The Mégane II Owners' Club

Hi folks, I covered this subject in an earlier thread ( viewtopic.php?f=2&t=22448#p124855) which I started over 2 months ago. I have solved the problem and here I summarise what happened and what action I took. Hope this helps somebody, somewhere. 1.5DCI 03, 100k miles
THE PROBLEM
The dreaded "check injection" appeared plus the SERVICE light.
The next morning the car would not start. After about a dozen pushes of the button, it was possible to "catch" it on the throttle and get it running. This was accompanied by clouds of white/blue smoke and I mean CLOUDS which filled the road! After just a few seconds the clouds cleared and the car ran as normal. Hot starts during the day were no problem. The poor cold starting however, continued.
ACTION TAKEN
Applying logic, I checked the glowplugs - all dud. Replaced them and checked operating voltages and timings which were spot on. Made no difference. Found the CTS was under-reading. Replaced. No difference. Fuel filter had done 74k miles so changed this too. Lovely job! Made no difference.
EOBD SCANNER
Bought a little hand held job from ebay. Useless. Could only read the engine ECU, not the fuel or any of the other ECUs. Could not see or delete fault codes. The instrument stated that the MIL was not on! Rubbish. Perhaps this was because the car was pre-2004 when EOBD standard was launched?
Subsequently I tried two more EOBD scanners, both expensive (one attached to laptop). Neither could access the fuel ECU.
Luckily I had access to very sophisticated instruments costing upwards of £4000.
Several fault codes appeared, some of them caused by me (ie when I removed CTS lead). The main code was "injector number 2 control at minimum". The fault codes were deleted. The car started perfectly the next morning. Problem solved? Not so likely! Five days later, the problem returned complete with smoke and error messages.
INJECTOR TESTING
I deleted the codes again, removed injector no 2 (counting from flywheel end!) and took for test at my local fuel injection specialist. For a tenner I was told the injector was in gwo. This threw me off the scent completely! The darned thing WAS faulty!
Once again starting was OK until a few days later.....you guessed it!
A leak-off test revealed that leakage was not a problem with any of the injectors.
I deleted the codes yet again but this lasted only a few days.
Sorry, this is beginning to sound like Fred Karno's circus (whoever he was!)
Courtesy of my brother, lecturer in motor engineering at a college, I was able to hook up to a really good machine but this revealed nothing during the realtime display.
INJECTOR REPLACEMENT
With hindsight I realise that I was obsessed with the clouds of smoke, not realising this was a symptom not a cause. The smoke appeared to be unburnt fuel and I had theories about injector leakage etc. No air leaks could be seen not even at the venturi return.
Having got nowhere I did what I should have done in the first place - purchased two used injectors from ebay - risky, I know. I tried them both and they appeared to work. £38 for the two.
YOU HAVE TO DELETE THE FAULT CODES FIRST!!!
I learned the hard way that if the car won't start because of an injector fault, replacing that injector will not help the starting. Only deleting the fault codes will do that! It may seem obvious to some and it does to me now. It seems to me that once the fault codes have been logged, the injection system is put into some kind of "fault mode" but not LOS (limp home) or it would not run normally when hot. I do not know what a 1.5dci runs like in limp home but a Ford Focus TDCI, for example, makes it obvious as it will not rev over 3,000 RPM if even that high.
For about the fifth time I deleted the DTCs - and waited and waited. I played the waiting game and thankfully the car has remained fault free since and runs well. Phew! Fingers uncrossed, big sigh of relief!
SMOKE ON COLD STARTING IS A COMMON PROBLEM
I have spoken to several other owners who have had this exact problem so it must be fairly common. At the outset I wandered into the workshop of the local Renault dealer and asked the mechanics if they had any idea about the smoke. They were helpful but could offer no suggestion other than "bring it in for computer diagnosis - the days of logical diagnosis are long gone!" They must themselves have experienced this problem but if so, did not say.
So where did the smoke come from? I never did find out but what I did notice that whilst trying to start the car, smoke was belching out of the exhaust with every turn of the engine before it would run. It was quite incredible and I gained the impression that this was unburnt fuel evaporating in the exhaust system

