Hyundai Forums banner
1 - 18 of 18 Posts

·
Registered
Joined
·
31 Posts
Discussion Starter · #1 · (Edited)
Hello,

I currently drive a 2015 Hyundai Sonata Limited 2.4L.
Does anyone else have an issue with their engine startup?

What I mean specifically is that when I start up the engine, the RPM number the engine starts up to is different almost every time.

I believe when it starts normally, once the engine starts, the RPM should initially be at 1.5 - 2 RPM.. and gradually go down. Sometimes my car starts this way “normally”. Other times it starts when warm at 1 RPM initially.. sometimes starts hitting less than 1 RPM initially.. (at times it feels like the ignition somehow barely started the car)

Those with this car (2015+), could you let me know of the following? :
1) What the initial RPM goes to when you start the car when cold
2) What the initial RPM goes to when you start the car when warm

I feel as though my car starts at abnormally low RPMs but trying to see if this is common amongst other owners as well.

Any thoughts on what the issue might be as well?
Thank you in advance for your input.
 

·
Registered
Joined
·
393 Posts
I experienced all of sudden low rpm, low power , hesitating engine , shaky/ vibration steering and engine light came on with P0304( misfire cylinder 4) and realised I was driving lower than L mark on oil dip stick, erased the error code and started car again after 10
Minutes and it’s good since then also I cleaned up my spark plugs after that, used sea foam fuel additive treatment thinking to use CRC GDI intake valve cleaner.

1. When cold rpm goes around 1.5k and slowly drops

2. When it’s warm it hits around 1100 rpm and go down slowly to 6-7 k rpm.


My car used to have idle rpm around 700-750 rpm Now it dropped at 600-650 rpm when in idle and also steering feels vibrating when in ‘D’ and stopped at signal lights or brakes engaged.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
258 Posts
altitude air temperature, humidity, air quality, engine temperature, air intake are just a few variables that play a part in startup RPM. it's gonna be different pretty much every time. keep in mind your car has parts that expand and contract different amounts every time the car is running and stopped. it may be a difference of 10rpm, may be 100 or 1000th. nothing to lose sleep about at all
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #4 · (Edited)
altitude air temperature, humidity, air quality, engine temperature, air intake are just a few variables that play a part in startup RPM. it's gonna be different pretty much every time. keep in mind your car has parts that expand and contract different amounts every time the car is running and stopped. it may be a difference of 10rpm, may be 100 or 1000th. nothing to lose sleep about at all
Thanks for the reply but the thing is it’s different almost every time at home.
I only feel as if when it starts up at initially hitting 1500 rpm or more, its feels like it starts normally..

Every time it starts at 1000 rpm or less.. it feels like the car somehow barely started.. (like a hesitation start on half crank) it should’ve failed but somehow it actually came alive.
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #5 ·
I experienced all of sudden low rpm, low power , hesitating engine , shaky/ vibration steering and engine light came on with P0304( misfire cylinder 4) and realised I was driving lower than L mark on oil dip stick, erased the error code and started car again after 10
Minutes and it’s good since then also I cleaned up my spark plugs after that, used sea foam fuel additive treatment thinking to use CRC GDI intake valve cleaner.

1. When cold rpm goes around 1.5k and slowly drops

2. When it’s warm it hits around 1100 rpm and go down slowly to 6-7 k rpm.


My car used to have idle rpm around 700-750 rpm Now it dropped at 600-650 rpm when in idle and also steering feels vibrating when in ‘D’ and stopped at signal lights or brakes engaged.


Sent from my iPhone using Tapatalk

Thanks for your response. Checked the oil levels and its fine on my end.
Thanks for letting me know your initial startup RPMs.. seems similar to mine.

When its warm, do you feel that the car has a hard time starting? Or it starts “cleanly” like it did when it was cold?

Thank you!
 

·
Registered
Joined
·
258 Posts
Thanks for the reply but the thing is it’s different almost every time at home.
I only feel as if when it starts up at initially hitting 1500 rpm or more, its feels like it starts normally..

Every time it starts at 1000 rpm or less.. it feels like the car somehow barely started.. (like a hesitation start on half crank) it should’ve failed but somehow it actually came alive.


if it's truly hesitating, check your engine air filter and have the spark plugs and drive belts inspected.
 

·
Registered
Joined
·
393 Posts
Thanks for your response. Checked the oil levels and its fine on my end.

Thanks for letting me know your initial startup RPMs.. seems similar to mine.



When its warm, do you feel that the car has a hard time starting? Or it starts “cleanly” like it did when it was cold?



Thank you!


Yes I have felt few times when engine is warm it does not start in half key turn or one full key turn so I give it a rest of a minute or two and then it start up fine.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
285 Posts
Hello,

I currently drive a 2015 Hyundai Sonata Limited 2.4L.
Does anyone else have an issue with their engine startup?

