nstallation of Cable
Select preferred location of choke knob inside vehicle, typical suitable places are:
a On the gearbox central tunnel adjacent to the driver's left knee (R.H. drive
vehicles). Route cable through air louvre passing out through front vent.
b Under steering column.
c On top of gearbox in front of gear shift lever passing through centre
console (fascia mounting).
Using the bracket as a template, mark out position of screw holes then drill 3.5mm /
0.1378" and secure bracket with self tapping screws.
Remove lock nut and washer from choke cable and feed cable through the bracket.
Thread the washer and nut over the cable and lock in position.
Run cable through engine bulkhead, it should be possible to utilise an existing grommet
although on most models a spare unused grommet exists. Care should be taken to ensure a
clear kink-free run from the bracket to the manual choke unit.
It may be necessary to trim inner/outer cable on final run to choke unit. A sharp pair of
wire cutters should be used.
Clamp the outer cable onto choke unit bracket with minimum protrusion through clip.
Run inner cable through nipple (L) and with choke knob pushed `fully in' clamp inner
cable to nipple.
F
unctional Checks
Reconnect battery earth lead.
Refit air cleaner if removed and check all vacuum hoses are re-connected.
Using sufficient choke compatible with ambient conditions, start the engine.
Set the fast idle speed to the manufacturers recommendation when the engine is warm.
Trouble Shooting
I
dentification of FASD Units
Isolated cases have been reported of incorrect FASD units being fitted in Service,
whilst they are identical externally, the vent fitted to each model differs internally.
They can be identified by a reference number stamped under the body casting on the side
furthest from the carburettor immediately below the blue plastic cover.
Specifications are as follows:
Vehicle Type
FASD Ref No.
BL Part No.
Rover 2000
4130
TZX 1005
Rover 2300
4132
TZX 1007
Rover 2600
4131
TZX 1006
Rover 3500
4027
AEU 2456
I
nitial Start Mixture Enrichment
During cranking from a cold start, additional fuel is required to compensate for that
which condenses out onto manifold and cylinder walls.
To achieve this a delay valve is incorporated in the adaptor block fitted between the
starter and carburettor allowing additional enrichment when closed.
The delay valve consists of a ball/seat operated through an electrically heated bimetal
strip.
On engine start, a separate drive module, housed in the instrument binnacle, supplies
current to the delay valve permitting valve opening after approximately 15 seconds.
Failure of either the drive module or delay valve will cause difficultly during starting.
D
rive Module Checks
Operation of the drive module can be checked as follows:
With the engine stationary and ignition switched off, connect a volt meter across the two
leads to the FASD delay valve on the carburettor. Switch on the ignition: there should be
no permanent voltage present, although a momentary pulse may be observed in some cases.
Start the engine, with the engine running (hot or cold), battery voltage should be present.
If not, the drive module or its wiring connections is/are suspect.
The drive module should be wired as follows: (Pin connectors are on base of module.)
Terminal:
1 Earth (Black wire)
2 Pulse (White/Black wires (2)
3 Power (Brown/Green wires (2)
4 Not used
5 FASD (White/Blue wire)
It is important to note that if either the module or the plug connector is removed from
the locating bracket; on refitting, the mounting lugs must be correctly engaged to avoid
the possibility of the leads or terminals fouling the base of the instrument binnacle.
D
elay Valve Checks
A moving coil or electronic ammeter should show a pulse when the ignition is switched on
and then remain at zero. Ensure pulse is in correct polarity direction, rectify if not.
The meter should indicate zero during cranking; if not zero then the vehicle electrics
are at fault.
The meter should indicate 4-6 amps after start for approximately 10 seconds and then
drop to typically 300 mA; if not, check that 12v is being applied to the delay valve
when running.
C
hecks to be made before removing starter
Check damper oil levels.
Without removing the blue cover check that the needle carrier is engaged and free to
move up and down, if disengaged change starter.
Check that the starter is held tight onto the carb and that the feed pipe joints are
secure.
Remove starter and delay valve.
C
hecks to be made after removing starter
Check function of carb non-return valve by drawing fuel out of the starter fuel feed
passage along a clean plastic tube. The fuel should not fall back when the suction is
ceased.
Connect 2 flying leads to the delay valve and blow into starter vacuum passage
(onto the white cross). Connect the leads to a 12v battery and note the time taken before
the valve opens by maintaining a constant pressure on the vacuum passage.
The time should be in the order of 15 seconds.
Check that the carburettor/starter vacuum passage is clear in the carb.
T
ypical symptoms and causes
Repeated fire, run, stall, when starting after a cold soak: delay valve open.
Remedy: change valve.
Piling after start: delay valve closed. Depression passage blocked.
Remedy: check circuit and change valve.
Starts but will not drive: carb dampers empty. Delay valve closed or depression circuit
blocked. Non-return valve not fitted to carb:
starter mis-set with no overtravel.
Extended cranking period:
faulty or dirty spark plugs or other electrical fault eg king lead off.
Feed pipe air leak or fuel circuit air leak.
Part warm restart problems: restart with throttle assistance may be required occasionally.
Engine speed increased after a few seconds running:
normal.
© RWP sept. 2003