Lotus TURBO ESPRIT Service Manual page 392

Page 20
SECTION LD
LD.
18
-
VACUUM OPERATED
ENGINE
MANAGEMENT DEVICES
These include the Thermal lgnition Valve,
(T. I
.V
.)
lgnition Solenoid, and Throttle
Jacking ~ a ~ s " l e .
Thermal Ignition Valve (T.
I
.V
.)
The
T.l
.V. i s fitted into the inlet manifold water rail and controls the vacuum feed to
the distributor advance capsule
(D
.A.C.)
.
At water temperatures below 530 C, the
T. I
.V.
directs a vacuum pump feed to the distributor advance capsule to improve cold driveability,
but changes the feed above this temperature to a throttle edge drilling on no.
3
intake
tract.
lgnition Solenoid
&
Throttle Jacking Capsule
(T.
J.C.)
The ignition solenoid controls the vacuum supply to the throttle iacking capsule, and
i s
switched by an electrical feed from the high temperature switch, fitted into the inlet
manifold water jacket between tracts
1 & 2.
A t water temperatures below 7 0 ' Cthe high temperature switch supplies current to the
ignition solenoid, which then directs a vacuum pump fed to the
T.
J.C. to increase cold
engine idle speed. Above
7 0 '
Cthe solenoid
i s
de-energised and the
T.
J.C. connected
with the upstream throttle port.
LD.
19
-
AIR CONDITIONING IDLE UP SOLENOID
-
The purpose of the A/C idle up solenoid i s to maintain engine id1 e speed when the air
conditioning compressor i s operating.
'
The solenoid i s fitted on the
RH
fv'el tank board, and connected by hose between the
inlet manifold cold start air r a i l and the underside of the airflow sensor. The valve i s
of the 'normally open' type, and i s closed when the solenoid i s energised.
A t water temperatures below
70'
C the valve i s open a t a l l times, to aid cold
running and,-id1 lng
.
A t water' temperatures above
70'
c
the solenoid is energised
and the valve sh.uts
, If
however, the air conditioning compressor is opem ting,
the solenoid valve de-energf e s
. .
and
.
opens whenever engine speed i s below
1400
rpm..
(Controlled by the fuel by-pass relay).