FUEL PUMP

In Fiat Uno cars, a diaphragm type fuel pump was used, attached to the engine block and driven by a cam on the camshaft or intermediate shaft.

Checking the fuel pump

The cause of an inadequate fuel supply to the carburetor may be a failure of the fuel pump. So if there is "jerking” engine, caused by too poor power supply, then you should definitely check the fuel pump first before proceeding to the carburetor. The procedure is presented below.

■ Clean the filter under the cover of the fuel pump.

■ Tighten the screws that connect the two pump halves. None of the screws can be loose, as this could cause air to be sucked in.

■ The fuel lines to the pump must not be clogged or kinked. The cables must be checked most carefully.

■ Replace the fuel filter (if).

If these treatments don't help, then take it as follows: check the fuel level in the carburetor, measure the discharge pressure of the pump, repair it or simply replace it.

The pump discharge pressure should be 0.20…0,30 barium (200…300 hPa) at rotational speed 4000 rpm (as a minimum it is assumed

0,17 barium). To check the discharge pressure, a standard pressure gauge should be connected between the pump and the carburetor. Set the required engine speed and read off the pressure. The reason for the low pressure may be:

- damaged valve in the body (replace pump),

– ruptured diaphragm (replace the diaphragm).