Lotus TURBO ESPRIT Service Manual page 445

Page
7 2
SECTION LD
24.
Engine Ovenpeed/Fuel Pump Failure Module
Location: Top of right hand tank board. (Under filler neck)
-
Mating connector colour: Natural
.
Additional information see LD
3.
The module senses low tension ignition pulses and supplies a negative to the
fuel pump control relay winding.
I n the event of excessive engine speed (7,000
2
50
R.P.M=) this feed i s removed
thereby stopping the injection system operating and limiting engine
R. P. M.
Also i n the event of one of the two fuel pumps failing to operate the maximum
engine
R.P.M.
i s restricted to 2,800
+
50
R.P.M. This
i s achieved by
monitoring the current drawn by e a ~ h - ~ u m ~ and removing the negative to
the fuel pump control relay windings at 2,800
+
50
R. P.M.
i n the event of
one pump failing to draw any current. ~herefore any part of the circuit between
the module and the pump, going open circuit, w i l l be detected and engine
R. P.M.
restricted. (This unit w i l l therefore sense blown fuse, broken or disconnected
fuel pump wiring
.)
Disconnection of the module w i l l not allow the fuel pumps to operate. Single
pump failure may cause the fuse i n the other pump circuit to blow due to the
increased load imposed on i t (dependent on position i n which failed pump fails).
This circuit is designed as a "get you home" aid i n the event of failed fuel pump
but the vehicle require attention to the fuel pump system as soon as possible.
25.
Fuel Pump Control Relays
( 2 )
Location: Coil box
Mating connector colour:Black
Double contact relay (schematic a s shown i n item
1 )
.
Controlled
by
the engine ovenpeed/fuel pump failure module, overboost switch
and inertia switch. Switches positive feed, via
15
amp fuses to individual
fuel pump circuits
.
26.
Overboos t Switch
Location: Coil box
Mating connector colour: White. Additional information see LD
3.
Supplies, v i a terminal
8%
of the
R . P : M .
relay, a positive feed to the winding of
the fuel pump control relay.
This feed i s removed, thereby de-energising the fuel
pumps, i n the event of an engine fault condition of excessive turbo boost pressure.
Fuel Enrichment Module
Location: Top of right hand fuel tank board.
Mating connector colour: White. Additional information see LD
27
--
10
Senses engine speed of
3250
rpm via negative feed from ignition coil, and
switches ignition feed to operate relay coil and close relay contacts..
This
:
provides earth signal to
E .C
.U
.
terminal
7.