What I mean specifically is that when I start up the engine, the RPM number the engine starts up to is different almost every time.

I believe when it starts normally, once the engine starts, the RPM should initially be at 1.5 - 2 RPM.. and gradually go down. Sometimes my car starts this way “normally”. Other times it starts when warm at 1 RPM initially.. sometimes starts hitting less than 1 RPM initially.. (at times it feels like the ignition somehow barely started the car)

Those with this car (2015+), could you let me know of the following? :
1) What the initial RPM goes to when you start the car when cold
2) What the initial RPM goes to when you start the car when warm

I feel as though my car starts at abnormally low RPMs but trying to see if this is common amongst other owners as well.

Any thoughts on what the issue might be as well?
Thank you in advance for your input.

Idle speed at normal operating temperature: 625 RPM. Cold starts: 1000 RPM (even in the winter).
 

·
Registered
Joined
·
689 Posts
yes once in a while I also experience a 'weak' ignition. But most of the time it's OK.
I expect my morning ignition to feel strong, like a "boom" . But once in a while starting the car in the morning feels like starting it when it's already warmed up, where there is not "boom" feeling at all. I have a push button start though. So not sure if holding the button down longer will make it choke longer.
 

·
Registered
Joined
·
333 Posts
yes once in a while I also experience a 'weak' ignition. But most of the time it's OK.
I expect my morning ignition to feel strong, like a "boom" . But once in a while starting the car in the morning feels like starting it when it's already warmed up, where there is not "boom" feeling at all. I have a push button start though. So not sure if holding the button down longer will make it choke longer.

It is a fuel injected engine... so no choke...
 

·
Registered
Joined
·
333 Posts
Have you been using Top Tier Fuel, or adding Techron regularly. The GDI engine is notorious for having plugs, injectors etc start to get soot-ed up. Top Tier or Techron is listed in the Owners manual as a requirement. Not sure about the Great White North, but here in the Lower 48, Costco has Top-Tier fuel.

https://www.consumerreports.org/car-maintenance/study-shows-top-tier-gasoline-worth-extra-price/
https://www.toptiergas.com/licensedbrands/

Also you might think about doing a Intake valve cleaning.. as the fuel cleans do not touch the intake valves.

There are a couple of threads here about DYI CRC Intake cleaning.
http://www.hyundai-forums.com/lf-2015-sonata-i45/627026-2015-2-4l-intake-valve-cleaning-how.html
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #14 ·
yes once in a while I also experience a 'weak' ignition. But most of the time it's OK.
I expect my morning ignition to feel strong, like a "boom" . But once in a while starting the car in the morning feels like starting it when it's already warmed up, where there is not "boom" feeling at all. I have a push button start though. So not sure if holding the button down longer will make it choke longer.
Yup.. you described it exactly like my car.. same here.. i have the push button start.. I’m wondering if this is normal now..
 

·
Registered
2017 Sonata Sport 2.0T
Joined
·
2,038 Posts
Changes in startup and idle is supposed to be one of the early signs of intake valve carbon build in the GDI engine.

Ive also experienced old spark plugs to contribute to this, if you have a turbo I believe 45,000 miles is the recommended change and it never hurts to do them a little early.
 

·
Registered
Joined
·
689 Posts
how many miles you go wootang?

i did bring this to the dealer a while ago and since they could not replicate it, then nothing got done.
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #17 ·
how many miles you go wootang?

i did bring this to the dealer a while ago and since they could not replicate it, then nothing got done.
I’m at 42k.. non turbo.. i have been recording my startup and it changes almost every time... perhaps it could be that it needs new plugs..
 

·
Registered
Joined
·
2 Posts
Have you been using Top Tier Fuel, or adding Techron regularly. The GDI engine is notorious for having plugs, injectors etc start to get soot-ed up. Top Tier or Techron is listed in the Owners manual as a requirement. Not sure about the Great White North, but here in the Lower 48, Costco has Top-Tier fuel.

Study Shows Top Tier Gasoline Worth the Extra Price
https://www.toptiergas.com/licensedbrands/

Also you might think about doing a Intake valve cleaning.. as the fuel cleans do not touch the intake valves.

There are a couple of threads here about DYI CRC Intake cleaning.
2015 2.4L Intake Valve Cleaning...How?
I have a 2015 Hyundai Sonata SE. I've had this exact same issue from mileage 50K to 59K until I went to the dealership to get a 60K service. After the fuel induction service it cleared the irratic idling the car had when I started the car up. Believe it is due to the carbon buildup in the intake manifold.
 
1 - 18 of 18 Posts
Top