Skoda Workshop Service and Repair Manuals > Octavia Mk1 > Drive unit | 1.8 ltr./92 kW Engine - Fuel Injection and Ignition System Motronic | Mixture preparation system, electronic inj.,Gas | Testing components and functions I

Testing idling speed

Note

t	The idling speed, ignition point and CO content cannot be adjusted.

t	The idling speed is checked during the basic setting of the engine.

t	The CO content is set to nominal value by the lambda control. Faults in the lambda control are detected by the self-diagnostic system and stored in the fault memory.

Special tools and workshop equipment required

t	Vehicle system tester -V.A.G 1552 - with cable -V.A.G 1551/3-

Test conditions

l	Exhaust system shut.

l	Coolant temperature at least 80°C.

l	Throttle valve in idling speed position → 1.8ltr./92kW Engine, Mechanics; Rep. Gr.20.

l	Disconnect electrical consumers (the radiator cooling fan must be off during this test).

l	Air conditioning switched off.

l	Do not connect up the pressure measuring device.

l	Selector lever in P or N.

Test sequence

–	Start engine and run in idle.

–	Interrogate the fault memory → Chapter. No fault must be stored, if necessary eliminate fault or erase fault memory → Chapter. Switch off engine and start again, conduct test drive and as a check once again interrogate fault memory.

–

Then:

t	Connect -V.A.G 1552-.

t	The engine must be idling for this step.

Readout on display:

–	Read measured value block (select function 08 and display group number 005 → Chapter).

Vehicle system test                 HELP

Enter address word XX

Readout on display:

–	Read off idling speed in display field 1.

Reading measured value block 5        ->

810/rpm   800/rpm   0.0 %        2.8 g/s

–	Press → key.

–	Enter 06 for the function “End output” and confirm the entry with key Q.

–	If the specified value is not achieved, interrogate once again the fault memory → Chapter.

If the idling speed is too high or too low and if there is no fault in the fault memory, perform the following inspections marked with points:

l	Check idling switch → Chapter.

l	Large unmetered air volume see → Chapter and read measured value block, display group 001, 005 or 008.

l	Inspecting throttle valve control unit → Chapter.

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