Author Topic: Power loss - Source found - It's meant to be like that!  (Read 5729 times)

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  • Posts: 583
  • au Australia
    ACT
Ok, I found a potential issue with the i30 diesel manual which I feel some others are experiencing and misdiagnosing as brake drag.

I had this happen twice on the way home tonight, once while trying to correct a under steering situation (Which turned nasty when the power to the engine was cut mid corner, resulting in liberal amounts of handbrake being used) the other time, when flashing my brake lights after overtaking a car that kept it's high beam on.

Ok, first situation, entered a long sweeping right hand corner that was slightly slick with recent rain. This particular corner changes to positive camber just before the apex, continuing through until it straightens up. As the i30 started to under steer, I did some left foot braking (Trail braking) to pull the front end back into line and try get the back end to follow around to help line up for the apex. After braking for 1.5 seconds, I lost all throttle. Thinking there was an issue with fuel starvation (First thing that entered my head) I lifted off the throttle slightly, then applied it again.

Nothing........

I was now severely under steering towards the armco at a great rate of knots.

Only thing I could do now, was to grab the handbrake just enough to lock the inside wheel, helping turn the rear back around on a controllable arc.

A little puzzled, everything felt fine as I accelerated away down the road.

A little further up the road, overtook a vehicle, it kept it's high beam on, so I flashed the brake lights quickly, twice, they kept their high beam on, so I gently rested my left foot on the brake peddle, just enough to illuminate the brake lights (Which are VERY bright on my vehicle) this I could see as the high level brake light lights up the hatch area.

As I am trying to accelerate away, the engine suddenly lost power, like if I lifted off the throttle.

Flooring the throttle resulted in no response from the engine.

Hmm.....

I took my foot off the brake peddle, immediately the engine came to life and accelerate away.

Ok, what is going on, is it brake drag?

So I did this again, further down the road, watching the Scanguage for Engine load and manifold pressure.

As you would expect with brake drag, the load on the engine would increase, and boost pressure would increase if you floored the throttle and applied a little bit of brake.

This is not the case, boost pressure dropped and engine load dropped, just like when you lift off the throttle.

Now I am only applying the brake enough to illuminate the rear brake lights, not enough to engage the brakes themselves.

I have a full tank of fuel, running the stock exhaust.

I pulled over, turned the engine off (After cooling it down for a minute) unplugged the Scanguage, tested, same thing happened again. Ok, ruled out the Scanguage.

Maybe it's the LED tail lights? I unplugged them, drove down the road again making sure no one was behind me, problem remained.

I'm about to write a very thorough letter Hyundai Australia asking if this is a 'feature' of the i30, and if it can be turned off.

If not, I will be requesting Hyundai Australia to take my vehicle back.

I would like to 'drive' my vehicle, not have some 'nanny' electronics cut power when I need it most, almost causing my vehicle to run off the road! (No, I do not have ESP on this vehicle)

Just thought I'd let you all know about this.



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  • Posts: 41,606
  • england England
    Manchester, UK
    • i30 Owners Club
Re: Unexplaind power loss - Source found
« Reply #1 : October 21, 2008, 07:25:01 »
That's a strange story, but very well told. I tried to picture in my mind the various scenarios as you described them. It spooked me.

Anyway, I was under the impression that braking told the ECU to shut off the fuel supply ("fuel runoff" is it called?). I'm sure I read it on here somewhere that this is what happens. If I can't find it here I'll try and remember where I saw it... it was only in the past couple of days.
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  • Posts: 23
  • au Australia
    Kalgoorlie
Re: Unexplained power loss - Source found
« Reply #2 : October 21, 2008, 07:39:45 »
Very weird.

I know the computers in the VZ Calais i had would shut down the throttle if the car were stationary and you hit the brake & throttle at the same time. (trying to do burnouts)
But if the car were moving it would not shut it down?

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  • Posts: 41,606
  • england England
    Manchester, UK
    • i30 Owners Club
Re: Unexplained power loss - Source found
« Reply #3 : October 21, 2008, 11:19:21 »
I can't find where I read about what I wrote but it'll crop up soon I'm sure.

I tried the theory out on my drive back home and sure enough, as soon as the switch lights the brake lights, the power is cut.
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  • Posts: 23
  • au Australia
    Kalgoorlie
Re: Unexplained power loss - Source found
« Reply #4 : October 21, 2008, 11:44:11 »
A 'fail-safe' maybe?
If the electronic throttle screws up? (stuck in WOT for what ever reason)
Or maybe in an accident situation? (the vast majority of 'normal' or 'safe' drivers on the road really are shocking when confronted with an emergency situation, panicking and mashing any or all pedal's on the floor! )

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  • Posts: 272
  • au Australia
    Sydney, NSW, Australia
  • Hyundai i30 CRDi '07 100,000km
Re: Unexplained power loss - Source found
« Reply #5 : October 21, 2008, 12:01:26 »
i dont know if its any help, but previously when i bought new wider shoes and changed to alloy pedals, which had a toe and heel lip on the brake and throttle [which i later removed]. Unknowingly until it happened, i heel and toed around a corner but i heard the engine reving as well as when i was pushing the brake...

maybe this could have been implemented on early models/later models (not sure when you all bought your cars) for a fail safe for accidental left foot braking e.g. a manual driver when driving someone else's auto will automatically react to hit the left two pedals which will be the brake and accelerator in the auto car (read various articles on this in the nrma mags)...but then again, it could also be that its just my car that didnt have that activated? Maybe it something in the ECU that can be activated/deactivated?

if anything ill give it a try tomorrow when i go to uni and see if the power is cut or it it continues to rev for my car...

you could email hyundai australia thumper? i think that they have a faster reply time in their email customer service rather than postal.

hopefully more people can test this and see if they get the same reaction as you thumper?

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  • Posts: 41,606
  • england England
    Manchester, UK
    • i30 Owners Club
Re: Unexplained power loss - Source found
« Reply #6 : October 21, 2008, 12:10:44 »
FOUND IT.

Not the same article I read previously but has the same words.

Quote
In addition, many modern vehicles use a "Drive By Wire" or Electronic throttle control system instead of the traditional mechanical throttle linkage. These systems have a safety interlock that prevents left foot braking. The car's ECU can detect when both pedals are pressed simultaneously and will immediately cut the engine power for safety reasons.

(from Yahoo! Answers)

I'm going to turn off ESP tomorrow to see if this ETC is linked to ESP.
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Re: Unexplained power loss - Source found
« Reply #7 : October 21, 2008, 18:31:27 »
Thanks for the support all, I thought I was going crazy.

Yes, there are many reasons why you would want to left foot brake in a vehicle, to dry your brakes after going through water, whilst still accelerating, or to help transfer torque from one wheel that is spinning, to another wheel that has grip (Very useful when on ice, like the other week. No wonder I have massive problems trying to drive up the road when it was covered by black ice, I was using the left foot the 'drag' the brakes to help transfer torque from one wheel to the other, the engine kept dieing on me)

Left foot braking can help settle a vehicles path when cornering at higher speeds.

Ok, granted, most drivers have no idea how to perform this, nor would know what left foot braking does, but for those who regularly perform left foot braking, this is the first EFI vehicle that kills the throttle when the brake is applied. (This is my fifth Hyundai, and the first to do this)

In any vehicle that has an open diff, left foot braking whilst applying power is the only way to help transfer torque from the wheel that has no grip, to the other wheel that has grip (Performed all the time when 4WD'ing)

Email to Hyundai Australia is being drafted now.

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  • Posts: 81
  • au Australia
    Melbourne
Re: Unexplained power loss - Source found
« Reply #8 : October 21, 2008, 19:31:05 »
Thumper,
Surely the Traction control and ESP take care of the icy conditions?? (that is assuming that you have them fitted). If not can understand your concern.

