Citroen c4 Picasso 2.0 HDI: Engine Operation Issues in Cold Weather After Afterburning

mlodyck wrote:

I was also wondering that if it is -20 outside, the pressure on the slat decreases - it is difficult to fire. If I leave the car at such a temperature for several days, after which the temperature rises to -10, the engine starts the first time, the only thing left is the casting symptom for a few seconds. Would it be the fault of the pressure in such a situation? After all, the engine would have to rotate a few times, maybe even a dozen or so, to pump the fuel.

How do you check the fuel pressure in the tank? If, with the help of an external diagnoscope, you can, besides pressure, see many other parameters, including all of them temperatures during the morning start up. Which should be equal window thermometer (table below, lines 19-21).

One of the most important sensors deciding about quick start is :

- Coolant temperature sensor . If it is freezing outside at -20 degrees C., and the coolant temperature sensor is cheating and indicates, for example, +80 degrees, the computer will give a "small" starting fuel dose for the injectors instead of a "high". The engine will not start the first time, only after repeatedly turning the starter, as the computer automatically increases the boot dose.

I emphasize with emphasis what is happening despite the impeccable condition of the high pressure pump (pwc), control valves, injectors and the entire starting circuit . The computer does not display any error, because the sensor falls into the so-called "measuring goodness", i.e. indicates within acceptable limits.

A characteristic signal that the defect is on the coolant sensor side is no heating of glow plugs . Everyone gets to them, and in the meantime they will not turn on despite the frost -20 degrees, because the temperature sensor erroneously indicates +80 degrees. Therefore, it is logical that with an allegedly hot engine, the computer will never turn on the heating of candles in life.

The engine will also run unevenly after ignition until the sensor temperature equals the actual liquid temperature. The reason is, as I mentioned, a disproportionately small dose of fuel in relation to current needs.

The principle is simple. If the engine is cold - it needs "a lot" of fuel. If warm - "not enough". The dose of fuel injection is directly controlled by a computer based on the so-called. injection molds, although all components of the injection system work without reservations. One temperature sensor is to blame, which for some reason distorts the electrical signal (from 0.2 down 4.8 V. ) reaching the control computer.

This is a failure of the so-called sensor, often underestimated in diagnostics, because all it seems that when the engine burns badly, some terrible things must happen with the injectors, pwc, etc. Meanwhile, in most cases, the cause may be a very loose cable on the sensor or flooding with some liquid.

The simplest test is to switch off the sensor electrical connector and then try to start the engine. As far as my memory is correct, in 2.0 HDI DW10BTED in Picasso the computer then uses an emergency replacement temperature of -50 degrees C or "last good measurement". See table below, row 19. Warning! It shows the specifications of the 1.6 HDI engine, so they may vary in detail from your power unit.


If the drive unit lights up immediately from the first time, and when the sensor is turned on, it does not want and works evenly at idle - it indicates a defect of the sensor, more often its cables and contacts.

Usually this happens on the side of the damaged cables and contacts, and not on the sensor itself. Which cannot burn because it is not electrically powered (2-pin sensor) or only 5V (3-pin sensor). It also cannot break down mechanically because there are no moving parts.

You should carefully check whether the sensor is flooded with any liquid, e.g. fuel, oil, water, etc. It may then temporarily distort the resistance, which is a measure of the temperature value for the computer according to Ohm's law. All you have to do is just dry the sensor connector and the problem of starting in cold weather disappears.

I will discuss the remaining parameters if the mentioned coolant sensor turns out to be impeccable. And of course, if you wish me to continue ...

Look at a similar topic https://www.elektroda.pl/rtvforum/topic3215000.html

Kitten KotBury2

Quote:

with this engine and I know from experience that these are often injectors, but it is worth pouring something into their fuel into the fuel and see if it helps.

Exactly for this Delphi fuel system 2T oil is recommended and the fuel filter needs to be changed on time, because delphi has too delicate systems and a small amount of air in the fuel system is enough by gradually clogging the fuel filter, where then such a pump produces chips, because so far, I did not notice in people who actually care and replace the fuel filter on time.
However, it rarely happens that there are guilty contacts on the ankle, because usually no contacts, it automatically pops up the error of a certain sensor, which is missing the contact of the installation on the ankle.
However, starting problems are associated with several reasons: The temperature sensor distorts the value (if the contacts are missing, this will show the sensor error), the fuel dose control valve sticks (if the chips are present, the valve may be so dirty that the fuel dosage is poor) , weak battery (checking the module), damaged injection (which is most often manifested in uneven engine operation and difficulty in starting the engine), glow plug (the last of the possible version, but it is common that only one candle is functional or all does not work.).

So the question remains:
Do you not feel as if the battery is too weak during startup?
Are there a problem above zeros plus or only during more severe frost?
Does the problem of uneven engine operation also occur after the engine has warmed up?

Quote:

Battery - although charged, it didn't want to start, it behaved as if it was getting fuel, caught and did not start.
Trnsit2- the problem of uneven engine operation is noticeable at 0 degrees and less, and only for a while after firing, then the engine runs smoothly. What do you mean by writing a battery - check the module - which module?

I meant the "EcoMode" module, which is often a Citroen affliction.

Transit 2 wrote:

Quote:

with this engine and I know from experience that these are often injectors, but it is worth pouring something into their fuel into the fuel and see if it helps.

Exactly 2T oil is recommended for this Delphi fuel system and the fuel filter needs to be changed on time, because delphi has delicate systems.

Why do professional mechanics give conflicting, moronic advice? Why pour "something to clean" and then 2T oil for lubrication? If metal filings are released as a result of "dry" fuel, how does this cleaning material dissolve metal chips?

A general tip that you should remember for the rest of your life is that when it comes to diesel engines with an injection system Common Rail , this never pour cleaning agents into the fuel. Because they contribute to an even greater "drying" of the fuel than it was in accordance with the applicable standard since 2006. From that date, sulfur was removed from crude oil as part of the so-called environmental protection.

Probably every child in kindergarten already knows what effects are caused by pouring denatured alcohol, gasoline, spirit, solvent or acid into diesel fuel? Everyone knows, except for professional mechanics ...

Such advice should be immediately punished by admins because they are there dangerous to users and their turbodiesel rather than alleged faulty battery voltage values. No one has ever hurt anyone about the battery voltage. But immediately it is captured and circled in red by Admin.

However, the most harmful suggestion is to pour some solvent into ON in order to remove impurities or deposits from the injection system. However, Admins are silent on this subject. Drivers accept advice for a good coin, because it is given by a professional mechanic. Then pour in thoughtlessly various STP, Xeramizers, Skyddy, or other strong solvents, contributing to the dangerous phenomenon of seizure, jamming of high pressure pumps due to too "dry" fuel.

It is really a shame and embarrassment that indifference and dilettante are tolerated in such a wide forum. Which should be a model of professionalism, not crony just because a professional mechanic writes something.

Kitten KotBury2

Quote:

A general tip that you should remember for the rest of your life is that when it comes to diesel engines with the Common Rail injection system, DO NOT PURIFY ANY CLEANING AGENTS. Because they contribute to an even greater "drying" of the fuel than it was in accordance with the applicable standard since 2006. When it was obligatorily removed sulfur from crude oil.

It is good that you did not express yourself with HDI, but only the "Common Rail" system, but to the point: The quality of fuel due to sulfur removal does not cause filings, this time. (Do not duplicate the one that is not proven, because I have not noticed those who really care.)

On the other hand, often the formation of swarf is caused not by dry fuel, but only by the neglect of the fuel system, for example, not at the time of fuel change, the fuel system leaks, which initially causes the fuel to flow back into the fuel tank. (common cases)
As for cleaning products, they are of a newer generation, where such a product not only cleans, but also lubricates, so there is no ordinary cleaning agent as mentioned above by a colleague: "denatured, gasoline, spirit, solvent, or acid? "(The fact that the measure was not immediately explained.)

Quote:

If metal filings are released as a result of "dry" fuel,

If the high pressure pump is already giving off swarf, then nothing saves like removing the injectors and putting in for cleaning, (for clarification here a colleague, cleaning the injectors by dismantling and reassembling them on the table, but not in home conditions, or even a regular garage.), also putting the injection pump into regeneration.

Quote:

fuel dose 7.20 mg / stroke
injector correction1 67%
injector correction2 95%
injector correction3 144%
injector correction4 92%

If it does not yet give off filings, then it is worth using 2T oil, because it happens that after this procedure it helps, of course, as long as the fuel system is tight, except that you should not stop adding 2T oil.

Pzdr. Transit 2

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How to check the economy module?

You can check the battery condition when starting the engine (when you have difficulty starting), and possibly try to enter the capacity of the battery into the computer, provided that the battery is fully functional.
At my suspicion, the battery had to be changed before, which resulted in the computer having previously memorized the battery damage and the computer does not know whether the battery was changed or the computer detected a weak battery capacity, i.e. not enough amps, on which it does not allow the engine to start during a higher battery load , and this is in order not to completely discharge the battery. (I think that's a problem here.)

However, when it comes to injectors, one has a visible difference, but it's worth adding 2T oil to the very beginning.