I have rambled on a bit here as usual. I was fortunate having access to diagnostic equipment at no charge but this will end soon when brother retires....Time, perhaps, to get rid of the old fat bum. We have had some battles since my daughter bought her 6 years ago and I'm still victorious....so far. Next jobs, rear discs and pads, annoying suspension rattle and pretty soon, clutch replacement (luckily no DMF on this early model). The list is never ending and every time she speaks to me it is to report a problem (or is it my imagination?). Luckily, being long retired, my time costs nowt!
Will be pleased to receive any comments.
Regards to all, Mike

hopefully your sorted , i have a little black smoke on some cold morning start ups and have but it down to 1 or maybe more heater plugs been u/s

Great insight there Mike, I'm sure it'll prove useful to others. Thanks for that. Hope to goodness that this issue is sorted.

Regarding changing however, is it better the devil that you know (probably too well) or do you chance another model / make ....... I know I've changed a few times and lived to regret it.

Thanks for the update Mike hope it's sorted. Did you have to recode the ecu for the different injectors?

Well postieboy, it is strange that you mentioned that. I was going to make this the subject of another posting.
Everybody in the car trade will tell you "new or replacement injectors must be coded to the ECU". The manuals will also say this.
One mechanic friend said "car will not start without coding".
All my life (three score years and ten) I have done things with cars that were deemed not possible or not advisable. The proof of the pudding is in the eating! The fact is I did not code either of the replacment injectors to the ECU although to have done so would have been easy with the correct equipment. However the injector I finally selected as being the best, did not have the label with the sixteen digit code. A number had been engraved on the metal but was impossible to read. Thus it was not possible to amend the ECU settings. Yes, we all know the theory, that the injector flow patterns are obtained by the maker Delphi (or Bosch) on machinery which costs the earth and the ECU amends the amount of fuel injected accordingly. This might well be so but I am sure that this is minor tweeking and makes littel difference in practice. With an uncoded injector our Megane runs as well as it ever has, performance and economy-wise. Purists will no doubt wince but, as I said before, the proof of the pudding is in the eating.
Oh, and for good measure, the part number of the replacments is not the same as the ones that were in the car - so that answers another question I posed recently!
Cheers, Mike

I'm glad it is fixed, and I would love to know if this has also fixed the problem we were having here with the engine momentarily holding back ?

That's a good question and one I have not forgotten about. Probably too early to say as the car is still on short trips only but a long un is imminent. I will keep that other listing updated. (I just asked daughter no 1 and she has not noticed the problem. She did a 50 mile fast run last week so it is looking good.)

Off topic here, and to answer a question you asked recently. 2.5PI mark 2 1970, Tahiti blue, manual with OD. owned by me since 1975. The passage of time is not doing either of us any good so our "marriage" is likely to end this summer. All good things come to an end but I am going rusty and the car has backache! In unrestored condition (which must be unusual) I no longer have the enthusiam I once did.
Cheers, Mike

Good to see you have sorted it Mike!

Im still on the same trail as you at the moment.

I deleted the fault codes and all was well and good for a few days, perfect first attempt starting in the morning etc... then BEEP "injection fault" and SERVICE light appeared again. As you say, back to the big clouds of white smoke.

I too believe that the starting sequence is put into limp mode, as soon as the faults are deleted it works perfectly again. Annoying as the cheaper OBD readers cant access the fuelling computer to delete these codes.

Im going to give it a go this weekend and see if it can be sorted, going to cut off the quick release connectors replace them with jubilee clips and replace the fuel lines (lines have drained themselves when I look at mine on a morning)

Does anyone know where the NRV is that stops the fuel going back to the tank?

Cheers, Liam.

I know it's going to be answering a 3 year old question in this thread but hey someone else might benefit.

The main NRV in Renault Kangoo is almost 50 or 70 cms after the main fuel supply line from the tank outlet in front of the right rear wheel well under the car. It looks like a regular plastic hose splice connector but actually it's a one way passage check valve. Also the hand bulb pump serves as a second NRV although not as non permeable as the first one.

It sounds like you might be dealing with a common issue in diesel engines, especially during cold weather. Poor cold starting and clouds of smoke can often be linked to fuel delivery problems or glow plug issues. It's essential to get your vehicle checked by a qualified mechanic to diagnose the dissertation writing services cheap exact problem and address any error messages. Timely maintenance and proper care can help ensure smoother cold starts and reduced emissions.