Lotus 2004 Eleven Service Notes page 303

Lotus Service Notes
To Remove Pump/sender Assembly
1. Remove the fuel tank (see sub-section LJ.4).
2. Release the eight nuts securing the clamping ring, and carefully withdraw the pump assembly from the
tank. Immediately seal the tank aperture to reduce the fire hazard and prevent dirt ingress.
3. For permitted disassembly of the pump unit, refer to Toyota 2ZZ-GE Engine Repair Manual, publication
RM733E.
4. To refit the pump assembly, renew the rectangular section sealing ring before carefully feeding the sender
float arm in through the tank aperture. Orientate the unit with the breather spigot pointing inboard, and fit
the clamping ring with the location tab engaged with the recess in the pump top moulding. Fit and secure
the eight M6 washers and nuts.
5. Refit the fuel tank into the car (see sub-section LJ.4).
6. Connect the fuel feed pipe and retain with the spring clip. Connect the breather pipe to the spigot on the
pump top plate. Fit the harness plugs to the pump/sender connector, and to the pressure sensor.
LJ.6 - CHARCOAL CANISTER
In order to prevent fuel vapour venting from the fuel tank to atmosphere, the breather pipe from the tank
is routed to a canister filled with activated-charcoal, which absorbs and stores the fuel vapour when the engine
is stopped. When the engine is running, the canister is connected to the depression in the intake plenum via a
port on the inlet manifold such that fresh air is drawn through the canister to purge the charcoal of its absorbed
fuel, with the resultant gas then consumed by the engine in the normal combustion process.
Charcoal Canister
This is mounted at the right hand front corner of the engine bay via a bracket fixed to the bulkhead. Fuel
vapour from within the tank and collected from a spigot on the fuel pump/sender top plate, is routed via a
roll-over valve (to prevent fuel spillage if the car is inverted) mounted on the charcoal canister bracket, to the
canister port labelled 'tank'. This port is extended within the canister to the underside of the charcoal bed,
below which is a reservoir to collect any liquid fuel. A second port on the canister ('vent') connects the top side
of the charcoal bed to atmosphere. In this way, vapour from the fuel tank is cleansed of fuel by the charcoal
bed before venting to atmosphere.
The third, 'purge' port, controlled by a solenoid valve mounted on the air cleaner housing, connects the
underside of the charcoal bed with a port on the engine inlet manifold. The solenoid valve is opened during
certain engine running conditions in order to allow intake depression to draw fresh air through the vent pipe and
charcoal bed, cleansing the charcoal of fuel before consuming the resultant vapour in the normal combustion
process. In this way, the charcoal is prepared for further vapour absorption.
Control System
The canister purge valve is controlled by the engine management ECU, which keeps the valve closed
(unenergised) when the engine is cold or idling in order to protect the catalyst and maintain idle quality. At
normal running temperatures and engine speeds above idle, the ECU monitors other running conditions and
management system stati, and when appropriate conditions pertain, the ECU will apply a duty cycle to the
valve in order to regulate the amount of purging allowed dependent on the amount of vapour in the canister.
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Section LJ