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Tunning of Multijet diesel engine

Discussion in 'Engine Compartment' started by bhai, Apr 1, 2014.

  1. bhai

    bhai Esperto

    Messages:
    1,185
    Ahmednagar
    Grande Punto 1.3 90 HP
    Hi,


    Many of TFI members are facing problem of 'poor performance but no ECU error'.

    After doing lot of observation & homework I have zeroed that FIAT has kept too much margin in parameters of sensors to match with bad fuel quality of India:evilsmile.

    Some may argue that, then why other diesel engines are running without any problem of low/adulterated Indian fuel quality.
    The performance of other diesel engines in India is at par because other diesel engine can't give huge power & torque like MJD. .

    I mean 1.3 MJD is the India's most powerful & most torquy engine in 1000-1400 c.c.engine.

    Engines with more output I mean more powerful & with more torque need genuine fuel quality. Engines with less output doesn't bother about fuel quality.

    FIAT has mentioned somewhere that they have tuned MJD to match Indian fuel quality.This type of R & D & so called matching is become headache for hardcore fans of FIAT Cars.

    Please don't misunderstand. This is discussion not bashing on FIAT India & famous award winning MJD.
    Last edited by a moderator: Apr 1, 2014
    1 person likes this.
  2. GP_Freak

    GP_Freak Amatore

    Messages:
    240
    Chennai/Madurai
    Chennai
    Linea 1.3
    The 1.3 MJD in other countries are also in same power figures. Not just in India. So this is not about detuning for India and Indian fuel Quality. Maybe in General, the engine is detuned every where for poor fuel quality :-D
    1 person likes this.
  3. asimpleson

    asimpleson Esperto

    Messages:
    3,000
    Heptanesia
    Linea 1.3
    Bhai, couple of other points come to mind in this regard. Let me attempt to treat this topic of discussion purely from analytical view with no undue bias towards Fiat. :geek:



    1. [*=1]By and large DDiS and Quadrajet drivers have had better pickups and lesser performance issues. A popular belief with compelling reasons and evidence subjective to more investigation.

      One prime thing contributing to this is the weight of the cars like Swift as against the might of MJD that tips in favour (power to weight ratio). Same can't be said for the Linea, and somewhat relevant to the Punto as well.

      Second and most important, Tata had got their own ECU/Map software developed via specialist help or inhouse, needs to be confirmed what exactly. Even Maruti has done similar modifications to injection system, maybe including injector manfuacturer, maps and fuel pumps, also including modifying core voltages and subsequent bar pressure across the rail and injectors. Hats off to Maruti engineers to get the math about MJD correctly the first time. Maybe due to some ruboff and contribution from their Japanese partners evolutions of SIX SIGMA philosophy and work culture (dont know if that's an apt term to describe it, but hope you got the drift.)

      [*=1]Fiat I believe has used some very good components (mostly world class), yet where they must have failed is better amalgamation to make things peppier and stable from long term aspects. MJD being a Fiat baby conceived and delivered within Turin, Fiat engineers here in India may have dared not and bother not testing it further for reasons obvious. Fiat subsidiary can only be as strong willed as their management here and at Turin want them to be specifically for improvising an already purebred engine. The common perception maybe like challenging the inventors/developers of this engine. Now both Maruti and Tata too to some extent have bought their way out because their engineers have first row view to this MJD marvel and it's functioning. Further there must be good amount of pressure from their managements to make sure this engine is made to their taste, which Fiat rather wanted more than them in first place, being a manufacturer and supplier of cars themselves to maintain clear distinction between their own version vs iterations sold to others. And that has worked very well to benefits of Maruti and Tata etc. since there are always way better third-party things, technologies and tools out there that can further make an engine standout despite inherent design cons, should a company determine to overcome those. They might have figured the MJD's achilles heels and found an effective workaround :smile:.

    Now back to your original argument/hypothesis, there is I suppose more chance that Fiat provided common rail bar pressure regulator might be acting up. Or maybe a sensor in this closed loop is malfunctioning intermittently enough to cause performance issues. There are tools available for these, except one of these days if we can have a pool of data of cars from Fiat that can been checked regularly for these and also access and knowhow to such test mules or testbeds and testing tools. The big question is how. :confused1

    Long shot, unless we are highly motivated to move hills and mountains here. :razz: Again there is always a possibility multiple issues crawling up simultaneously which need to be ruled out case per case.

