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Why does the engine smoke and make noises if you directly downshift to first.

Discussion in 'Off Topic' started by Mohameddo-san, Nov 28, 2012.

  1. Mohameddo-san

    Mohameddo-san
    F1 Sim Racer & #1 St. Bernard Lover on RD Premium Member

    When I am up a hill, I wait a moment until the car is in neutral, then, I downshift to first gear because twice I have downshifted to first gear and what I described happened.

    I hardly ever shift to first when I reach a red light about to turn green even though I am not getting enough acceleration.
     
  2. Hiroshi Awazu

    Hiroshi Awazu
    Off Topic Moderator

    How fast are you going when you're doing this? I hope this isn't in your new car.

    And if so:
    Just remember one thing repairs due to "Negligence" is not covered under your warranty, regardless of whether you have the lifetime warranty. Nowadays mechanics can easily tell when owners have been mistreating their vehicles. So be aware of that.
     
  3. Carlos Diaz

    Carlos Diaz
    Happily driving a "girly" car

    It sounds like you might be over-reving the motor. Do you have a tach? Are you going from 3rd or 4th to 1st? Most of the time 1st gear is USUALLY used when taking off from a stand still. Anything over 5 or 10 kph and 2nd is fine.
     
    • Like Like x 1
  4. 4 8 15 16 23 42 108

    4 8 15 16 23 42 108
    Only the 5th-most famous race driver from Kerpen Premium Member

    Can you be a little more specific? You bought a six-speed manual shifter in the Mazda like you planned with the Subaru?
    Here in Germany cars prevent you to put in 1st when moving above a certain speed (maybe 20-30 kph). It is something constructed to make you not go to 1st. Maybe you could hammer it in with raw brutality, never tried). My first can reach 80 kph, so you won't damage it or the engine when driving the car within a town in 1st only [I neglect cold oil and water]. Obviously, 50 kph in 1st is not helping to make your engine last for decades, but I believe your just downshifting after braking/decelerating a lot.
    Like Carlos I need to know which speed and gears you are referring to.

    Smoke coming from your exhaust? Or bonnet? Black or white or bluish grey? What does it sound like?

    To say it short: I cannot put in 1st this way and if I could, nothing would smoke or make noises. Engine would roar^^
    In Germany, we usually lift off the throttle when we see red lights, let the car roll with (in my case) 4th gear still in (no more fuel injected at that point) and use the clutch only when revs drop to neutral rev value. 1st will be in only before accelerating again.

    Just in case: After buying the car, have you checked all liquids, tire pressure and stuff? Only to prevent things like low oil and such.
     
  5. Mohameddo-san

    Mohameddo-san
    F1 Sim Racer & #1 St. Bernard Lover on RD Premium Member

    No, when I owned a '95 BMW 530i, twice, I directly downshifted to first and the engine started to smoke.

    Now, with any manual car, I am reluctant to downshift to first gear unless I fully stop.
     
  6. Marian Zelenka

    Marian Zelenka
    The downforce is strong with this one.

    But that's the way you ought to do it.
     
    • Like Like x 1
  7. At what speed do you put 1st ?
     
  8. Mohameddo-san

    Mohameddo-san
    F1 Sim Racer & #1 St. Bernard Lover on RD Premium Member

    Well, I directly downshifted to first on a stop light.

    William, I would say about 10 km/h
     
  9. Tom

    Tom
    Staff Emeritus Staff

    Could be that you've been slamming the gear in. In this case you should always try to slowly shift into first gear - it'll slide in on it's own, with no force, once it's ok. Push it into the right direction but don't force it into first gear, simply wait until it slides in.

    Hard to explain, I think. :)
     
  10. Bram

    Bram
    Roaring Pipes Maniacs | #27 Staff Premium Member

    What is the reason you do that? You can also brake manually and let the engine do the rest in second gear. Press the clutch before you come to a halt and then engage first gear when you accelerate again.

    Also don't keep your foot on the clutch with first gear engaged while waiting for a stop light for a lot of time. Neutral saves you some clutch repairs :D
     
  11. if its smelly too it could be because your burning up the clutch trying to engage it into 1st
    If the engine makes noises its because your clutching into 1st too early and your speed and revs are too high...in which case the engine will retard heavily to allow 1st gear speeds,and in doing so u may experience a forward motion ,like a forward hop as the car deccelerates,but it'll feel like acceleration and a very loud engine rev...which may explain the engine sound ur hearing.

    improper cluthcing into 1st(without having to stop or overuse ur clutch) is not a pleasant feeling ,just takes time to get used to doing it
    1st gear is ideal when in traffic jams(u can make ur brakes last awhole lot longer if u get stuck in them daily),going down parking garage ramps ,just make sure u bring the car to very low speeds before u engage..and as Tom suggested dont force it in,..it slides in nicely when its all matched correctly
     
  12. More detail needed I think....
    Is it a new car or an old banger?
    WHERE does the smoke come from?
    Under the bonnet, from under the floor or from the rear?
    What colour is it?
    Does it have a particular odour?
    IS it smoke or is it oil mist?
    Does it only happen on a trailing throttle/decelerating or when accelerating?
    It could be many things including oil residue on the exaust that doesn't seem to appear until air-speed drops....
    Possibly the clutch isn't engaging or disengaging properly....

    There's dozens of things that it could be that appear to be smoke whether it's smoke of not.
    Possibly get someone else to drive the car & see if it happens then too, if it does then it may not be your driving style & something actually wrong with the car.
    If it doesn't then swap seats & when it happens ask if they've noticed it & then what your doing wrong when it does happen....
     
    • Like Like x 1
  13. There is no reason at all to go down to 1st on a street car while the car is rolling. Just don't.
     
  14. You should never be downshifting into first while rolling....ever. Talk about stressing a gearbox and clutch. I use first only to get moving. Second is the absolute lowest gear anybody needs to downshift to.
     
    • Like Like x 1
  15. Marian Zelenka

    Marian Zelenka
    The downforce is strong with this one.

    Yeah, but off course it could be different for cars that can make >100kph on 1st gear. :D
     
    • Like Like x 1
  16. Mohameddo-san

    Mohameddo-san
    F1 Sim Racer & #1 St. Bernard Lover on RD Premium Member

    Exactly what I do.

    Though, you definitely need to downshift to first if you are on a VERY STEEP hill.
     
  17. Im sorry Terry,but i have to disagree with you here all the way.
    Not only can u shift into 1st gear while moving,but ive been doing it for years and years!,..and trust me,when done correctly no damage is done to either the gearbox or clutch.
    To put it in perspective , my last clutch survived 7yrs before i got rid of the car and 1st gear was as powerfull as its always been.
    To bring even more perspective into it,i shift into first while moving ..umm about 20times a day,(give or take) ,so yeah ,im not sure where u got this preconception about it,but i can assure you its not it

    i guess the secret of it Terry is alot of foot work:)..which i dont mind..hehe

    edit: and before i get any rebutals as to why its neccesery to shift into 1st gear at all:
    well,instant short burst of power at your finger tips!..of course if i was driving a Ferrari or a Viper i wouldnt really need it!...so i guess it all comes down to what u drive and how aggressive u are as a driver
     
    • Like Like x 1
  18. Thanks Mohammed, in my response I figured the OP was talking about straight line, level driving and yes...you do need it for very steep downhill to allow engine braking. At the time of selection most people are going very slow anyway.
    Ivan.. Unless you are driving an econobox with no torque, I find it hard to see why you'd need to downshift all the way to first. As to clutch life, my original Saab Turbo was sold after 19 years of use and zero clutches (I did install a new one when I first purchased the car)..
     
  19. Seven years is not long at all. Unless you are a taxi driver.

    As for the bursts of power in 1st... I have not a clue of what you are doing with your car!
     
    • Like Like x 2
  20. What´s smoking is your clutch probably. Funny smell afterwards?

    If you want to downshift to first gear while in motion you have to rev-match to not put strain on the engine, gearbox, clutch.
    And you need to be quick to get on the gas otherwise the car will most likely slow down quite abruptly due to the aggressive gearing on the first.