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Lotus Elise / Lotus Exige. Instruction - part 67

Page 3

Lotus Service Notes

Section LK

LK.1 - GENERAL DESCRIPTION

The 10.6 U.S. gall. (40 litre) fuel tank is fabricated from stainless steel, and is mounted within the chassis

crossmember between the passenger compartment and engine bay, and is secured against foam mouldings

by two support brackets from beneath. The fuel ﬁller neck connects with the right hand top of the tank, which

incorporates an Onboard Refuelling Vapour Recovery (ORVR) system operating on cars prior to '06 M.Y. as

follows:

In order to ensure that fuel vapour displaced from the tank during the course of ﬁlling is cleansed by the

charcoal canister before venting to atmosphere, a liquid seal is used to close off the ﬁller neck from escaping

vapour. The ﬁller tube extends within the tank to within 10mm of the bottom surface, such that the end of the

tube is submerged in liquid fuel under all normal circumstances. A one way valve incorporated at the base

of this fuller tube allows fuel to ﬂow into the tank, but prevents backﬂow into the ﬁller tube. When the tank is

being ﬁlled, displaced vapour from within the tank is vented through a Fill Level Vent Valve (FLVV) mounted

in the top of the tank, to the charcoal canister. Additional venting also takes place via a port in the top plate

of the fuel pump, from where it is routed through a roll-over valve (to prevent fuel spillage in case of vehicle

inversion) mounted on the centre top of the tank, before joining the pipe between FLVV and canister. A 3mm

oriﬁce in the ﬁller pipe just below the top surface of the tank, allows the ECU to run fuel system integrity tests

as required by OBD3.

In order to meet LEV2 emissions criteria, the fuel system was revised for '06 M.Y. Whilst the principle of

operation remains unchanged, in order to reduce the potential for evaporative emissions, the roll over valve,

and its connection with the ﬁll level vent valve, have been moved inside the body of the fuel tank, evidence of

this conﬁguration being provided by a bulge in the tank top surface. The breather port on the fuel pump top

plate is connected back into the tank via a spigot on fuel tank top.

When the fuel reaches a speciﬁed level in the tank, a bouyant ball in the FLVV seals off the breather ap-

erture and causes a pressure rise in the ﬁller neck to shut off the delivery discharge nozzle. Full tank capacity

has now been achieved. It is

NOT recommended to attempt to ﬁll the tank beyond this level.

The fuel pump/fuel gauge sender unit is mounted into the left hand top surface of the tank, and includes

a submerged turbine type pump which draws fuel through a strainer 'sock' for delivery through a non-return

valve, integrated fuel ﬁlter and a pressure regulator valve to the outlet port. A fuel supply pipe is clipped to the

pump outlet port and is routed through the rear wall of the fuel tank bay, to feed the fuel rail for the four fuel

injectors at a pressure of around 325 kPa. The single line fuel system eliminates fuel circulation back to the

tank, resulting in reduced fuel tank temperature and evaporative emissions.

Canister vent close valve Air ﬁlter

Float level vent valve

Roll over valve

To fuel tank

breather port Charcoal canister

To engine

intake plenum Vapour management

pl4405mtc

valve

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Lotus Service Notes

Section LK

When the ignition is ﬁrst 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 the ECU receives a crank signal.

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 the FLVV and fuel pump top plate as previously described.

The purge port of the canister is routed through a solenoid valve mounted on the inlet manifold, to a port on

the intake plenum. The evaporative emissions control system prevents untreated fuel vapour from the tank

reaching the atmosphere, by absorbing the tank vapour in a bed of activated charcoal in the canister. When

the engine is running, the engine management ECU opens the Vapour Management Valve (VMV) 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.

LK.2 - FUEL FILLING

Fuel Requirement

USE UNLEADED PREMIUM GRADE GASOLINE.

Use only unleaded gasoline meeting ASTM speciﬁcations. Use of fuels not meeting ASTM speciﬁcations

could cause poor performance and increase emissions.

For optimum vehicle performance and fuel economy, the use of super or premium unleaded gasoline, with

a minimum octane rating of 91 (RON+MON)/2 is recommended. Where super or premium fuel is not available,

the Elise will operate satisfactorily on unleaded gasoline having a minimum rating of 87 (RON+MON)/2, but

vehicle performance and economy will be reduced. 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, the cause

should be ascertained without delay.

The use of good quality fuels containing proper detergent additives is advised for good performance and

emission control.

Do NOT use leaded fuel: damage caused by the use of leaded or other improper fuel is not covered by

Fuel pump inertia switch

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Lotus Service Notes

Section LK

the New Vehicle or Emission Control System Warranty. Leaded fuel will damage the oxygen sensor as well

as contaminating the catalytic converter, the effectiveness of which decreases after as little as one tankful of

leaded fuel.

