Learning Procedure; Engine Idle Speed Check; Checking Concentratio Of Pollutant Emissions; Checking Idle Co And Hc Concentration Upstream Of The Catalytic Silencer - Fiat Bravo Service Manual

Engine
Fuel system
10.

Learning procedure

NOTE During the /earning procedure, from the moment the ignition is turned to the ON position until the
end of the procedure, do not press the accelerator pedal, the brake pedal or the clutch pedal.
Manual learning:
- Turn the ignition key to the ON position.
- Wait for 60 seconds; during this period the return spring inside the butterfly casing and the maxi-
mum/minimum angular positions of the motorized butterfly valve are checked.
- Turn the ignition key to the OFF position.
- Wait for 10 seconds; during this period the values acquired are recordd in the control unit EEPROM.
Learning with diagnostic equipment signal "learning ended with positive outcome".
- Connect the diagnostic equipment.
- Place the ignition key in the ON position.
- Wait until the diagnostic equipment gives the positive learning outcome signal.
- Turn the ignition key to the OFF position.
- Wait until the diagnostic equipment signals that the procedure is over.

ENGINE IDLE SPEED CHECK

If the engine idle speed is not 750±50 rpm and the injection/ignition control unit is the self-regulating
type, then it is not possible to carry out any adjustments, therefore it is necessary to check that the accel-
erator linkage is correctly adjusted and the cause of the problem should be sought by carrying out a com-
plete fault diagnosis using the diagnostic equipment.
CHECKING CONCENTRATION OF POLLUTANT EMISSIONS
Through the self-adjusment of the system, the Motronic ME 3.1 system guarantees a continuous check on
the idle speed and CO percentage, thereby making any outside adjustment operations superfluous (there
are no adjustment screws). However, a check on the content of the exhaust gases, downstream fo the
catalyzer, can provide precious information on the operating conditions of the injection/ignition system,
the engine parameters or the catalyzer.

Checking idle CO and HC concentration upstream of the catalytic silencer

To check the concentration of carbon monoxide (CO) and unburnt hydrocarbons (HC) upstream of the
catalyzer, proceed as follows:
1. Undo the cap or nut on the exhaust pipe, upstream of the catalyzer and tighten the tool in its place.
2. Connect a suitably calibrated CO tester probe to the tool.
3. Start up the engine and let it reach operating temperature.
4. Check that the speed corresponds to the recommended figure.
5. Check that the idle CO concentration is within the recommended figures given in the table overleaf; if
this is not the case, it is necessary to check:
- that the Lambda sensor is working properly, using the diagnostic equipment;
- for the presence of air penetration in the area surrounding the Lambda sensor housing;
- the injection and ignition system
6. In the same conditions, check that the concentration of HC is below 600 p.p.m.
7. If these values are not measured, check the engine tuning, paying particular attention to:
the ignition advance value - the valve clearances - the valve gear timing - the engine compression.
3 8
( in particular, the wear of the spark plugs).
Bravo- Brava 9
98 range
Print n° 506.670/20