Lotus TURBO ESPRIT Service Manual page 398

Page
. .
26
SECTION LD
LD.
21
-
ENGINE
WARM UP
S1
Engine Cranking
As
soon as engine cranking takes place, the rpm relay switches on the fuel pump
and the system
i s
pressurised to
6.5
bar main primary pressure. Air induced into
the engine moves the airflow sensor which opens the fuel control valve and allows
fuel to be delivered to the injectors. I n addition, fuel i s supplied by the cold start
injector for a period controlled by the thermal time switch. Air
b
-passes the throttle
r
butterflies via the auxiliary air valve and a/c idle up solenoid va ve.
Cold Run
-
Below 35' C
Oil
Temp.
When the engine starts, the cold start injector closes,
if
i t has not already done so,
but air continues to flow via the auxiliary air valve, which closes as the engine warms.
The ignitionsolenoid directs
a
vacuum pump supply to the throttle iacking capsule, and
to the thermal ignition valve which itself directs the supply to the distributor advance
capsule.
a
he
control pressure set by the warm up regulator, i s low, but increasing as the engine
warm.
The frequency valve i s set to run open loop
@
75% duty cycle rate.
Cold Run
-
Above 3 5 ' ~
Oil
Temp., Below 5 3 ' ~ Water Temperature
As
35' C o i l temperature
is
reached, the E.C
.
U
.
switches the frequency valve to run
'closed loop' (i .e. controlled by Lambda sensor
@
around 50% duty cycle for
L
=
1).
Cold Run
-
Between 53O and 70° C Water Temp,
When 53O C water temp. is reached, the thermal ignition valve cuts off the vacuum
pump supply to the
D
.A .C
.
and connects i t with the throttle edge drilling.
Normal Running
-
Above
7 0 ° C
Water Temp.
When 700 C water temp. i s reached, the ignition solenoid cuts off the vacuum pump
supply to the throttle jacking capsule.
The a/c idle up solenoid valve opens only at idle with the compressor operaying.
LD 22
-
FUEL
SYSTEM PRECAUTIONS
Always ensure absolute
cleanliness when working on any part of the fuel system.
Thoroughly clean around any joint before disconnecting a component.
Pressure i s maintained i n the fuel system after the ignition i s switched off by the
action of the fuel accumulator, primary pressure regulator and control pressure
shut-off valve. Therefore whenever disconnecting a fuel system joint, take care
to use an absorbent cloth to protect from spray, and soak up the small amount of fuel
released.
Take a l l necessary precautions to prevent sparks occuring whilst a fuel joint i s
disconnected.
Ensure that new sealing washers and gaskets are used on re-assembly, and that a l l
joints are torque tightened i n accordance with Section LD
25.
,
When fuel system tests are being performed involving the collection of fuel from
fuel pumps, fuel injectors etc
.,
the very strictest precautions must be tbken to prevent
sparks occuring i n the vicinity of the working area.
Any
electrical switching necessary
i n the course of these tests should be performed by the ignition switch, or fuel pump
inertia switches
.'
Ersure the working area is well ventilated