The Mégane II Owners' Club

I have a 1.9 dci 120 bhp 53 plate.
Turbo has been replaced and all the associated work that comes with it.
The problem now is when a accelarate past 3000 rpm ,when i let my foot off to change gear the engine shuts down for a second and the check injection flashes up,then its ok until i put my foot down past 2500 - 3000 rpm .?
Turn off the car check injection gone and all is fine until 3000 rpm again.
Could this be the wastegate on the turbo?
I know it can be adjusted but dont want to unless its safe to do.
Or could it be the engine breather system?
Any help please as its driving me mad!!!!!!

I'm confused and ill informed about this. I thought that the boost actuator could be moved by hand and the turbo is a variable vane type and therefore has no wastegate.

I await correction. In the mean time have a look here at cleaning the breather system: https://www.meganeownersclub.co.uk/forum ... =2&t=11440 (scroll down a bit).

Im not sure then???
I thought that the valve looking thing in top off the turbo with the vac pipe was the waste gate?
If not what is it and what would adjusting it do?
I am totally confused and ill informed from my technician friend if i am wrong!!!
Any ideas what the problem could be?
Could the breather system cause the engine to shut down momentarily after boost ?

Your boost pressure sensor could be faulty.

is there any way of testing it because its not bringing any codes up?

Have no idea. There should be a fault code stored.

Checking any codes would be a good idea - although I'm not sure that boost pressure is a measured parameter. I don't think you can log it, but you might find some odd codes to point you in the right direction.

You may well have read / contributed to this thread, but have a check just in case: viewtopic.php?f=2&t=13171

any one got some input on this as i am stuck on what to do next.
Could the breather system shut the engine down after boost if it was malfunctioning?

I'm stuck on this one. First off, does the car rev in neutral past 3k without problems? Secondly, when you say the engine 'shuts down', does it stop - or does it refuse to go above 3k? If it is the latter case, for some reason it would appear to be in limp mode. Thirdly, does this happen all the time? Fourth, do you get the STOP light on or is it just 'check injection'? Fifth, is the problem temperature dependant? Sixth, who replaced the turbo and with what did they replace it - is it a direct match - there are many types of F9Q engines. Seventh, does the turbo sound normal? Eighth, can you move the turbo actuator by hand - and does it move when you start the engine?

Without answers to these questions it is difficult to know what to say.

Personally, and this is just guesswork, the boost pressure situation may turn out to be a red herring. Mine comes on boost at around 1500 - 1800rpm and remains so under load.

I suggest you try to log any parameters surrounding the mixture / lambda settings and give some indication as to exhaust smoke. The problem may be down to the wrong turbo being fitted, the breather system being blocked (chucking in extra engine oil at high engine rpms) or some other fault.

See also Alex's thoughts on a similar matter:

viewtopic.php?f=2&t=13200

i have fitted 3 turbos to my megane 1.9 dci and i fitted the second one twice. the first two i bought where knackered but when i was running the oil out of the intercooler and the exhaust my car kept going in to limp mode at 3k but now that all the oil is burnt off it is fine.

also when i connected it up to my mates renault clip he said the check injection fault was one or more glow plugs down so they all got changed. wonder if the oil in the engine may of brought that fault up.

hope this helps

Hi,
here we go then
1st. The car revs in neutral fine past 3000rpm no problems.
2nd. When it happens the engine just stops but then comes back on again.
3rd.The problem happens most off the time upon acceleration ,when the throttle is released.
4th.It always bring up check injection and sometimes the stop light as well.
5th. The temp has nothing to do with it,it happens hot or cold.
6th. I fitted the turbo and its an exact match.
7th. Turbo sounds fine and the actuator move by hand and when the car is started.

I had an idea and replaced the new actuator with the one on the blown turbo because i knew the setting was in the right place.
The fault happens a lot less now but mainly in first gear when i really put my foot down past 2500rpm.
In 2nd,3rd,4th does not really happen at all now.
The fault must have something to do with this.
Would the actuator be set for the turbo or to the car?

Any one???

I would help if I knew the answer. Have you looked at the online manuals?

One thought, try logging the absolute calculated load value with an ELM.

Read the OBD codes and record the real-time diagrams. It looks like the ECU detects a dangerous condition and shuts down the engine for a while. It can be overboost, increase in fuel pressure or just a mismatch in sensor readings (mass air flow does not match temperature-pressure-revs combination). Were the intercooler+ducts cleaned/replaced alongside with the turbo? Is the EGR valve clean?