Re: Unexplained power loss - Source found
« Reply #9 : October 21, 2008, 19:49:03 »
I do not have traction control or ESP (My i30 is one of the first to arrive in Australia) So no cruise either!

Ok, email was replied to, and like the previous email about the DPF, was useless.

I explained the make, model, year of manufacture, and options fitted.

Was told in email that ESP and traction control take care the vehicles handling under those situations.

Grrrr....

So I rang Hyundai Australia, spoke to technical section, then customer care.

Yes all Hyundai diesel vehicles have this 'feature' *Sighs*

They are NOT racing vehicles, and should not be driven that way! (Excuse me? It's called advanced driving in emergency situations!)

I should not be driving the vehicle that quickly on Australian roads! (Ok so 1st gear going up a hill is too quick? Ok........)

It is software based and can not be turned off. (Uh huh, so how was the code written in the first place?)

ESP and traction control is fitted so you should not need to use the brakes and accelerate at the same time. (Again, I said my vehicle does not have these fitted. Must of spoken to the same drone that answered my email)

All new Hyundai's do not suffer from any water ingress into the brakes, thus no need to 'dry' the brakes after driving through water. (This is utter crap, mine suffers badly from lack of brakes when they are wet.)

If I am driving in those conditions, then I should have purchased a 4WD. (Ok, this is where I started to loose my cool, since I was driving on normal sealed highway road from the COAST of NSW. Since when do you need a 4WD to drive on normal Australian highways and city roads?)

I asked what can be done to rectify this issue, was told bluntly that I own the car now, it's up to me to sort it out! *Blinks, dumbfounded*

Thank you Hyundai Australia. As an owner of five Hyundai's, going on the refusal of providing a second key, now this, you've just lost a long time consumer, and future customer.

I will now be selling my i30 and looking elsewhere for a vehicle that can be driven! (Not one that stops me driving)

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  • Posts: 272
  • au Australia
    Sydney, NSW, Australia
  • Hyundai i30 CRDi '07 100,000km
Re: Power loss - Source found - It's meant to be like that!
« Reply #10 : October 21, 2008, 23:40:23 »
ah crap >< the hyundai customer service lines know nothing at all bout the car...you could try call into your dealer's service department?

noooo...we cant lose thumper  :cry:

and since its software based, it should be POSSIBLE, not easy though to locate etc etc, to bypass this coding! maybe you need to get in touch with a higher level, since hyundai australia only distribute cars? there should be a global HQ or something?

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  • Posts: 41,606
  • england England
    Manchester, UK
    • i30 Owners Club
Re: Unexplained power loss - Source found
« Reply #11 : October 22, 2008, 02:09:35 »
I forgot you didn't have ESP. Either way I'll try turning mine off in an hour or so and see if it disengages this "feature".

Quote from: "Thumper"
...(This is utter crap, mine suffers badly from lack of brakes when they are wet.)...
Gotta agree with that
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Re: Power loss - Source found - It's meant to be like that!
« Reply #12 : October 22, 2008, 06:44:40 »
Well, after some testing today, on the way to work, I've found a fail safe (A way to bypass) the throttle kill while braking.

All you need to do is lift off the throttle completely, then reapply.

Tested several times, it works.

Now I know why I had some much trouble on the black ice!

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  • Posts: 155
  • au Australia
    Victoria
  • i30 CRDi sx Steel Grey 28/11/08
Re: Power loss - Source found - It's meant to be like that!
« Reply #13 : October 23, 2008, 04:13:43 »
off the throttle completely then reapply? are you still left foot braking at that point? or does the engine only come back to life after both feet lifted and tap/reapply the accelerator?

from someone who hasn't got there i30 yet this seems dangerous in a whole heap of circumstances... not that I'm Michael Schumacher with the left foot brake or anything. i'd look at getting this option removed, might be for elderly woman drivers or something lol no one two foots an auto like my grandmother...

is this 'feature' in the automatics aswell?

