Lotus Service Notes
Section LJ
Page 3
LJ.1 - GENERAL DESCRIPTION
The 43.5 litre fuel tank is fabricated from Neotec coated steel, and is externally powder coated for further
corrosion resistance. The tank is mounted within the chassis crossmember between the passenger compart-
ment and engine bay, and is secured by two support brackets from beneath. The fuel filler neck connects with
the right hand top of the tank, with the filler breather pipe routed to the centre, and the fuel pump/fuel gauge
sender unit mounted into the left hand top surface. The modular fuel pump/sender assembly includes a
submerged turbine type pump with non-return valve, integrated fuel filter and a pressure regulator valve, to
supply a single line fuel rail for the four fuel injectors at a pressure of around 325 kPa. The single line fuel
supply eliminates fuel circulation back to the tank, thus reducing fuel tank temperature and evaporative emis-
sions.
When the ignition is switched on, the engine management ECU energises the fuel pump for a period of
about 3 seconds to prime the system before switching off. If a signal from the crankshaft sensor indicates that
the engine is being cranked or is running, the fuel pump feed will be maintained. The pump is switched off
immediately when the ignition is switched off, or about 3 seconds after a stall. Note that if coolant temperature
at the time of ignition switch off is over 88°C, the ECU remains powered for a period of 20 minutes to allow for
heat soak management (see sub-section KH.5). Re-energising the ignition during this period will not run the
fuel pump until a crank signal is received.
A safety inertia switch is incorporated into the fuel pump electrical circuit, and operates in a severe impact
(indicative of a vehicle collision) to switch off the fuel pump feed and minimise the fire risk. The switch is
located in the engine bay on the inner face of the left hand chassis siderail, and is reset once tripped, by
pressing the rubber button on the top of the switch.
An evaporative emissions 'charcoal' canister is mounted at the right hand front of the engine bay and is
connected to the air space inside the fuel tank via a port in the top plate of the fuel pump assembly. The
connecting pipe is routed through a roll over shut off valve mounted by the canister, to protect against fuel
spillage in case of vehicle inversion. The purge port of the canister is routed through a solenoid valve mounted
on top of the canister, to a port on the inlet manifold. The evaporative emissions control system prevents
untreated fuel vapour from the tank reaching the atmosphere, by absorbing the tank vapour in a bed of acti-
vated charcoal in the canister. When the engine is running, the engine management ECM opens the purge
solenoid valve and allows intake manifold depression to draw fresh air through the canister, purging absorbed
fuel from the charcoal, and consuming the resultant vapour in the normal combustion process. In this way, the
charcoal bed is 'cleaned' ready to absorb more tank vapour.
LJ.2 - FUEL FILLING
Fuel Requirement
Use only UNLEADED fuel with a minimum octane rating of 95 RON (‘Premium’ unleaded in U.K.) or
higher for optimum engine performance. Using fuel with a lower octane rating may cause knocking (pinking)
which, if severe, can cause serious engine damage. Light knocking may occasionally be heard for short
periods when accelerating or driving up hills, and this should cause no concern, although using a lower gear
would be advised. If, however, persistent heavy knocking is heard when using the specified fuel, diagnosis of
the cause should be undertaken without delay.
Note that the filler neck is restricted in size so that only the smaller diameter nozzle used on unleaded
petrol pumps may be inserted. The use of leaded fuel or lead replacement petrol (LRP) would cause irreparable
contamination of the catalytic converter and of the exhaust gas sensor used by the computer controlled engine
management system.
Fuel Filling
WARNING: - Be aware of the danger of explosion when dealing with petrol and its attendant fumes.
Before stopping at a filling station, switch off mobile phones, ensure that all cigarettes are extinguished
and that no naked flames or other potential ignition sources are present. Switch off the engine before
refuelling.
- Remove the filler cap slowly to allow any pressure to bleed off gradually. Hasty removal may result
in a small amount of fuel spray with a possible health or fire hazard.
Filler Cap: The key locking filler cap is located in the right hand rear quarter panel: