Megane 1.5Dci Injection Fault

[4tesq]

Hi everyone, hopefully someone can help me with the subject issue once and for all.

Apologies if I have added to the huge amount of posts regarding this problem but it seems to me like everyone has different scenarios so hopefully mine might be solvable because at the moment I am ready to set fire to the car.

So, the issue started driving along as normal down the motorway in fifth gear and when accellerating I got a beep, injection fault on the display and the STOP light appearing. This lasted a few seconds and then went away. No loss of power or smoke from the exhaust.

This carried on for a while, gradually getting worse.

Next thing to happen was when trying to start it in the morning it took a few attempts to get going and the same injection fault message appeared on the display. Eventually the car started and ran fine although the injection fault appears again when under hard accelleration as before.

As i started to investigate this fault online I found it could be a number of causes but one of which being air in the fuel line and so after speaking to a few mechanical friends and researching online I found that using a non genuine fuel filter could be to blame and so first thing was to replace the fuel filter with one from Renault (the one on the car had been fitted by the previous owner)

After replacing the filter I primed the system fully as you should and after 2 attempts the car started. Brilliant, problem solved I though. Let it run for a while as I put bits and pieces back together and then as a final test, turn engine off and back on again.

Car wouldnt start and injection fault on the dash.

After some time the battery went flat and so after hooking it up to a friends car the starter motor was smoking and so we decided to leave it.

Plugged a computer in and got the below fault code.

DF772 - Pressure control parameter at maximum stop

I consulted another mechanical friend (who breaks Renault's) who said it is more than likely the fuel rail pressure sensor (the one that connected into the "spider" looking piece which splits the fuel to the 4 injectors. He had one off another 1.5 Renault he was breaking and so I managed to get the car started (using easy start) and went to replace the part

Replaced the whole "spider" piece along with sensor and rebuilt, tried to start the car but by now the starter motor was completely FUBAR

New starter motor purchased and fitted, tried to start car and eventually got it going but still with injection fault.

Must be one of the injectors and so with car running unplugged them one at a time to see if it made any difference to the engine. Out of 4 injectors, 3 of them changed the way the engine ran when unplugged and so decided that the fourth one (which didnt make even the tinyest different wen unplugged) must be at fault.

Replaced the injector, coded with the computer and tried to start again.

And yet again, after a few attempts the car starts but shows injection fault and also does the same when putting the engine under pressure during driving.

Plugged the computer in again and still the same fault (cleared codes and re-tried)

DF772 - Pressure control parameter at maximum stop

So to sum up, parts replaced are;

Fuel filter
Fuel Rail Pressure Sensor (and spider splitter)
Injector
Starter Motor (not that this is anything to do with the injection system)

I checked the old filter for metal filings with a magnet and there were none to be found.

Does anyone have any clue as to what I should do next. I have next to no money and so doing the work myself (with assistance from mechanic friends) so cant afford brand new parts or expensive diagnostics let alone a new car!

Please someone help, I am currently stranded 50 miles from home at my mothers house and just want to get it fixed and back to normal

[460316DSG1]

Hi. Does the fault come up if you drive at normal speeds and don't put your foot down hard or when you are changing up to the next gear again without putting your foot down! if it doesn't it could be the following:

I owned a Citroen Diesel which worked fine until I put my foot down changing gear or just passing a car. When you put your foot down the Turbo has to push more air into the engine and to do this there is a "Solenoid" that creates a vacuum from the engine to the Turbo (to open a part in the Turbo) and it could be this that is either Sticking or a air/vacuum leak between it and the Turbo or engine.

On my car it was the solenoid sticking, got it replaced and the problem went away.

I am not saying it is this part but it's worth a look.

Hope this helps.

460316DSG1

[craigyt]

Iv recently had this same problem. I cleaned the map sensor with carb cleaner, took the egr valve off completely and cleaned every part of it, and then also the crankcase breather that goes to the inlet pipe from airbox to turbo i opened that up and cleaned that as that was all clogged up and not allowing it to breathe.

Car now runs like a dream at 65mpg!

[4tesq]

Thanks for the replies

I do not think it is anything to do with the turbo because of the issue with starting and the turbo does not kick unless over about 2500 revs.

Today I have removed the EGR valve and cleared it out, not with carb cleaner but just cleared the muck out.

Where is the map sensor?

[craigyt]

Its in the black plastic pipe that comes from under the battery then clamps to the egr housing, unplug it the pull the clips back to get it out

[4tesq]

Another update. I have removed the fuel pressure regulator that is attached to the fuel pump (brown connector) Given it a clean up (and also a few taps with the end of a screwdriver)

Rebuilt and the car started, although a bit lumpy (this is more than likely due to the fact I had removed all the fuel lines to get to the sensor and so the system had air in it which it needed to clear)

Turned the engine off a couple of times and started first time each time.

Went for a drive to put some fuel in, all ok on the way there but after putting some fuel in had injection fault on startup and it took a few attempts. So back to square one.

Would you take this as having a fault with the regulator?

[craigyt]

A proper diagnostics session would be the way to go, they can take readings from sensors to see if they are reading correctly or not. The aa was goin to do it on mine but the car wouldnt even try starting but if yours cranks over then fires readings can be taken

[AlexB]

You need to plot the engine parameters while replicating the fault, then compare them to a healthy engine. This can be done with a cheap OBD interface connected either to a laptop or Android phone.

It is strange that the engine is having problems starting while complaining about high rail pressure. It can be the pressure sensor or the injectors blocked by the filings from the failing pump...

[4tesq]

And another update



I have been to see a Renualt specialist who charged me £20 to look at the fault codes and live data.

The pressure on starting the engine was way down at 80bar and he said it should be around 300bar.



He believed the issue to be an injector and so pulled the return pipes off them all and watched as the engine was cranked.



This showed that the injector to the far right (number 1) was just pumping fuel straight back out. All the rest were just tiny dribbles.



So, got hold of an injector and have replaced it. Now the car starts first time but does show "check injection" on the dashboard.



I believe this is just because I need to get the new injector coded and so am now waiting for a friend to appear with his computer and then hopefully all will be solved!

[AlexB]

How would the car know that the injector is not coded in? "Check Injection" is on either because a fault needs to be reset or because some parameter (e.g. rail pressure) is not normal. Furthermore, you wrote before that the code was "Pressure control parameter at maximum", but it is below minimum now... Ah, they probably meant that the control input was set to maximum in order to rise the pressure which was too low! It makes sense. In this case the problem is one or several injectors leaking too much, thus causing low rail pressure. There is a leak test for testing injectors - read the manual in the sticky thread. Air entering the fuel system may cause the same thing - low rail pressure. So, check the clear pipe to the HP pump for bubbles of air.

[kentmegane]

H there
I have a Renault Megane 1.5 dCi 100 and had the same problems as you.
Injection fault coming up mostly with 4th and 5th ... and some times on 3th ... and only when I was flooring it.
No problems at all when driving normal.
Also when I tried to start the car when already warm it would not start on the first turn ... and sometimes injection fault might come up.

I scanned the fault codes with my OBDII scanner although not CLIP still showed that the regulator was at fault etc....

I took the car to a Renault Specialist and explained all the problems, his first suggestion was to check the injectors for the return fuel and also .. check the quality of the fuel.
The results showed that the qualty of the fuel was good and there was no problem to worry about the pump etc.
But the No1 injector the one next to the battery (same as the one you stated) needed to be changed as it was hardly using any fuel.

I ordered a recondition unit, and just took it today to the garage to replace it and code it in.
They replaced it and the car drives way more powerful!
When the reconditioned injector came it had the code for the garage to code it in the car's ECU.
If it is not coded in properly it will not spray the correct amount from what I am given to understand. (to be honest the garage that replaced your injector should have coded it in, it only takes a couple of minutes to do so).

Hope everything works for you. They are great engines

[4tesq]

Hi All, I am doing all this work myself as cannot afford a garage and so am using friends computers to read codes and input data

Anyway, I have another update.

Went to code the new injector put into cylider 1 and the ECU threw a fit, would not accept the new code. The computer said the operation was successful but when starting the car after coding it showed "check injection" and would not let you rev the engine at all.

Using the computer to look at the codes, the ECU had not taken the code that we typed in and instead had entered a load of numbers.

Numerous tries including disconnecting the battery for a while did not help and so I got the code from my old injector, entered that and got the car back to the point of starting first time but showing "check injection" and running lumpy.

After speaking to my Renault friend he said that there are two types of injectors and the one I have fitted is obviously the wrong type as the ECU will not accept the code.

So I am now waiting for another injector to arrive to try again!

[tomalamix]

hy there...ive got a 100cv dci. so far many things happen with the almost 400.000Km on it...

concerning your problem ive had a problem with the same symptoms as you, in the end it was the HP Pump...there is no EOBD cable to detect the fault on the pump, forget about it if the problem is in the pump it self.

for start do you know the right ordering no. of the injectors in the engine? are you coding the injectors correctly? im asking this because if you fail to code an injector the dash displays "check injecton" and no rev up is possible.

injector No.1 is the one near the battery..is this what your doing?

If youre doing it and the car doesnt accept the code is because that injector is not for your engine. the injectors are equal outside but only there is a few ranges of injectors for the K9K engines, and from those only a few works on specifics engines.

whats the "EJBR..." code written on the injector? and whats your engine code or BHP?

post back results...

[James46322]

I currently own a renault megane estate 54 plate 1.5dci with check injection constantly showing i took it to renault and the pulled up a fault which was to do with injector 4 will changing it cure the issue completely i also have a warning light which says the word service. The car is also a pain to start on a cold morning and bellows blueish smoke causing a smoke screen everywhere but is fine as soon as the engines warm could this relate to needing a new injector? Could anyone with any help please private message me aswell thanks

[DarekW]

Hi Guys,

Same problem in my Megane II PHI 1.5DCi 82hp 230kkm. Engine in very good condition but for a year I have a problem with injection fault.
A year ago repaired all four injectors (2 two were leaking a bit) but still shows injection fault while overtaking or just speeding up. Few months ago it happened on 4th and 5th gear but right now also on 2nd and 3rd. It shows DF772 error. Both of them appear when checking errors:
DF 722 - Pressure Control; parameter at the maximum stop
DF 722 - Pressure Control; The parameter at minimum stop
I've replaced a fuel pressure valve/regulator connected to Delphi pump (brown connector) and then in Bosch service they did another check on the regulator, it is ok. They also checked injectors after 35kkm after repair last year and they are like the ones from a new car. What could be a problem here? EGR? Turbo? any sensors or just HP pump?
Here is a screenshot from Polish diagnostic software MaxiECU which shows fuel rail pressure. https://megane.com.pl/uploads/imgs/hosti ... _blad2.png
Purple one is a fuel rail pressure and blue one is the fuel pressure needed. What I can see is that the fuel pressure is sometimes around 100bar too low.
Fuel filter changed for Kamoka and in next two days I'll change it for original MANN filter. I've opened previous filter and there were no metal particles in it. After injectors has been repaired a year ago, injection fault was still showing up.
Can someone help please?
BTW:Sorry for my English. I'm from Poland.

Darek

PS. Maybe this chart will be more relevant. Chart at the top. Green - fuel rail pressure, Yellow - fuel pressure needed, Blue - throttle pedal position, Purple - engine RPM https://megane.com.pl/uploads/imgs/hosti ... 317__2.png