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Lotus Service Notes Section EMN
Page 21
function of the regulator is to maintain a constant pressure differential across the injectors at all times. i.e. a
constant difference between fuel pressure supplied to the injector, and inlet manifold pressure at the port
injector nozzle. By using an intake plenum pressure signal to supplement regulator spring pressure in the
valve, the valve is able to regulate fuel supply pressure in accordance with engine load. The non-adjustable
pressure regulator is factory set to approximately 3.0 bar, and is serviced as a complete assembly.
To check the fuel pressure:
i) Relieve fuel pressure as detailed above.
ii) Connect fuel pressure test gauge T000T1386 into the supply line between the fuel filter and fuel rail using
adaptor T000T1387
iii) Disconnect the vacuum hose between the pressure regulator and the intake plenum.
iv) With the engine idling, the pressure gauge should read 2.9 - 3.1 bar.
If below specification, progressively restrict the fuel return line between regulator valve and tank.
- If the specification can then be achieved, the regulator valve is faulty;
- If this makes little or no difference, the fuel pump may be restricted or faulty.
If above specification, the regulator valve may be faulty.
v) With the engine still idling, re-connect the vacuum hose to the regulator valve. The pressure should drop
to approximately 2.2 bar.
- If the pressure does not drop, check the hose for kinking or blockage, or replace the regulator valve.
vi) Switch off the ignition and observe the pressure drop after one minute. Pressure should not drop by more
than 0.7 bar.
- Too great a pressure drop may be caused by (a) faulty regulator valve; (b) faulty non-return valve in
the fuel pump; (c) leaking injector
- If clamping off the return hose reduces the pressure drop, a faulty regulator valve is indicated.
- If clamping off the supply hose reduces the pressure drop, a faulty fuel pump is indicated.
- If clamping off both hoses does not reduce the pressure drop, a leaking injector is indicated.
vii) To check that the pump has sufficient reserves of delivery for full demand conditions, progressively
clamp off the return hose with the pump running. The pressure should increase by approximately 2 bar.
CAUTION: Only clamp the return hose momentarily and observe the gauge to ensure pressure
does not exceed gauge capacity.
Test gauge T000T1386
Adaptor T000T1387
Fuel filter
Fuel feed hose em209