Checking engine idle speed

CHECKING ENGINE IDLE SPEED

If engine speed is not 850 ± 50 rpm, because the injection-ignition system is self-regulating, no adjustment can be carried out. It is therefore necessary to check that the accelerator linkage is properly adjusted and then search for the fault through full diagnosis using a Fiat/Lancia Tester.

CHECKING LEVELS OF POLLUTING EMISSIONS

The IAW - 1 AF.13 system is self-adaptive and thus constantly monitors idle speed and CO levels. Therefore there is no need for manual adjustment (adjustment screws are no longer fitted). However, checking exhaust contents downstream of the catalytic converter can provide useful information about the injection-ignition system condition, engine and catalytic converter parameters

Checking CO and HC levels when idling

Measure levels of carbon monoxide (CO) and unburnt hydrocarbons (HC) with the catalytic converter hot (300 - 350 °C) (it is advisable to push the car engine on the road for about 5-10 minutes to ensure that the catalytic converter reaches service temperature), Then fit the probe of a suitably calibrated tester to at least 30 cm as indicated in the figure.

If the shape of the exhaust tail pape will not allow the probe to be fully inserted, add an extension pipe designed to ensure a seal in the joint area.

1. Check that CO and HC levels are as specified in the table;
2. If CO level is not as specified, check that:
   • Lambda probe is working properly, with the aid of a Fiat/Lancia Tester;
   • for air leaks in the area surrounding the lambda probe seat
   • the injection and ignition system (particularly for spark plug wear).
3. If HC level is not as specified, the engine is not properly tuned or the catalytic converter is not efficient.

Summary table showing emission level tolerances downstream of converter