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MJD :Engine tune and EGR

Discussion in 'Engine Compartment' started by Sat-Chit-ananda, May 14, 2012.

  1. bhai

    bhai Esperto

    Grande Punto 1.3 90 HP
    Yes ! Differance remarks on valve timing of multijet,DDiS & quadrajet is wriiten as per discussion with Drifter.I had discussed about effects of bad fuel. He replied & cleared my doubts about how adulterated fuel affects the performance.I can't write complete discussion here. But in short following is the theory.As per drifter replied following is my conclusion. Inlet charge of fuel should burn out completely before closing of exhaust valve. (Before entering new charge in combustion chamber)Adulterated fuel can't burn fastly. Combustion process becomes so lethargic that there is need more time to complete combustion process.. More time to complete combustion means to close exhaust valve lately. & to open inlet valve lately.If combustion is not completing at the time closing of exhaust valve. Then new induction charge comes in through inlet valve.Then new & old fuel charge are mixed & engine starts to knock. & that time when we rise the throttle, we get feeling of suffocation in combustion chamber & power loss. Abnormal negative pressure is created in crankcase.But in M Swift exhaust valve is closed lately. There is more time to complete combustion before opening inlet valve than Multijet That's why diesel with kerosene added does not affect so much performance in DDiS.P.S. :-As per my info , all parts are not same in DDiS. While manufacturing DDiD engine,MSIL has deleted 2 parts from original multijet engine.1. Oil cooler & 2. Knocking sensorAbout oil cooler I am sure coz this info I had got from FIAT officials.But I am not sure about deletion of knocking sensor. Is there anyone who can confirm this ?
  2. sungoa2010


    Are you sure that oil cooler is not there in DDIS. To avoid confusion can you first mention what is meant by oil cooler and it's function.
    From the below link I could understand that oil cooler exist in DDIS. DM's Maruti Suzuki Swift Vdi: Problem with the EGR valve
  3. bhai

    bhai Esperto

    Grande Punto 1.3 90 HP
    I have read this blog earlier. The blog contains discussion about EGR cooler not oil cooler.

    When DDiS engine was introduced first 1-2 years msil was using oil cooler.
    But after 2 years, DDiS engine encountered problem of mixing of oil & coolent.
    MSIL engineers could not find the solution on it. So they gave up & eleminated oil cooler. New batch of DDiS engine doesn't have oil cooler.
    in DDiS engine. This info got from Mr. Mangesh.

    Oil cooler keeps oil cool & maintains viscocity of oil. EGR cooler keeps EGR gas cool before entering in inlet manifold. Multijet has oil cooler & egr cooler while ddis has only egr cooler.
    Last edited: May 23, 2012
  4. vIjAy_kHaSa

    vIjAy_kHaSa Esperto


    Maybe MJD have Speed Limiter and not RPM Limiter. In our cars the ECU doesn't know in which gear car is running so maybe the Top Speed is limited to prevent users having too much fun.
    Don't remember fully but I think the Linea crosses 3500rpm in 5th gear so should be same in Punto.
    Last edited: May 23, 2012
  5. It is called rev limiter , whether it is looking at gear+speed and the RPM I don't know,not sure how a Linea or 90HP engine revs beyond 3500 RPM.
    in 76 BHP Punto it can not go beyond 3500 RPM in 5th gear, i guess it sets the fueling to a constant value ignoring the throttle position.

    ---------- Post added at 08:50 AM ---------- Previous post was at 08:39 AM ----------


    I have driven both non-drive tech and drivetech models, still car can go beyond 170 kmph,whether you call it speed limit or rev limit on 5th gear,it is built in the ECU.that is the difference.
    if you see the video i posted ear liar, you can see the ODO and RPM of Vista.

    My self and thebalck have test driven our cars extensively,there is some thing that limits the speed of 76BHP max 160 and 3500 RPM,Siddarth tells me it is rev limiter that only kicks in 5th gear found in high end cars only !!
    Out punto's can find out a blown number plate or brake light, I tend to believe it can find out the speed,current gear and RPM and use all of them or some of them to limit the fueling to a constant value ignoring the TPS out put,no matter how hard we are on the throttle.
    I read some where changes to map was done after Sep 2010 models,so no surprise you donot see the a tad sluggishness in your car.
    Mine is Mar 2010 and it is BS4,actually older the emission standards car tend be peppier as exhaust tend to have more liberty!!


    ---------- Post added at 09:02 AM ---------- Previous post was at 08:50 AM ----------

    SX4's handling is not as good as Vento and don't even compere both them to Linea, Linea is miles ahead of both.
    Problem is soft sprung suspensions and EPS,once beyond 120 steering feels like joy stick.it is heavy car it gives a feeling it's planted but not beyond 120.
    If a person is driving SX4 for long time he can take the car to it's limits on straight lines and slight curves but it does not induce confidence for person test driving it unlike our Punto and Linea.
    Last edited: May 23, 2012
  6. theblack

    theblack Esperto

    To add to Sat-chit-anand's answers about rev limiters @ 3500..
    We(me and him) have taken the car to 4500 in 4th and no matter how swiftly we change to fifth the RPM drops between 2800-3200 and never picks up beyond 3500 after that.
    When he TD my car he hit 140kmph in 4th at 4300RPM(with AC) itself with nearly 500mts to spare but chucking it into 5th was just not working at all..
    The overall length of road was about 1km and we easily hit 4300 but never managed to get beyond 3500 in 5th
  7. puntosat

    puntosat Superiore

    Are you sure ??

    I am almost sure I hit 4000 rpm at 5th gear and at 150kmph....mine is 2012 Punto..

    In fact I was constantly at 160 kmph for about 2 kms..near Kunigal on NH48...and rpm was 4000...

    I will re-check this weekend..
  8. jayadev

    jayadev Esperto

    Kannur, India
    Grande Punto 1.3 90 HP
    Possibly true.

    Try revving in fifth gear with clutch pedal fully pressed.
    1 person likes this.
  9. Italia-Linea

    Italia-Linea Staff Member Janitor

    Perfectly said Jayadev. If there is such limiter then you can press the clutch and revv in 5th gear. check at what rpm you face jerks i.e fuel cut off.

    Regarding number plate bulb fused etc, lets keep that part out of discussion.

    Its not controlled by the Engine ECU.

    Officially MAP was changed only when the specs were changed to 93ps. Later on all cars have same specs. This was done when i was there with FIAT.

    On the engine test rig we have seen MJD ranging from 88 to 110 bhp in stock form. Every engine behaves differently with all identical parts and maps. so 2 lineas made on same day can drive differently.
  10. theblack

    theblack Esperto

    200% sure. our puntos are 09 models (75HP) .
    which variant do you have.
    I've done 160 as well but not at 4000


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