Losing boost full throttle

[Wull100]

Hi all,

Cant find any answers to this problem I'm having.

Sorry for the long winded post just want to provide as much info to inform anyone who may have ideas. Videos at the bottom hope they work 1st time uploading to YouTube.

In our Vancouver group there are 3 of us having the same problem. I have not tested all combinations in which it will happen at this stage but here are a few conditions I have found it under so far.

• With or without launch control
• in sport or comfort mode
• from a stand still or under 2k rpm
• 1st or 2nd gear tested only at this stage.
• Automatic or using shifters
• 1 guy is completely stock 2018 GT2 and a 2019 GT2 with an AEM intake (this guys issue started before he installed the AEM intake)
• I have Borla and AEM intakes (recirc hose removed and intakes capped) 2019 GT2. We are all AWD as that's all we can get in Canada.
• 2018 has 47,000 km 2nd car 2019 32,000 km and mine is 21,000km.
• No codes are thrown.
• Only happens if tank is under half way.

Once in full acceleration from a stand still or slow crawl like idle speeds, using the conditions above the car will go limp between 4k & 6k rpm. More often it's around 4k rpm but a couple of times it happened at 6k rpm, just can't recall what I did differently for it to be at 6k rpm, possible starting at a slightly higher rpm. It holds that rpm until you let off the gas which it will change gear and resume driving. 2 of the guys have taken it in to 3 different dealerships and the techs don't know what the problem is as no codes are thrown. The 2018 had been in the shop for a week while they did diagnostics and they could not figure it out and called it a day. Closing his ticket with nothing wrong stated.

My wife took my car in and they said they could not replicate my problems. I sent them a spiel of the problem with 2 videos showing the issue. I made them take my wife out so she could show them the problem. They are now aware of the issue. Of course they say, well you have an after market exhaust and air intakes and that requires a tune. Which it doesnt.

Anyway they want to take it for 7 days, run some test to see what's up. I know they are going to come up blank as they did it the guys 2018 after 7 days of testing. There is no such thing as a mechanic in these places. No problem solvers. A bunch of tards that need a code to fix something.

Just weird at over 1/2 a tank no problems. As soon as its 1mm under the 1/2 way mark it starts playing up.

Appreciate your time guys and any ideas I can try.

 

[SoCalSHO]

I cannot add much, but do you have the gauge screen that shows the boost and oil temp? Might be something to look at, but just as a reference.

And I think that our cars actually cut power, to save gas, when the tank is under 1/8th full. If true, might be the fuel level sensor that cuts the power under an eighth, might be bad.

And wasnt there a recall over a burr on a fuel injector or something like that? Just tossing out ideas.

 

[Wull100]

I cannot add much, but do you have the gauge screen that shows the boost and oil temp? Might be something to look at, but just as a reference.

And I think that our cars actually cut power, to save gas, when the tank is under 1/8th full. If true, might be the fuel level sensor that cuts the power under an eighth, might be bad.

And wasnt there a recall over a burr on a fuel injector or something like that? Just tossing out ideas.

Hi SoCalSHO, thanks for the response. I can looking this sensor you speak of. As for the fuel pump issue I believe that is for a select period of manufacturing between 2020/2021 models.

 

[Hacksaw907]

Following this thread - I had this issue, but only when I had my racechip on. Switching to a jb4 fixed it at wot, but I can still trigger limp mode if I gradually go to wot instead of just flooring it. I was thinking it was overboost, but since you know of someone who had it happen right at stock, that might not be the case. Also have aem intakes and a borla exhaust

 

[Stingerr]

I had the same issue for weeks
But finally I fixed
I replaced the spark with the densos ikh27 and regap to .18

Intakes
Full exhaust
Cat delete
vr Tunned box 2

 

[cncBilly]

I had the same issue for weeks
But finally I fixed
I replaced the spark with the densos ikh27 and regap to .18

Intakes
Full exhaust
Cat delete
vr Tunned box 2

.018 is pretty skinny. What did you have in there to start and what gap.

 

[Wull100]

I had the same issue for weeks
But finally I fixed
I replaced the spark with the densos ikh27 and regap to .18

Intakes
Full exhaust
Cat delete
vr Tunned box 2

Same as in nothing wrong if fuel over half a tank? Then once under half a tank the problem starts? Just want to be sure. My car went in yesterday and if yours is identical I want to tell them to try that.

 

[Hacksaw907]

@Wull100 any updates on this issue? Curious to see what the dealer finds

 

[Wull100]

Not yet mate. Car has been at the dealers for over a week. Will get an update tomorrow as I need the car Saturday to put my winter tires on.

 

[Wull100]

@Wull100 any updates on this issue? Curious to see what the dealer finds

Just dropped off my stock exhaust and intakes. They want to reinstall the to eliminate these mods being the issues. Will see what happens. If these are the problem some how, I will get rid of the car if it cant be modded. Dont see how the exhaust and intakes could be the problem. Many people have exhaust and intake mods but not the issue I'm having.

They checked spark plugs on drivers side and said they are good. They didnt check passenger side to my knowledge.

 

[Hacksaw907]

Hmm... If that's actually it, that would be a bummer indeed. I'm perfectly fine flooring it in map 0 (stock) with all the mods I have, so I'd frankly be surprised if that fixes it. I'll see if I can find time to check my plugs this week - it seems most people's issues with limp mode triggering stem from there

 

[SoCalSHO]

Updates Yet?

 

[Wull100]

Updates Yet?

They called me today. They have removed my exhaust and intakes and put it back to stock as per Kia Corporates request. The problem still exist. They have recreated the problem and have the data logged. That has been sent to kia corporate. 24-72hrs to get a response from them to see what's steps they are to take next.

 

[SoCalSHO]

Thanks! Good luck.

 

[Hockster]

Wonder if this is related? Recall by Kia US for fuel issues.

https://www.cars.com/research/kia-stinger-2020/recalls/

 

[Wull100]

Wonder if this is related? Recall by Kia US for fuel issues.

Wonder if this is related? Recall by Kia US for fuel issues.

https://www.cars.com/research/kia-stinger-2020/recalls/

Nope its not

 

[Wull100]

Well 6 weeks later they say it's fixed. Fuel pump like I advised them the day I dropped it off. They installed it today and now the problem is gone. They will reinstall my borla and intakes and I can pick it up tomorrow.

 

[DoctorStiches]

Forgive me i didnt read each post ^_^

Could be as stated above the spark is blown out at a certain point. .028 is how i gap mine.

Fuel cut would act different and i hear your BOV so thats a throttle cut in my mind.....

I actually have no ideas on this one :/ maybe
check with smoke to try and find any leaks in your intercooler piping or around the throttlebody perhaps? Could be a leak to atmosphere making the car way lean and the ecu steps in as seen above..... thats the best ive got.

 

[SRV]

OP, appreciate you following up and telling us the fix.

Were the other 2 in your group able to get their cars fixed too?

 

[Wull100]

Not sure mate. It has now happened to ke twice. They replaced it both times. If it happens again I will be expecting more than just replacing this fuel pump over and over.