KIA Sportage auto fuel vaporization

WPete on 15/10/2020 - 14:47

Gday All,

We have a 2018 Kia Sportage auto 2.4 litre petrol vehicle. On a recent trip, we noticed that, in cruise control at 110km, the vehicle would change down when reaching an uphill incline. There was a momentary loss of power as the vehicle shifted from 6th gear to 5th, etc. Not every time, but enough to be annoying.

I consulted a friend who's a former car mechanic, and he said he'd seen this problem before in another Sportage. He said it was due to the fuel line being routed too near the engine, so that fuel was partially vaporizing on its way to the injectors. When more fuel was required on a down-change, this caused a momentary shortage of fuel resulting in the loss of power.

I'm wondering if

  1. Anyone else has experienced this problem; and
  2. What you think of my friend's diagnosis?

Looking forward to your insights!

Pete

Automotive Car Kia SUV

Comments

  • Simoneee on 15/10/2020 - 15:15
    +2

    Clutch Slip?

  • Game R on 15/10/2020 - 15:16
    +5

    Sorry, but your friends theory just doesn't add up.. If your fuel lines are getting hot enough to vaporize the fuel in them, it would be much worse when you're driving through city traffic with less airflow to keep the engine bay temps in check and the engine would be using a lot more fuel accelerating from standstill and higher revs than just a drop in gear from 6th to 5th. I'd probably focus on the gearbox as a likely suspect.

  • bobbified on 15/10/2020 - 15:20
    +1

    Let me start by saying that I'm no expert. So what I'm saying next is just a guess based on my own logic. The theory sounds plausible at first, but then thoughts are that if the fuel line is close enough to the engine to heat up enough to vaporise the fuel inside the line, then the rubber fuel line may be a risk of rupturing.

    I would think that it's just the gearbox switching to a lower gear. Every automatic I've driven seems to take longer to shift down a gear while going uphill than it does to shift up.

  • MS Paint on 15/10/2020 - 15:47
    +2

    Sounds like a confused transmission algorithm

  • RED27APPLE on 15/10/2020 - 15:49

    What have Kia said??

    • pegaxs on 15/10/2020 - 16:37
      +6

      “What did OzBargain say when you asked them?”

    • WPete on 15/10/2020 - 16:57
      +3

      Kia (a receptionist) said, "You can't speak to the service manager/mechanic/etc. but you will have to book the vehicle in so we can run some tests to diagnose the problem. We may yet do that. Thanks to those who have commented thus far. My mate actually made some kind of barrier between the fuel line and the head, which, he said, was effective. Sorry, I'm still vague on the details.
      Pete

  • Xistn on 15/10/2020 - 15:51
    +11

    Can now see why your friend was a "former" Mechanic.

    • picklewizard on 15/10/2020 - 18:30
      +1

      LOL I said the same below What a complete load of rubbish! Vapour lock = downshift… ok bro

      • Xistn on 19/10/2020 - 15:11

        I am starting to see a direct link between Karens and "Pete's"

  • netjock on 15/10/2020 - 15:51

    On a recent trip, we noticed that, in cruise control at 110km, the vehicle would change down when reaching an uphill incline.

    Maybe it needs to in order to maintain momentum.

    There was a momentary loss of power as the vehicle shifted from 6th gear to 5th, etc.

    Normal. Like driving manual, if you engage the clutch to change gears you lose power due to being in neutral before engaging in the the other gear.

    Put it down to the quirk of the car that you have bought. Probably not a major problem in the first world.

  • Willco88 on 15/10/2020 - 15:55
    +5

    Isn't that normal?

    Your car will automatically adjust the transmission because you are going up hill, so to take stress off the transmission it will go to a lower gear?

    Nothing new mate

  • Drakesy on 15/10/2020 - 15:57
    +1

    the vehicle would change down when reaching an uphill incline. There was a momentary loss of power as the vehicle shifted from 6th gear to 5th, etc. Not every time, but enough to be annoying.

    This is normal for automatic cars in order to keep the car in the optimal torque band. Given that Sportages aren't powerhouses it's expected. The momentary loss of power as previously indicated is due to the gear change which wouldn't be instantaneous. Just like when you change down in a manual to maintain the revs you'll get a loss of power as you take off the clutch.

    If the OP is coming from a higher torque 4wd or more powerful car i'd imagine this wouldn't have happened previously.

    Oh and if the fuel was vaporizing in the fuel lines then you would have fuel line pressure issues let alone your fuel line's integrity.

  • plmko on 15/10/2020 - 16:10
    -5

    What kind of car shifts from 6th to 5th for an uphill climb? Those are overdrive gears.

    Try 3rd or 4th if cruising.

    • Switchblade88 on 15/10/2020 - 16:39
      +6

      You change into 3rd gear at 110 km/h and let me know how you go.

      • jackinyourbox on 15/10/2020 - 17:51
        +3

        VTEC kicked in - YOOOOOOOOOO

    • knasty on 15/10/2020 - 17:36
      +7

      "What kind of car shifts from 6th to 5th for an uphill climb?" A 6 speed auto which was cruising in 6th but hits an incline.

  • EightImmortals on 15/10/2020 - 18:08

    Does the Kia have a real gearbox or a CVT? If it's a CVT some of them are programmed to make them 'feel' like they are changing gears when they aren't. If it's a proper gearbox then ignore that line of thought. :)

    • knasty on 15/10/2020 - 18:12
      +1

      Sportage is a 6 speed auto.

      • Peter Enis on 15/10/2020 - 18:59
        +1

        Depends, if it's a MY19 2018 model it would be 8-speed.

        EDIT: My bad, only 8-speed in the diesel MY19 onwards

  • Zippy7 on 15/10/2020 - 18:27
    +1

    I have a 2018 Sportage with the 2.4L petrol engine.
    Spent a few days down the coast (~250km trip each way).
    Used cruise control for part of it (bloody roadworks meant I wasnt able to do so for large parts).
    I experienced a flaring (unusual high revving a few times) - gentle throttle on/off then revs flared when reapplying the throttle. Like the gearbox was disengaged (if it was manual, it was clutch disengaged), and had no forward drive.
    I also had the auto emergency braking warning light randomly appear for a minute at a time, 3 or 4 times on each drive. No particular trigger (not like a car was there).

    My previous car was Australian assembled and never had anywhere near as many issues as this car. Thank God I have 7 years warranty - I hope I can count on it to get things fixed, because the customer service experience has been very ordinary (much worse than I had with the Aussie brand).

    • This Guy on 15/10/2020 - 18:47

      Cruise control will usually use a higher gear as the car carn't care less about responsiveness.

      When the driver takes back over, most auto's will drop back down to make the car responsive again. That sounds like what you experienced.

      Most AEB units will pick up false positives. It is a limitation of the technology.

    • deepblonde on 16/10/2020 - 09:14

      The transmission flare sounds , probably transmission clutches are burned, or if you’re lucky the valve body - under warranty get them to replace everything before your warranty runs out - or you could be up for many, many thousands

  • picklewizard on 15/10/2020 - 18:29

    Cars gear down when going up hills. Load on the engine is increased, 6th is an overdrive gear (as likely is 5th, but may deliver sufficient torque at 110 to climb.)

    He said it was due to the fuel line being routed too near the engine, so that fuel was partially vaporizing on its way to the injectors.

    former car mechanic

    I can see why he's not anymore… he's describing vapour lock, which is absolutely a condition but it results in a car stalling, not changing gears.

  • This Guy on 15/10/2020 - 18:38
    +3

    WTF?

    A mechanic said that a momentary loss of power, when a car is out of gear, is due to vapour lock?

    No.

    The gear box is between gears. You loose power because the engine is disengaged from the wheels. It's not a CVT with fake gears. It is a real auto with a torque converter.

    Those gearboxes suck and are slow to change. A KIA tech once told me they have memory and will adjust their change timing based on ~6 months of driver input. A flash would reset it's behavour. It sounded like the crap customer service tells to clients when they can't fix a problem and want the client to leave them alone.

    KIA don't clamp fuel hoses properly after model upgrades. That's about all they screw up.

    Edit: and electronics. They screw up those from time to time

  • ShannonN on 15/10/2020 - 19:58
    +2

    ask on the aussie kia forum if its a common prob they'll id it and offer the solution this is a bargain forum not a solve your every problem site LOL

  • Snake 4 on 15/10/2020 - 20:33
    +1

    It's under warranty for gods sake. Book it int a Kia service dept.

    Oh. Thamk your friend for being an ex mechanic.

  • WPete on 15/10/2020 - 21:00
    -1

    Thanks everyone for your comments: whether helpful, informative, smart-ass, or whatever. Very entertaining to see the quality of the interactions, or lack thereof. I apologise if this was the wrong forum in which to ask my question, and I'm happy to take the advice of ShannonN and raise it with the kia forum.

    (As for the snide comments about my mate's being an "ex-mechanic," I have a lot more respect for his opinions that I do for the opinions of those who dissed him but know nothing of his knowledge and experience. As mentioned in my response to Red85apple, "My mate actually made some kind of barrier between the fuel line and the head, which, he said, was effective. Sorry, I'm still vague on the details." That doesn't prove his diagnosis to be correct, but it's certainly interesting.)

    So, thanks, and farewell.

    Pete

    • picklewizard on 16/10/2020 - 09:20
      +1

      I have a lot more respect for his opinions

      You really shouldn't, he's absolutely talking out of his arse.

      know nothing of his knowledge and experience

      You told us everything we need to know.

      • Xistn on 19/10/2020 - 15:09
        +1

        Remember to get the blinker fluid serviced!!!!! XD

  • Snake 4 on 15/10/2020 - 22:00
    +3

    Don't forget to turn the light out.

  • gbarlett on 16/10/2020 - 07:59
    +1

    "He said it was due to the fuel line being routed too near the engine, so that fuel was partially vaporizing on its way to the injectors"
    not possible when the fuel pressure in the fuel lines is 300 to 400kpa, it would have to be glowing.
    its just a characteristic of the transmission.

  • OzHunterNSW on 16/10/2020 - 10:08
    +1

    I find your friends's explanation utterly implausible. The delay is resultant with your particular gearbox, coupled with your selection of cruise control.

    It is a fine line between maintaining constant speed and governing of motor. The loss of power is completely normal.
    You will also notice this temporarily loss when driving without cruise control.

  • Darron65 on 16/10/2020 - 13:48

    Why don't you experiment a little? Next time try manually selecting 1 gear lower just before the hill. See what happens. Leave the cruise control engaged.

  • smhto on 16/10/2020 - 16:44

    I would've thought this is a question for the fuel pump

  • Bignudge on 16/10/2020 - 19:57

    Honestly, if I really wanted to know if it was a fuel problem….. I'd try and floor it at the lights from a standstill until changes from first to second gear. If it was to stutter, it would do it then when under wide open throttle.

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