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Change in performance as per fuel qty. or quality & at diff. temperature

Discussion in 'Engine Compartment' started by bhai, Mar 26, 2013.

  1. bhai

    bhai Esperto

    Messages:
    1,183
    Ahmednagar
    Grande Punto 1.3 90 HP
    I observed following weired fact.

    Suppose I have 5 ltr. bad fuel with kerosene mixed.
    I put good fuel approx. half tank.
    Fuel gauge is showing absolutly half tank.
    Then due to good fuel I start to get better performance.
    But as the fuel gauge comes near reserve mark performance start to decrease.

    Is it due to less fuel in tank OR
    Density of kerosene is lighter than genuine diesel. So as the kerosene enters which is bottam of tank enters in engine & drop in fuel gauge drop in performance?
    Do I always keep fuel level more than half tank?

    OR

    Is it programming in ecu?
    I mean engine runs on lean mixture as per signal to ecu from fuel gauge?

    One more thing. I get differant performance at hot noon & differant performance in cool evening & night.

    Please explain.
    Last edited: Mar 26, 2013
  2. ansal11

    ansal11 Esperto

    Messages:
    1,373
    Noida
    I have no answers to your imaginaton !!!!!



    This one can be answered by every Man who doesnt even own a car !!!!!

    May be in Hot Noon, one gets too much miffed with too much sweat.

    Different and better performance in cool evening and night is expected due to the romantic ambience. :evilsmile
    3 people like this.
  3. amar_gahir

    amar_gahir Amatore

    Messages:
    76
    Delhi
    Bhai, i agree with you, certainly its not imagination. I have been observing it for last 3 yrs and 55K of driving.

    Ansal11: sorry but you are not making any sense to me. Its technical forum and keep your "imagination" for FB.
    Last edited: Mar 27, 2013
  4. vIjAy_kHaSa

    vIjAy_kHaSa Esperto

    Messages:
    1,352
    Panchkula
    My car performs same at half tank and when in reserve. Get the fuel tank cleaned and why not fill with good fuel only. I have been seeing your kerosene theory from so many years and still you fill with kerosene. In this much time you could have tested each and every fuel pump in your city and decide which have pure diesel.
    Difference in peppyness at diff times of day is due difference in temp and humidity levels etc etc. Also in noon AC usage is more and compressor runs at full capacity while in cold temp fiat's AC run at low capacity, like invertor technology spilt AC's we have in homes. Even models without ACC have same compressor.
    Last edited: Mar 27, 2013
    1 person likes this.
  5. PatchyBoy

    PatchyBoy Esperto

    Messages:
    2,438
    Bangalore
    The density theory makes sense. Kerosene being less dense that Diesel, will float on Diesel and the Kerosene content entering the engine would be more as the fuel level reduces. Kerosene has poor lubricating qualities as compared with Diesel, hence the performance drop.

    The same would also apply for hot noon Vs. Cool evening and night. I know of cases where people intentionally mix kerosene and diesel for use in very cold climates. It is actually called Winter Diesel. Not so sure, if the climates where you live has such temperature drop in the night to be able to see a noticeable performance drop.

    Why don't you just flush your tank and start using good fuel only?

    Rajan
  6. SHASHANKREDDY

    SHASHANKREDDY Superiore

    Messages:
    631
    HYDERABAD
    Hyderabad
    Grande Punto 1.3
    One straight Observation on my Punto.
    Top up in Highway petrol Bunks( Mix of Kerosene might be more ) - Performance Drops - Feels more sluggish
    Top up in Renowned Petrol Bunk - Ease of drive. Eager to work more.

    My Mechanic says Maintaining Half tank + Fuel level is good to Fuel pump & Diesel filter.
    1 person likes this.
  7. Performance difference between noon and evening might be due to difference in air density. During evening time, air is relatively cooler and relatively high in density; result in better performance than noon time. By the way: it is may be correct theory and may not be true in real world.
    1 person likes this.
  8. bhai

    bhai Esperto

    Messages:
    1,183
    Ahmednagar
    Grande Punto 1.3 90 HP
    @ Amar, Vijay,Patchyboy, Shashank & Sounder
    Thanks friends. At least there are few TFI friends who can understand my observations & feelings.
    While some oversmart guys don't miss chance to make fun of other people.

    I tried all reputed pumps in my city. All are cheaters.
    Sales officers oil companies are also cunning.
    As per retired officer of HPCL, adulteration raquete is upto high level officers.
    High ranking officers get bribe. Most creme postings in oil companies are at refinery.
    Simple clerk working at refinery get Rs. 500 per lorry to give clearance to each lorry.
    Sales officers never give reply of complaint in written format. Only gives oral reply.
    Extreme bad fuel I got from COMCO pumps on pune-mumbai express-way.
    Last edited: Mar 27, 2013
  9. SHASHANKREDDY

    SHASHANKREDDY Superiore

    Messages:
    631
    HYDERABAD
    Hyderabad
    Grande Punto 1.3
    Definitely Diesel Quality in Highway bunks is Worst in Quality.
    On Recent visit to my village i filled up diesel at highway petrol bunk.
    I Started from my village to hyderabad. Normally my punto returns me mileage of 20-22 if i maintain speeds below 100.
    As it was monday as i have to reach office i wanted to rush.. so i was on the pedal....first time i felt that Punto engine is literally not pulling i have to
    push full throttle. And the FE Figure it gave was 16 Kmpl which i normally get in City.
    Next time i visited my regular Fuel Station in Hyderabad and went to my village (i have touched 140kmph also) ... the FE figure was 19.6 .
    P.S - Find out good fuel station inthe city and Tankfull everytime. This would be good approach.
  10. imranshks

    imranshks Superiore

    Messages:
    510
    Bangalore
    @bhai My bit on this is, try sticking to Indian Oil bunks only. I don't know how far its true, one of my friends owns a swift and he said Multijets perform best on Indian Oil diesel.

    I had filled Bharat Petroleum diesel once and achieved good FE but the performance was quite poor. I felt as if the vehicle is trying hard to pull itself. Since then I get tank filled on St. Marks Road or BTM Layout Indian Oil bunk.

    Find out which Indian oil bunks are COCO (Company Owned Company Operated), since you can rely on these rather than relying on adulterated diesel at greedy owner's bunk :)

    Hope your issue gets resolved.

    Cheers :)

    Sent from my HTC Incredible S using Tapatalk 2
    1 person likes this.

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