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  • Posts: 272
  • au Australia
    Sydney, NSW, Australia
  • Hyundai i30 CRDi '07 100,000km
Re: Power loss - Source found - It's meant to be like that!
« Reply #14 : October 23, 2008, 04:37:48 »
hey, i tested it today, and the same problem happens with me. wow..left foot braking takes some getting used to since the left foot is always pushing the clutch >< lol....but when i tap and release the accelerate and repeat, im pretty sure the power comes back in....but i dont think i should try this any more till i do that advanced drivers course later this year...just incase i get myself in a predicament i dont want to be in without esp! lol...but aww...sucks to hear you are selling your i30 thumper... :cry:

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  • Posts: 17
  • au Australia
    Townsville
Re: Power loss - Source found - It's meant to be like that!
« Reply #15 : October 23, 2008, 06:02:17 »
For interest's sake. I can add that the symptoms Thumper described also occur in the Nissan Xtrail (automatic w/ ESP) I drive as a work vehicle. It might be a sign of a 'modern' vehicles to come. Yech!

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  • Posts: 610
  • au Australia
    Bindoon, W.A.
  • Bindoon, Western Australia.
Re: Power loss - Source found - It's meant to be like that!
« Reply #16 : October 23, 2008, 06:11:15 »
Yeah mine loses power too when i tap the brake, but only for about 3/4 of a second, then the power comes back smoothly without releasing the throttle.

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  • Posts: 272
  • au Australia
    Sydney, NSW, Australia
  • Hyundai i30 CRDi '07 100,000km
Re: Power loss - Source found - It's meant to be like that!
« Reply #17 : October 23, 2008, 07:07:08 »
yeah, i heard through a review that the 350z does that as well, but you can bypass it through deactivating the brake light switch or something after the pedal...

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  • Posts: 53
  • pl Poland
    Bytom, Poland
Re: Power loss - Source found - It's meant to be like that!
« Reply #18 : October 23, 2008, 15:10:06 »
i'll test that tomorrow in my i30. looking forward for results. how to test it exactly ? any advices ? i've never braked left footed in i30(maybe once, when i wanted to be like Sebastian Loeb :P but it was in Peugeot 206 SW )

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  • Posts: 25,658
  • england England
    Wirral
  • Wirral, UK. - 1.4 Petrol Active - Aqua Blue
Re: Power loss - Source found - It's meant to be like that!
« Reply #19 : October 23, 2008, 15:41:38 »
Quote from: "sopel"
i'll test that tomorrow in my i30. looking forward for results. how to test it exactly ? any advices ? i've never braked left footed in i30

1. Make sure there is no one behind you.
2. Make sure road ahead is clear.  Do not use main road/dual/motorway.
3. Drive normally to reasonable speed, say 30mph (50 kph), then while keeping right foot on the gas put left foot gently/slowly on brake pedal. You can put more pressure on as you feel comfortable. If to heavy you will brake suddenly and cause car to dip forward and possibly cause crash!
  • 1.4 Petrol Active       I'm no expert, so please correct me if I'm wrong

Re: Power loss - Source found - It's meant to be like that!
« Reply #20 : October 23, 2008, 21:12:04 »
It happens in every gear, so you can test in an empty parking lot in 1st gear, low speed.

Haven't tested it in reverse, yet.

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  • Posts: 53
  • pl Poland
    Bytom, Poland
Re: Power loss - Source found - It's meant to be like that!
« Reply #21 : November 15, 2008, 13:40:09 »
ok i tested this.
and when i have my foot on the brake, slightly pushing it (brake lights on) , i can accelerate, but when i press brakes harder and try to accelerate, i can't do it. maybe brakes are too good :P

Re: Power loss - Source found - It's meant to be like that!
« Reply #22 : November 15, 2008, 20:56:51 »
Quote from: "sopel"
ok i tested this.
and when i have my foot on the brake, slightly pushing it (brake lights on) , i can accelerate, but when i press brakes harder and try to accelerate, i can't do it. maybe brakes are too good :twisted: