Skoda OCTAVIA 2004 Workshop Manual page 61

OCTAVIA
Display group 013, engine idling (engine warm, coolant temperature not less than +85 °C)
07.97
for models ä
♦ The fuel injection system features a smooth idling control. It is able to detect differences in performance between the
individual cylinders (parts tolerances, injector flow, compression, etc.) and to compensate for these by selective
metering of the quantity of fuel injected in the idling speed range.
♦ Such differences are detected in the idling speed range on the basis of the signal supplied by the engine speed
sender, which supplies four signals for each crankshaft revolution to the control unit. If the signals are received in the
same rhythm, all the cylinders are performing the same work. If one cylinder has a weaker performance, the crank-
shaft requires a longer time for the next half crankshaft revolution. In contrast, a cylinder with a stronger perform-
ance accelerates the crankshaft to such an extent that it requires a shorter time.
♦ If the control unit has detected a variation, the cylinder in question is immediately supplied with a greater or lesser
injected quantity until the engine is again running smoothly.
♦ What is shown in the measured value block is the variation of the injected quantity of the individual cylinders in
comparison to cylinder 3, which is necessary to achieve smooth engine idling.
♦ +... mg/H: The relevant cylinder has a weaker performance than cylinder 3 and is therefore supplied with more fuel.
♦ - ... mg/H: The relevant cylinder is stronger in performance than cylinder 3 and is therefore supplied with less fuel.
Read measured value block
0.82 mg/H -0.12 mg/H
Variation of injected quantity of cylinder 4 to cylinder 3
♦ -1.5 mg/H...+1.5 mg/H o.k.
♦ > +1.5 mg/H: cylinder 4 weak
♦ < -1.5 mg/H: cylinder 4 strong
Edition 12.00
S00.5111.54.20
Self-diagnosis
13
0.49 mg/H
Variation of injected quantity of cylinders 4, 2, 1 to cylinder 3
♦ -1.5 mg/H...+1.5 mg/H o.k.
♦ All display blocks are too large: cylinder 3 strong
♦ All display blocks are too small: cylinder 3 weak
Variation of injected quantity of cylinder 1 to cylinder 3
♦ -1.5 mg/H...+1.5 mg/H o.k.
♦ > +1.5 mg/H: cylinder 1 weak
♦ < -1.5 mg/H: cylinder 1 strong
Variation of injected quantity of cylinder 2 to cylinder 3
♦ -1.5 mg/H...+1.5 mg/H o.k.
♦ > +1.5 mg/H: cylinder 2 weak
♦ < -1.5 mg/H: cylinder 2 strong
K Readout in display
No readout
01
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