Independent Renault Forums banner
1 - 20 of 30 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter · #1 ·
Hello !
I am the proud owner of a Laguna 3 made in March of 2010.
The BIG problem with it is that it hits heavy on the smoke when I hit heavy on the throttle.
I went to a official Renault service, they did not know what's wrong with it. Went to several different mechanics, no answer. Nobody knows why my car does this.
The symptoms are:
-under heavy load, the car smokes a lot (black smoke, no other colors)
-idles poorly when hot (not stopping but runs rough), when cold no problem
-no hissing sound when revving (like it should be something wrong with the turbo/inter-cooler hoses
-no visible damage to the turbo/inter-cooler hoses
-good air quantity on intake values
-turbo gives a lot of pressure (up to 3 bar easily)
-fuel economy is good (50 MPG in the summer with climate control on, 60 MPG the rest of the time)
-no visible damage from any hose that can be seen from the front
-ABSOLUTELY NO DTC PRESENT WHATSOEVER
-battery is a little low but it starts just fine, should replace soon though
-if I unplug the MAF sensor and start the car, it idles perfectly and little to no visible black smoke is emitted, only when really really hard on the throttle but it is expected as it runs from the lookup table and not real life data
-car did not come with diesel particulate filter, it is Euro 4

I replaced the original MAF sensor with a new one from PIERBURG- same problem.
Cleaned the EGR (it was a little bit black but very light coat but nothing serious) -same problem.
Air filter is new. (I replace it every 5500 miles, when I also change the oil).
Injector correction values are as bellow:
Rectangle Grey Font Parallel Pattern



I have no clue what to do with it. Please help !
 

·
Super fantastic Mod Technical Supremo Nice Guy
Joined
·
39,465 Posts
Take cover off your engine and post a picture of your engine
 

·
Registered
Joined
·
320 Posts
Hello I have a very similar problem with my 2004 Kangoo 1.5 dci K9K 704 with the exception of mine idles perfectly at all temperature's but mine did start to hesitate as it warmed up when under load but this was a recent development. Unfortunately I have not got to the cause of the problem so far. The only thing I can suggest which made no difference to mine but is worth checking is the PCV easy to get too on yours. Now I have made progress I believe as I pulled the Intake temperature sensor and gave it a good clean and the hesitation stopped and the smoke did not look as bad so I have got a new one but cannot fit it yet as I am in the UK for a couple of weeks. If you have not solved your problem by the time I get back to Bulgaria and fit it I will post the results, to be honest I am not that hopeful Just a thought but the van had an emission test a short while ago and passed with flying colours so its fine at idle and at about 2500 rpm.
Best of luck
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #5 ·
Hello skippy glen
Mine did not have the problem with the idle until recently. It developed over time, like in your case. On those engines the intake temperature and the MAF sensor are in the same module. Unfortunately I replaced the module on my car but it did not solve anything (Pierburg module, it is one of the best replacements on the market).
If I unplug the whole thing from the system, I get an error (but it's normal as it does not detect the two sensors) and the idle problem disappears entirely. The smoke gets gentler (at low loads, no smoke, only when under-revved its smoking) . If I floor it, the smoke is there again even after unplugging. I suppose this is because the car enters a "limp mode" and is injecting far less diesel than it's supposed to.
 

·
Super fantastic Mod Technical Supremo Nice Guy
Joined
·
39,465 Posts
You have given it a really good run
Try this first before you clean the pipework from EGR to the inlet manifold
Get the engine up to temp
Now find a quite country road

Get the car around 2, 000 rpm
Now dip the clutch, and hit the accelerator until it nearly red lines.
Allow the engine to slowly decelerate, ( RPMS dropping down to normal ) and slowly lift off the clutch to regain control,
Do this 6 or 7 times ( Should do this before you take the car for its MOT )
This will clean all the excess black smoke from the piston crowns, and also loosen the soot built up in the inlet manifold..
See if that cures it first, if not, then its clean the Inlet manifold pipework, at the back of the engine
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #7 ·
Update: changed the diesel fuel supplier. Put a supposedly better diesel with more additives. Now it barely smokes with the MAF sensor unplugged but if I plug it and floor it gray smoke is coming, but a bit less.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #8 ·
Update 2: plugging in the MAF and it smokes like hell again.

Which sensor information is being ignored when you unplug the MAF?

It could be that sensor alone which is making this **** happen. Unplugging the MAF solved the problem again but it is not advised to run with it unplugged for extended periods of time...
 

·
Technical Supremo.
Scenic II, 2004, K4MW761, DPO
Joined
·
7,432 Posts
You need a Renault speaking scanner to tackle this methodically:

IMO - when you unplug the AFM, the ECU runs on default "safe" tables for timing and fuel quantity based on MAP alone if there is no separate IAT sensor on this model ............... and if the MAP is funky for whatever reason, things go titsup.

So - scanner - what is MAP and boost pressure readings with the ignition on and the engine not running? - if IAT (or any intake air temperature-related values) is reported what is that?

-turbo gives a lot of pressure (up to 3 bar easily)
For some reason this sounds iffy ............... scanner will define "3 Bar easy" but I doubt that - if that sensor is an absolute pressure sensor and the ECU allows around 1.6Bar boost relative to ambient, then at most you should see 2.6Bar

Question - do you have injectors that needs coding or is you ECU oblivious to that?

If they need coding (scanner) are the injectors properly coded per cylinder? .............. those correction values looks funky to me
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #10 ·
So - scanner - what is MAP and boost pressure readings with the ignition on and the engine not running? - if IAT (or any intake air temperature-related values) is reported what is that?
Pressure with engine off is ~1 bar. So 3 bars means +2 bars boost in best case scenario.

Question - do you have injectors that needs coding or is you ECU oblivious to that?
If they need coding (scanner) are the injectors properly coded per cylinder? .............. those correction values looks funky to me
Yes I have injectors that have to be coded but I also have a CAN Clip Renault tester, and they are properly coded. No problems with the injectors. Funky values indeed, Renault seems to do this reading in a very peculiar way, as I have read on other forums/topics, values should be as close to 1 as possible for the injector to be in best shape.

Another problem which I see is the rough idling. And it's getting rougher sometimes, sometimes it stops being rough. It does it only when the engine is slightly warm, I can't understand why. Yesterday I hit it a little (sudden acceleration from 0 rpm to 4500+ and letting the accelerator pedal loose afterwards, 4-5 times) and it magically stopped smoking like crazy, I cannot understand why. Today, in the morning, same issue, black smoke. At idle it does not smoke, but if I rev it, even when not under load, just sitting and revving, it gives some little cloud.
If I unplug MAF sensor, the symptoms are gone, again. As I said, MAF is new, Pierburg one.
I suspect the MAP sensor because of the symptoms (rough idling, black smoke when hitting a little gas, hesitation while sudden acceleration).

Yesterday I also put the tester on it, and it gave me funky fluctuating values on the parameter "Air flow loop difference". I don't know what this means, but it was giving me very funky values when rough idling and then magically stabilize.
 

·
Technical Supremo.
Scenic II, 2004, K4MW761, DPO
Joined
·
7,432 Posts
Yes I have injectors that have to be coded but I also have a CAN Clip Renault tester, and they are properly coded. No problems with the injectors. Funky values indeed, Renault seems to do this reading in a very peculiar way, as I have read on other forums/topics, values should be as close to 1 as possible for the injector to be in best shape.
Correct - each individual value should be 1 when all is well for THAT cylinder. A value of 1 means the calibrated flow curves contained in the specific injector code and entered into the injection computer, are adhered to by the mechanical characteristics of the engine ................. you will find the sum total of the 4 individual differences from 1 of the compensation values to be always equal to 0 .............. in your case : (-0.003 )+ (-0.039) + (0.077) +(-0.036)

This characteristic is because the injection computer normalizes the compensation values to achieve a smooth running engine - you can view individual cylinder compensation values as an attempt by the computer to either add or subtract an amount of fuel so that the engine's cylinders all contribute the same power per stroke.

Any way out large compensation difference from calibration means you have a funky cylinder or funky injector (in your case cylinder 2 may be suspect)

"Air flow loop difference". I don't know what this means, but it was giving me very funky values when rough idling and then magically stabilize.
I am going to guess this is the difference between measured MAF flow and calculated flow using the MAP/IAT/etc ........... and certainly could be the cause of fueling issues
 

·
Super fantastic Mod Technical Supremo Nice Guy
Joined
·
39,465 Posts
Injectors are reading good nothing to worry about on them on a renault diesel,
Back of your engine you need to clean the crud out of this pipe

Gun accessory Machine Metal Auto part Fashion accessory

The one above the manifold
 
  • Like
Reactions: LvR

·
Technical Supremo.
Scenic II, 2004, K4MW761, DPO
Joined
·
7,432 Posts
Injectors are reading good nothing to worry about on them on a renault diesel,
Back of your engine you need to clean the crud out of this pipe

View attachment 197712
The one above the manifold
This is rather important and cannot be stressed enough ............... fix ALL the mechanical stuff first (including blocked/gunked-up pipes etc) BEFORE you start chasing things electronic.

There are no parameters found on any scanner anywhere that can/will tell you to fix anything mechanical................ and then, once you reach the point where a scanner is the last resort you need to be extremely methodical about it
 

·
Registered
Joined
·
320 Posts
I have been following this with some interest as I have been chasing a similar problem for months now and I believe ours is correct in his diagnosis. But but bear with and shall give what I believe is an explanation to the funky results which are not stable and can send you in the wrong direction. I believe what is happening is the inlet tract is becoming so blocked that it is restricting the airflow and when the EGR valve opens it is cutting the oxygen levels to a critical point that there is not enough oxygen levels to burn the fuel correctly hence the black smoke. To prove a point I have disabled the EGR and the smoke almost completely stopped. Unfortunately to clean the inlet anywhere near completely on the van is just about impossible without pulling the head. Another sign is the smoke is worse when the ambient temperature is high as warm air contains less oxygen. Again this would not have been an issue if Renault had designed the engine with a removable inlet but alas no but there it is. To be honest I think this may effect cars that have had Turbo issues or problems with excessive oil entering the inlet as the heat and soot from the exhaust would tend to congeal the oil. That is about my best take on what the problem could be. Before anybody throws a fit about disabling the EGR I am not suggesting you all do it. As I say I tried it to prove a point as I new the EGR on the van was working well its not hard to tell if it is opening.
 

·
Super fantastic Mod Technical Supremo Nice Guy
Joined
·
39,465 Posts
No easy fix as such, its stripping and cleaning
Can be sorted in a day

Parts on a car are expensive, when its your own, labour is free
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #16 ·
Hello,
Do you know how the intake manifold and egr pipes can be dissasembled on the 1.5 dci 110hp ? Is the manifold and all other pipes available to be removed without removing the entire engine or engine head ? Because I want to go to the mechanic for that and I don't know if I need a new headgasket or not(in case the head is removed I would not like to put the old gasket back).
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #17 ·
Turns out no, after some research on engine pictures, the answer is that you have to take out the entire head to clean the intake properly. Very poor design for the k9k engine... What do you need when taking out the head ? New bolts and new gasket, anything else ? Mine has the k9k 780.
 

·
Registered
Joined
·
320 Posts
Before going down that road either try what ours2012 says if possible. Also you could try what I have done disable the EGR valve so that the exhaust gasses are not getting into the engine it is not a fix but it worked on mine. If you read my thread on "inlet manifold issues" it explains why this can help, as I say it is not a fix but can alleviate the problem. And to answer your question I would get a timing belt, tensioner and valve cover gasket.
 

·
Super fantastic Mod Technical Supremo Nice Guy
Joined
·
39,465 Posts
Maybe not then
Look at these pictures
Product Rectangle Font Technology Metal


Take scuttle panel off, ( Where wiper arms are )
Now take the panel off below this

Not come across a Renault where you have to take the head off to remove an inlet manifold
 

·
Registered
Joined
·
320 Posts
Maybe not then
Look at these pictures
View attachment 197879

Take scuttle panel off, ( Where wiper arms are )
Now take the panel off below this

Not come across a Renault where you have to take the head off to remove an inlet manifold
Maybe not then
Look at these pictures
View attachment 197879

Take scuttle panel off, ( Where wiper arms are )
Now take the panel off below this

Not come across a Renault where you have to take the head off to remove an inlet manifold
I do believe you may have typed remove where you intended to type clean.
 
1 - 20 of 30 Posts
Top