Dacia Solenza (engine E7J). Manual - part 27

IGNITION AND INJECTION

17 - 14

The engines equipped with UCE injection type SIRIUS 32 are provided with oxygen sensors, as

follows:

- one upstream oxygen sensor – for engines corresponding to EURO 96 de-pollution norms.
- one upstream oxygen sensor and one downstream oxygen sensor – for engines corresponding

to EURO 2000 de-pollution norms.

OXYGEN SENSORS HEATING

Oxygen sensors heating control is given by UCE injection as follows:

- for upstream oxygen sensor – starting with engine starting.
- for downstream oxygen sensor – after a certain time from engine starting, imposed by the

UCE injection charts, being subject to engine RPM and water temperature, red only when the
acceleration pedal is not released.

UPSTREAM OXYGEN SENSOR VOLTAGE

After connecting the CLIP tester select “ Injection Diagnostic” and refer to “PR009 parameter:

Upstream oxygen sensor voltage”. The displayed value, expressed in mV, is representing the voltage
supplied towards UCE injection by the oxygen sensor placed upstream as the catalyst. When the
engine is running in the “closed loop” phase, voltage must fluctuate quickly between the following
limits:

- 20 mV ± 50 for poor fuel mixture;
- 840 mV ± 70 for rich fuel mixture.

Smaller is the difference between these two limits, less good the sensor information is

(generally this difference is of 500 mV).

DOWNSTREAM OXYGEN SENSOR VOLTAGE

After connecting the CLIP tester select “ Injection Diagnostic” and refer to “PR010 param-

eter: Downstream oxygen sensor voltage”. The displayed value, expressed in mV, is representing
the voltage supplied towards UCE injection by the oxygen sensor placed after the catalyst. This
sensor has the purpose to catalyst diagnostic and to perform a second checking, more exactly, of
the fuel mixture enriching. This function is becoming active only after a certain time of engine
running at warm and it is not active in the engine idling phase.

When the engine is running in “closed loop” phase and at stabilized speed, voltage must fluctuate

having between the maximal and minimal limits a difference of 600-mV ± 100. At deceleration,
voltage must be under 200 mV.

Enriching adjustment

IGNITION AND INJECTION

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

IGNITION AND INJECTION

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PRINCIPLE

When the engine is in “closed loop” phase, the enriching adjustment is correcting the injection

time in order to be able to obtain a fuel mixture with the enriching as close as possible to 1. The
correction value is fluctuating around the value 128, within the limits 0 and 255.

Although, variations in time of the components elements parameter of the injection system may

occur, this leading to the enriching correction displacement towards 0 or 255, in order to maintain
the enrichment at the value 1.

The adaptive correction is allowing the “resetting” of the injection chart in order to bring the

enrichment adjustment to the average value 128 and the achievement of an effective constant
correction for the enrichment or impoverishment of the fuel mixture.

The adaptive correction of the enrichment adjustment is divided into two components:

- preponderant adaptive correction at engine medium or high charges (adaptive enriching

during running);

- preponderant adaptive correction at engine idling or small charges (adaptive enriching

during idling).

The adaptive corrections are considering the value 128 as an average value after performing

the activation (after erasing the memorized failures) and they have for the next parameters, the
following limit values:

PR030 = Adaptive enriching during running 80< X < 176
PR031 = Adaptive correction during idling 80 < X < 176.

The adaptive corrections are not applied unless the engine is warm (water temperature > 80°C),

and it is in the “closed loop” phase and the pressure from the inlet manifold is in a certain interval.
It is necessary that engine has been run in “closed loop” phase in many of the inlet manifold
pressure areas, for which the adaptive correction evolution is starting the compensation of the
engine running enriching dispersions.

Therefore, further to UCE injection re-activation, after erasing the memorized failures, when

the values PR030 and PR031 are 128, it will be necessary that a specific road test is to be per-
formed.

Enriching adaptive correction

IGNITION AND INJECTION

17 - 17

ROAD TEST

Test performing conditions:

- warm engine ( water temperature > 80°C);
- engine RPM not exceeding 4000 rot/min.

For this test, it is recommended starting from a sufficient low engine RPM, in gearbox third or

fourth gear, accelerating then progressively in order to obtain a pressure stability in the inlet (PR001
= inlet manifold pressure) for 10 seconds in each area, as per next table:

Enriching adaptive correction

Area 1

Area 2

Area 3

Area 4

Area 5

(mbar)

250-------------- 399 ---------------- 517 ----------------- 635 ----------------- 735 -------------- 873

Average 325

Average 458

Average 576

Average 694

Average 813

After performing this test, the corrections will become effective.

PR031 parameter (adaptive enriching at idling) is more fluctuating in the idling and small charges

phases, and PR030 parameter (adaptive enriching during running) is more fluctuating in the mo-
ment of medium and full charges, but both parameters are active in all areas of inlet manifold
pressure evolution.

It is necessary that road test to be followed by a normal driving running, constant and fluctuate,

on a 5-10 Km.

After test performing, connect the CLIP tester and refer to the values of PR030 and PR031

parameters. If their values are initially at 128, after correct performing the road test, they must
change. Contrary, perform again the road test, strictly observing the imposed conditions.

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