Fiat 1996 Brava Service Manual page 45

Bravo-Brava
Introduction
Planned maintenance
oo.
If the values are not within the limits set out in the government circular, the Customer must be notified of
the need to check:
- that the Lambda sensor is working properly using the Fiat/Lancia tester;
- for the presence of air penetration in the area surrounding the Lambda sensor housing;
- the injection system, particularly the wear of the spark plugs.
2. If the HC figure is more than 90 p.p.m., the cause of the problem should be sought in the engine tim­
ing or the decreased efficiency of the catalyzer.
VOLT
i
mV
1000-
8 0 0 -
6 0 0 -
4 0 0 -
2 0 0 -
0 -
^
GE
0 070 »
, U,Sf U ^
RICH I
MIXTURES T
■ i * — 1 1 030
LEAN
MIXTURES
I'
0,7 0,8 0,9 1,0 1,1 1,2 1,3
AIR COEFFICIENT X
Factor X is obtained from the ratio between
the quantity of intake air and the theoretical
quantity of air required to burn all the fuel in­
jected.
To achieve an optimum mixture the quantity
of fuel injected must be as close as possible
to the theoretical quantity required to be
completely burnt in relation to the quantity of
air drawn in by the engine. In this case the
Lambda factor is equal to 1 (ideal mixture)
and the CO content is within the legal limits.
With X ^ 1 (lean mixture), excess air, the CO
tends to assume low values: with X ^ 1 (rich
mixture), lack of air, the CO values tend to be
high.
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