Fuel,
Emission and Exhaust System
D:04:01
EMISSION CONTROL SYSTEM
CO EMMISSION ADJUSTMENT
IDLING*
SPEED
R.P.M.
950*
T
CO
%
ON EACH
BANK
1%
1
1
MAX
IMBALANCE
PERMITTED
±0.3%
i
'(Setting
idle only. Normal Engine R.P.M. 775 r 50
R.P.M.)
The idle mixture adjustment must be sealed to
comply with Federal Regulations. The idle
mixture is set at the factory and is unlikely to
require further adjustment throughout the life
of the vehicle. If any malfunction in vehicle
performance is noted it is essential to ensure
that all other engine settings are checked prior
to attempting the adjusting of the idle mixture.
The engine must be run in with air filter in position.
The ignition system must be serviceable and
correctly set. No
air
leaks must be present (Brake
Vacuum Hose, Ignition Advance Capsule Pipe,
Fuel Lines, Oil Vapour Rebreathing Pipes etc).
An
infra
red exhaust gas analyser must be used for
this adjustment. Each exhaust down-pipe has a
boss fitted
with
a plug which may be removed for
fitting the exhaust analyser pipe in its place.
Exhaust gas analyser comprises of two metal pipes
which screw
into
each plug hold A3-way union
joined together on one hand by the hoses to the
metal pipes and on the other hand to the analyser.
The connection to the analyser must be air tight.
1.
Plug in diagnostic plug and connect up rev
counter to check engine R.P.M.
2.
Switch Dwell operation for 6 cylinder engine.
3. Disconnect the electrical connection to the
oxygen (lambda) sensor.
4.
Ensure that the idle speed screw (1) common
to both banks is fully closed.
Note:
DO NOT adjust the two individual bank by-
pass screws as they are set at the engine
manufacture plant.
5. Ensure that the air conditioning system is
switched off.
6. Fit a link wire to the cooling fan switch to
ensure the cooling fans are on continuously.
7.
Stan
the engine and run it until it has reached
normal working temperature
lie.
cooling
system thermostat open
—water
pipes hot).
8. Check that the engine speed is 775
=
50 RPM
and running smoothly.
9. Check ignition timing
is
13° ± 2° at
775.RPM
and adjust if necessary. Rev the engine to 2000
RPM and check that the timing
is
about 40°
B.T.D.C.
10.
Using
idle
speed screw common to both
banks, adjust the idle speed to 950 RPM
(temporary setting).
11.
Check Dwell operation for duty cycle is 50%
*
3.0%.
12.
To ensure that plugs are not "sooted" due to
long idling, rev engine at 2000 RPM for 15
sees
and start the next
operation
immediately
afterwards.
13.
With both taps on the T-piece of the sample
hose open, and the plastic cap or fingertip
blocking the hole for fuel adjustment, check
that the idle CO level is 1% ± 0.3%.
If not reset the fuel by removing the plastic cap
or finger tip and turning the mixture screw (2)
in the flap valve clockwise to increase the CO
(richer) and anti-clockwise to reduce CO
(leaner). Replace the plastic bung, reset the
engine speed to 950 RPM rev the engine for a
few seconds to 2000 RPM and check CO level
when idle speed returns to 950 RPM. If outside
the limits repeat the procedure until
specification is met. Fig. 19.
&Wy
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