download After examining the fuel pumps returned under claim for the above
vehicles, it has been found that a high percentage of returns have no
operating fault found with them. The normal complaint is “not pumping”,
or “fuel starvation”. In some cases the fault may be cured when a new
fuel pump is fitted, but returns shortly afterwards. There are two
common causes of these symptoms on the vehicle, besides the fuel pump:
1) The Rubber Fuel Supply Pipe This may be perished or weakened,
resulting in a partial or total collapse of the internal bore,
restricting the fuel flow.
The perishing of the pipe can also lead to
air leaks on the suction feed to the fuel pump, so that the pump sucks
air as well as fuel, reducing the lift efficiency of the fuel pump. 2)
The In-Line Fuel Filter The filter should be changed at intervals of
20,000miles (32,000Km). Failure to do so will result in a build up of
sediment particles blocking the filter, reducing the fuel flow. This is
especially so on older vehicles where corrosion takes place within the
fuel tank and metal feed pipes. In order to ensure that the fuel feed
system operates at its full potential, it is recommended that both of
the above items are checked, and/or replaced, before fitting a new fuel
pump.