    Until then we can only propose hypothesis and possible solutions that would not translate to real world sureshot diagnosis and problem solving. Hope you concur.
    Last edited: Apr 1, 2014
    2 people like this.
  4. GP_Freak

    GP_Freak Amatore

    Messages:
    240
    Chennai/Madurai
    Chennai
    Linea 1.3

    Sorry, I was very brief in my previous post since I was just concentrating on the fact that the MJD is not de-tuned for India. It would be really helpful if you can clarify what you exactly meant by 'poor performance but no ECU error' . Is it the performance of FIAT cars or FIAT engine.If you can be very specific, then I can try to get a grasp of the actual problem and contribute better because a decade back when I was in college, I did a study on effects of poor fuel quality on performance of SI engine and retro fitting a CARB SI engine with DI. Of course, it was very crude and the engine never came out to be a true multi speed engine.

    Btw, Its really good that you have touched related to bad fuel quality in India because that is one of biggest reason for Diesel Engine failure other than poor maintenance and manufacturing defects.

    You are comparing the performance of different cars with the same engine or the performance of the same engine in different cars ? Power to weight ratio comes in to play when you are comparing different cars or same cars with different engines and not when comparing one engine to another. Hope you understand they are both are really different. If you wanna compare engines, you load them in a dyno and get the charts to start with.

    About TATAs and Maruti, they are investing time on the engine not because they are really enthusiastic, but because they don’t have the capacity to develop an engine as good as the MJD, they had stripped down the engine to understand the technology and this made changes which has contributed to some refinement. It’s like after the cook has done with all the hard work, the steward serves with nice plates and good arrangement.
    1 person likes this.
  5. asimpleson

    asimpleson Esperto

    Messages:
    3,000
    Heptanesia
    Linea 1.3
    Swift with 1.3 DDiS and Vista with 1.3 Quadrajet or 1.3 DDiS in Swift and 1.3 Quadrajet in Vista, comparing performance..??..what exactly are you saying..? :confused1

    You got me confused again, kindly rephrase again. I am totally missing your point inspite of reading it 10 times, no offense. :???:

    All I implied is the power of cars vs kerb weight is a factor amongst other dynamics and metrics that matter to a car performance, what's the confusion here? Please try to understand the larger context of entire post in which I have mentioned about power to weight ratio.

    Vista Quadrajet is 1140 kgs kerb, Swift DDiS is 1060 Kgs kerb with same engine 1248cc, similar power-torque of 75PS-190Nm.

    Power to weight ratio is "a measurement of performance of a vehicel as a whole, with the engine's power output being divided by the weight (or mass) of the vehicle, to give a metric that is independent of the vehicle's size."

    Whether they are 'really enthusiastic' or not they would know better than you and me, wouldn't they.

    Again they didn't have the capacity in what sense? Lack of engineers for development or lack of funds/other resources or lack of will of management? Yes, you maybe right, so what about it exactly? It's a known fact they didn't develop the engine; they improvised it (as I suggested in my earlier post), the main design is the same here and I am not arguing that.

    Allow me again to disagree about your cook analogy, it is not just about garnishing and presentation and arrangement, it is about altering the recipe for a dish.

    The actual dish here is MJD except they like to call it Fiat's original Multijet or Maruti's DDiS or Tata's Quadrajet or Chevrolet Smartech. :grin:

    More like Domino's Pizza or Smokin' Joe's Pizza. The Mozarella cheese pizza is same, except Domino's Mozarella tastes different since it is believed they use a mix of cheese, made up of mozzarella, Pecarino, Parmesan, and asiago cheeses. It's not about who invented the cheese pizza or how others were incapable of inventing it.. :smile:

    [HR][/HR]GP_Freak, I think you have pretty much misread/misinterpreted/misanalysed my post. :sad: Please read it again. From my viewpoint your post looks like a question come statement come confusion for myself.:confused

    No offense please, but the last thing I want is another unsettling argument on this forum that does no good to the thread or forum :roll:

    Besides my main point, not simply a contention, is also about Bhai's earlier hypothesis on another thread about CRi pump etc. I found his post interesting there too, before he opened this thread about issue of performance loss of MJDs. You can try to understand from there what he means by 'Poor performance but no ecu error'.
    Read Link here — http://www.teamfiat.co.in/engine-co...-power-while-overtaking-11.html#post841899167
    Last edited: Apr 2, 2014
  6. bhai

    bhai Esperto

    Messages:
    1,185
    Ahmednagar
    Grande Punto 1.3 90 HP
    @GP Freak
    I agree with effects of heavy weight & low power to weight Ratio.

