Dacia Solenza 2004, Repair Manual

Page: 109 / 891

IGNITION AND INJECTION
17
17 - 15
ENRICHING C ORRECTION
After connecting the CLIP tester, select “Injection diagnostic” and refer to “PR035 parameter:
Enriching correction value”. The value displayed is representing the corrections average imposed
by the UCE injection, subject to the fuel mixture enriching, red by the upstream oxygen sensor (the
sensor is analyzing the oxygen concentration from the exhaust gases).
The correction value has an average value of 128 and the limits are 0 and 255:
- a value lower than 128 has as result, the request for fuel mixture impoverishment
- a value greater than 128 have as results the request for fuel mixture enriching.
ENRICHING ADJUSTMENT PHASE
Admission in the enriching adjustment phase is becoming effective after a certain time from
engine starting, with the condition that water temperature is reaching to over 22°C and 28 seconds
from engine starting have passed.
If admission in the enriching adjustment phase is not effective, the value of PR035 parameter is
128.
Even when conditions for enriching adjustment phase beginning are accomplished, UCE injec-
tion however, will not take into account the voltage supplied by the downstream oxygen sensor, in
the following situations:
- acceleration pedal fully pressed: PR035 is variable and higher than 128;
- sudden acceleration: PR035 is variable and higher than 128;
- deceleration (engine braking) followed by UCE injection detection of the position ”free” of
the acceleration pedal: PR035 = 128;
- downstream oxygen sensor failure: PR035 = 128.
WORKING PROCEDURE “DAMAGED” IN CASE OF DOWNSTREAM
OXYGEN SENSOR FAILURE
When the voltage supplied towards UCE injection by the downstream oxygen sensor is not
correct (showing small or not at all variations) in the enriching adjustment phase, then UCE injec-
tion will not pass to the working procedure “damaged” (PR035 = 128) unless the failure has been
recognized as being present for 10 seconds. Only in these conditions, the failure will be memorized
by the UCE injection.
If UCE injection is detecting a present failure of the oxygen sensor and if this failure has been
already memorized, then UCE injection will come out from the enriching adjustment phase, passing
to phase “open loop”. In this situation PR035 parameter will not show variations and will have the
value 128.
Enriching adjustment
vnx.su