Fiat 1996 Brava Service Manual page 330

Engine
Fuel system
10.
When measuring the distance, it is vital
to be at right angles to the flywheel
and corresponding to a tooth and not a
gap.
Bravo 101 20v
98 range
Checking the gap
The rpm and TDC sensor is fixed directly to
the cylinder block/crankcase and therefore
the gap and the angular position do not need
adjusting. If a fault is suspected, the gap can
be checked as follows:
- remove the rpm and TDC sensor;
- check that the distance between the sur­
face of the sensor and the flywheel tooth
corresponds to the total length of the sen­
sor probe (34.5mm) with the gap (0.8 -1.5
mm).
l
* *
M22P
i
-i_r
I/I54
M38 M6
DETONATION SENSORS (0.261.231.131)
The detonation sensors are located in the
monobloc under the inlet manifolds and be­
tween cylinders 1 -2 and 4-5, respectively.
These sensors have a bush to prevent inap­
propriate torque tightening.
If they are replaced, do not place washers
or shims between the cylinder block-
/crankcase and sensor contact surfaces.
When the engine is knocking (detonation),
vibrations of a certain frequency are pro­
duced in the cylinder block/crankcase.
This phenomenon produces a mechanical
ripercussion on a piezoelectric crystal which
sends a signal to the control unit which, on
the basis of this signal, reduces the ignition
advance (by 3° up to a maximum of 9.7°) un­
til the phenomenon disappears. Later, the
advance is gradually restored to the basic val­
ue.
Wiring connector
The sensors are connected to the electronic
control unit (Pins M22/M54 and M38/M6)
by twisted cables covered in an anti-interfer­
ence outer casing.
The numbers indicate the corresponding
control unit pins.
24
Print no. 506.670/76