank. The pump creates positive pressure in the fuel lines, pushing
the gasoline to the engine. The higher gasoline pressure raises the
boiling point. Placing the pump in the tank puts the component least
likely to handle gasoline vapor well (the pump itself) farthest from the
engine, submersed in cool liquid. Another benefit to placing the pump
inside the tank is that it is less likely to start a fire. Though
electrical components (such as a fuel pump) can spark and ignite fuel
vapors, liquid fuel will not explode (see
explosive
limit) and therefore submerging the pump in the tank is one of the
safest places to put it. In most cars, the fuel pump delivers a constant
flow of gasoline to the engine; fuel not used is returned to the tank.
This further reduces the chance of the fuel boiling, since it is never
kept to be controlled via
pulse-width
modulation of the pump voltage.
[1]
This increases the life of the pump, allows a smaller and lighter
device to be used, and reduces electrical load.
Fuel injected cars have an ECU (
Electronic
Control Unit) and this may be programmed with safety
logic
that will shut the electric fuel pump off, even if the engine is
running. In the event of a collision this will prevent fuel leaking from
any ruptured fuel line. Additionally, cars may have an inertia switch
(usually located underneath the front passenger seat) that is "tripped"
in the event of an impact, or a
roll over valve, that will shut
off the fuel pump in case the car rolls over.
Some ECU's may also be programmed to shut off the fuel pump if they
detect low or zero oil pressure, for instance if the engine has suffered
a terminal failure (with the subsequent risk of fire in the engine
compartment).
The fuel sending unit assembly may be a combination of the electric
fuel pump, filter, and the electronic device used to measure the amount
of fuel in the tank via a float attached to a sensor which sends data to
the dash mounted
fuel
gauge.
Good luck and do rate this solution.
let me know if you have any more questions. good luck
The top gear timing marks are aligned with the surface of the valve cover. The point on the cover should align with the TDC groove on the pulley.