Gasolines Containing Alcohol - Some gasolines sold at service stations contain alcohol although they may not

be so identiﬁed. Use of fuels containing alcohol is not recommended, unless the nature of the blend can be

determined as being satisfactory.

Gasohol - A mixture of 10% ethanol (grain alcohol) and 90% unleaded gasoline may be used in the Lotus

Elise. If driveability problems are experienced as a result of using gasohol, it is recommended that the vehicle

is operated on gasoline.

Methanol - Do not use gasolines containing methanol (wood alcohol). Use of this type of alcohol can result in

vehicle performance deterioration and damage to critical parts in the fuel system. Fuel system damage and

vehicle performance problems, resulting from the use of gasolines containing methanol, may not be covered

by your vehicle warranty.

Fuels Containing MMT - Some North American fuels contain methylcyclopentadienyl manganese tricarbonyl

(MMT), which is an octane enhancing additive. Such fuels may damage the emission control system and are

NOT recommended.

Diesel - The Lotus Elise will not operate on diesel fuel.

Fuel Filling

WARNING: Be aware of the danger of explosion when dealing with petrol and its attendant fumes. Be-

fore 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.

Filler Cap: The fuel ﬁller cap is located in the right hand rear quarter panel, concealed beneath a spring loaded

ﬂap. To remove, pull open the ﬂap and turn the cap anticlockwise. As the cap is turned, any slight pressure dif-

ferential between the tank and atmosphere will be released, and a brief hiss may be heard, which is completely

normal. Note that the cap is tethered by a short strap to protect against loss.

To reﬁt, place the cap into the ﬁller neck and turn clockwise until the ratchet mechanism clicks several

times. Push the ﬂap closed.

Filling Procedure: Insert the pump nozzle fully into the neck, and ﬁll until the auto-shut off mechanism is trig-

gered. Do not attempt to ‘brim’ the tank to the top of the ﬁller neck, as expansion of the fuel due to temperature

change (cold underground fuel storage) may cause ﬂooding of the fuel tank breather system charcoal canister,

or spillage of fuel. The useable fuel tank capacity is 10.6 U.S. gall. (40 litres).

LK.3 - PRECAUTIONS

The fuel line between pump and injector rail, and the injector rail itself, contain pressurised fuel both when

the ignition is switched on, and for a period after switching off. This feature aids engine starting by reducing

the time needed to build up operating fuel pressure, and by inhibiting the formation of vapour pockets in the

supply line of a stopped hot engine.

WARNING:

To minimise the risk of ﬁre and personal injury, relieve the fuel system pressure before servicing

any part of the fuel supply circuit. See ‘Fuel Pressure Relief Procedure’ below.

ii) To reduce the possibility of sparks occurring when a fuel line is disconnected, or when fuel vapour

is present, the negative battery cable should be disconnected before work is commenced.

iii) When fuel lines are disconnected, absorb any escaping fuel in an absorbent cloth and dispose of

safely.

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Lotus Service Notes

Section LK

Fuel Pressure Relief Procedure

This procedure should be used prior to disconnecting any part of the fuel line.

Pull out the fuel pump fuse (on the left

hand side of the engine bay bulkhead, as

shown), start the engine, and run until it

stops from starvation. Crank the engine

for a further few seconds.

If the engine is a non-runner, pull out the

fuel pump fuse, and crank the engine

for 20 seconds to minimise residual fuel

pressure.

Disconnect the battery.

It is recommended ﬁrst to release the

quick ﬁt connector located to the rear of

the coolant header tank:

Release the retaining clip securing the

pipe joint to the header tank bracket.

Slide the orange coloured safety lock to

allow access to the connector release

buttons.

Surround the pipe joint with a shop towel

to absorb fuel contained in the pipework

before pressing the release buttons and

separating the joint.

WARNING: Be aware of the possibility of full

pressure retention in the fuel line caused by

a system fault.

Before re-making the joint, ensure that the or-

ange safety lock is ﬁtted onto the pipe connector

in the orientation shown in the illustration.

Push the male pipe end fully into the female

connector until a click is heard. Pull on the pipe

to ensure complete engagement.

Slide the orange safety lock over the connector

to prevent accidental pressing of the release

buttons.

Secure the pipe/connector using the pipe clip

on the header tank bracket.

LK.4 - FUEL TANK

The 10.6 U.S. gall. (40 litre) stainless steel fuel tank is mounted within the chassis crossmember between

the passenger compartment and engine bay, and is secured against foam mouldings by two support cradles from

beneath. The fuel ﬁller connects with the right hand top of the tank, and the fuel pump/fuel gauge sender unit

is mounted into the left hand top surface. A removeable panel is provided in the top of the chassis crossmem-

ber in the cabin, and provides access to the fuel pipe connections and harness connector. If the pump/gauge

sender unit is to be replaced, the tank must ﬁrst be removed from the chassis.

Fuel pump

fuse (20A)

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Fuel pipe to

Orange engine

safety lock

Fuel pipe

from tank

Release

L64

button

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