    But to override this excess weight & low power to weight Ratio, FIAT has kept
    short gear ratio of Grande Punto & Linea.

    If FIAT has done good homework on gear ratio as compared to Maruti & TATA then
    what's wrong with MJD?

    Why some members including me are facing such type of repeated problem & No ECM Error?:confused:
    Last edited: Apr 2, 2014
  7. gurjinder

    gurjinder Staff Member Janitor

    Messages:
    3,989
    Punjab
    It has SOMETHING to do with the EGR. What exactly it is - I am not sure. But I have a calculated guess that when the EGR solenoid actuator gets stuck, it causes the engine to act weird. Dirty EGR is not really an issue but if the solenoid gets stuck that's when the issue arises.

    Just my hypothesis at the moment.

    Cheers.
    2 people like this.
  8. asimpleson

    asimpleson Esperto

    Messages:
    3,000
    Heptanesia
    Linea 1.3
    And also one that can be a more of a culprit given the no. of people complaining about EGR issues.
  9. GP_Freak

    GP_Freak Amatore

    Messages:
    240
    Chennai/Madurai
    Chennai
    Linea 1.3
    This is what I was pointing out. See, let me try to explain differently. The engine in Swift and the Engine in Punto are same to me. They are the same engines with minute differences in terms of tuning.

    But what is majorly different is the car in which they are present. Some of the basic parameters are no of cylinders, Bore, stroke, swept volume clearance volume, firing Order. These are the very basic parameters to start with for any Engine. Be it CI or SI.

    The moment you introduce the term (power to weight ratio), it becomes a comparison between cars and not engines. If you want to do a generic comparison between engine, then the basics would be to see the power and torque figures.

    Let me explain better, sorry, these lines were not to confuse you. No offence meant and none taken.

    Power to weight ratio comes in to play when
    1. You are comparing different cars Ex : Swift and Punto ( because, unladed weight is different for both cars even if they have the same engine. )
    2. When comparing same cars with different engines. Ex. Linea with 1.3 MJD and Linea with 1.6 MJD ( Power differs here major time)

    So Power weight ratio is not be used for comparison when comparing one engine to another. Hope the difference is clearly understood now. If you want to compare engines, you load them in a dyno and get the charts(POWER VS RPM and Torque VS RPM) to start with. This is a strict comparison of engine.. ( then again, the engine may perform differently in a car if there is RAM effect coming in to play )

    Even with the same engines, with the Fiats Gear raito, it will feel DUD because the just see how the gears are in 1[SUP]st[/SUP] and 2[SUP]nd[/SUP].

    @asimpleson: Thanks for the links. Now I get the drift of what the thread opener had in his mind. The Header says “Tunning of Multijet diesel engine” and thought loud about Fiat detuning the MJD for Indian fuel quality. This has caused the confusion because the 1.3 MJD is with the same power figures outside India too

    @bhai – You should consider changing the thread name ;-) It is just my suggestion. Only after the link provided by asimpleson, I understood the actual problem. It has nothing to do with the gear ratios. Infact, 3 and 4[SUP]th[/SUP] in gear accelerations figures are the best in MJD when compared to other diesels or even petrol. Even when compared to larger displacement engines.

    In my opinion, the 1[SUP]st[/SUP] Gear though very short, it plays a HUGE role when taking off from standstill in steep Ghats.

    Hope the Ratios are correct.


    GearSwiftLinea
    13.5454.273
    21.904
    2.238
    31.2331.444
    40.9111.029
    50.725
    0.767
    reverse3.2503.909

    PS:Typos and Grammar to be overlooked ;-)
  10. bhai

    bhai Esperto

    Messages:
    1,185
    Ahmednagar
    Grande Punto 1.3 90 HP
    Some friends think that I am comparing MJD with DDiS or quadrajet.

    But Iam talking and comparing only MJD V/s MJD.
    When I try other GP & Linea with MJD I always find that my MJD 90 HP is lazy.
    My MJD do not act like new generation superiour CRDi engine.
    It acts like old generation low-powered non-turbo engines. But no ECU error.:evilsmile

    IMO while tunning MJD,FIAT has not considered most important factor affecting engine performance after using engine for some thousands of KM.

    Yes talking about fuel adulteration . Adulteration affects spray format of injectors,pressure of CRi pump,automization of fuel,clogging of EGR after using car on high-class adulterated
    Indian fuel quality.
    Last edited: Apr 10, 2014

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