Cold Starting Fuel Injection System Components; Maintenance Of Fuel Injection System Components - Triumph TR7 Owner's Manual

EMISSION AND EVAPORATIVE LOSS CONTROL SYSTEMS
Cold Starting Fuel Injection System Components
To assist cold starting, a separate cold start injector sprays a
fine jet of fuel against the air stream entering the plenum
chamber before fuel is added to il by the main inJeclors. The
cold start injector is energised from the engine starter motor
circuit and has In series with
it
a thermotime switch This
switch is dual activated by the engine coolant temperature
(heat) and a heater coil around a bi-metal strip (time), the coil
being again energised from the starter motor CIrCUit. The
purpose of the thermotime switch is to ensure that the cold
start Injector will not be energised when the engine is at
normal operating temperature or should the starter motor be
used for prolonged periods when the engine is below normal
operating term perature. Thus the switch prevents extra fuel
being supplied to the engine when it is not reqUired. The
switch will Isolate the cold start injector after approximately 8
to 12 seconds at -20°C (_4°F) decreasing this lime as the
engine approaches its normal operating temperature,
Although the cold start injector and thermotlme sWitch
operate independantly of the electronic control unit, an Input
to the E.C U. is taken from the starter motor
CIrCUlI.
This input
causes the E.C.U to slightly lengthen the time that the main
injectors are ·open· thus allOWing more fuel to be supplied to
the engine whenever the starter motor IS operated, This takes
place irrespective of the mlormation supplied to the E.C.U by
the other sensors or any operation 01 the cold start Injector
Maintenance of Fuel Injection System Components
Apart from attention to the fuel filters alter 80.000 km
(50 000 milesL the, remaining components of the fuel
injection system reqUire no routme maintenance.
2157
Fig. 9 Cold starting injector
2158
Fig. 11 Thermotime switch
9