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Loss of power during hard acceleration

41K views 37 replies 18 participants last post by  bocuevas36  
#1 ·
I purchased a 2016 Sonata Plug-In Hybrid Limited new in May 2016. Whenever I accelerate full-throttle or near full throttle, (like when pulling out in fast moving traffic or on a freeway entrance ramp), the car begins to accelerate well but, quickly reaches 100% power when all of a sudden, it feels like the power is shut off. After a second, full-power comes back until it reaches 100% and is cut again. This cycle will continue until I back off the throttle and keep the power under 80%. I believe what is happening is the engine is reaching the point where the rev-limiter is kicking in to protect the engine, (which is a good thing). I think the problem is with the transmission not shifting to 2nd gear before the rev limit is reached. As you can imagine, this is quite dangerous to me, and to others having to slow down or stop for me. This problem occurs in all power modes, at any temperature, and has been occurring since after the break-in period. (I didn't try full-throttle for the first 1500 miles.) So tell me, is anyone else experiencing this and if so, did you get it fixed?

The sad part of this is: I took the car to my Hyundai dealer who test drove and verified the symptoms. However, when they contacted Tech Support at Hyundai, they were told: "This is normal behavior. The driver should not accelerate at 100%." (Although, Hyundai does advertise a zero to sixty time of 7.6 seconds.) Oh, BTW, this did NOT occur with the Sonata they gave me as a loaner while mine was in for repair.

I am planning to try a different dealer but, am not confident it will do any good if this kind of response is coming from Hyundai. Anyone have any ideas?
 
#2 ·
I just bought a 2013 limited 2 weeks ago and noticed the same problem (that im no where used to or comfortable with).

On the hwy, doing around 60, went to merge into the left lane (very quickly), there was a car approaching fast to close the gap.... i dipped over and stabbed the gas pedal (as i would do with my reg cars) and got NOTHING!...

Out loud i was like WTF!! And obviously the car pulling in fast behind me jammed on his horn and brakes since i created a wall for him to almost run into... (i felt like an ass, and this was not my intention).

Needless to say i will not do this again in this car because i am now afraid to jump into traffic in this car and create a liability (smdh)...

So yeah... ditto on the dead pedal!!

Sent from my SAMSUNG-SM-N910A using Tapatalk
 
#8 ·
The sad part of this is: I took the car to my Hyundai dealer who test drove and verified the symptoms. However, when they contacted Tech Support at Hyundai, they were told: "This is normal behavior. The driver should not accelerate at 100%." (Although, Hyundai does advertise a zero to sixty time of 7.6 seconds.) Oh, BTW, this did NOT occur with the Sonata they gave me as a loaner while mine was in for repair.
I assume the loaner they gave you was not a HEV or PHEV?
 
#10 · (Edited)
My experience is definitely due to the Rev Limiter killing the engine for a second. You are correct "Frank Xu", I am not hitting 40mph. After 2 or 3 cycles of the Rev-Limiter killing the engine, the transmission finally shifts to the next gear.
Yes, "introspection", this happens from a dead stop or on an entrance ramp with the pedal pushed past the "click". I have found that backing off to just before the click, the rev-limit is not reached. However, the car doesn't accelerate very quickly either.

As I said in my original post, this happens in Normal or ECO driving modes, (no Performance mode on Sonata plug-in), and when using the EV, HEV, and CHG power modes.

I called Hyundai Corporate and logged a case for this so, I will see what they say. "Frank Xu" may be on to something with the transmission re-programming idea. I really feels like it hangs in each gear way too long and also seems to spend an unusually amount of time between gears when driving "normally".
 
#12 ·
Since I haven't needed to accelerate like that, I haven't experienced what you are experiencing. Over 85% of our driving is around town and rarely on the freeway.

The only time I've experienced anything like your issue, is when I was in HEV, Eco modes and going up a hill starting from a full stop.

Hopefully, Hyundai can figure it out and fix it for you. If you think it's dangerous, open a complaint with the federal highway administration.
 
#17 · (Edited)
Hot, warm, cold. Doesn't matter. Ambient temperature or engine temp. The engine doesn't Rev high enough for limiter to kick on. The dealer said No diagnostic codes were present. It almost seems like there's not enough fuel being delivered and the engine doesn't accelerate hard, like I remember. The dealer said they put a scope in the gas tank but saw no signs of any visual problem. I'm going to check on changing the fuel filter if one exists.
 
#21 ·
Finally the acceleration problem is fixed! Two service technicians test drove, one with a computer connected while the other drove.
Trying to accelerate on the expressway entrance ramp is when the problem was the worst. They contacted Hyundai and only one other tech support case was reported with this problem. They reset the "adaptive values", and said specifically it is not related to the transmission, and did not reset any transmission parameters. From the service report: (Clayton) "Customer concern confirmed. Found that at high throttle input at any speeds the vehicle would fall on its face and not accelerate. Connected scan tool and found no codes stored. The engine felt as if it was either being throttle down due to another input or it could be bad gas. Monitored fuel pressures and found no problems. Reset Adaptive values and found that after doing this the problem was no longer present. Could not get the vehicle to act up at all after doing so. Had tech line case number 2018031200343." It was stated that this problem is NOT NORMAL and agreed that the vehicle was not safe to drive. If more people would have the problem diagnosed properly so it can be reported, then Hyundai may be able to create a technical service bulletin or recall to correct the problem. I put up with the issue for more than 6 months to wait for it to get worse, and was lucky I didn't get rear ended at the end of the expressway on-ramps during this time.
('16 Hyundai Sonata Plug-In Hybrid Limited)
 
#28 ·
What ive noticed is turning off blue drive on my '13 will not let the car fall on its face when i need to accelerate quickly.. TBH, i thought this problem was a product of the hybrid system and that i have to live with it, so i adapted (blue drive turned off). Unfortunately my car is out of Hyundai warranty (I have an extended one but doesnt cover hybrid side.. lame) Also i noticed it doesnt always fall on its face, other times it hets up goes with no issue when blue drive is still on. Go figure.

Sent from my SAMSUNG-SM-N910A using Tapatalk
 
#29 ·
Loss of Acceleration Problem - Now FINALLY Resolved, Replaced Fuel Pump

After two failed attempts by the dealership to fix the problem (no codes found), contacting Hyundai Customer service for additional help was the key to successful troubleshooting. The dealership initially only checked fuel quality and static fuel pressure, which were normal. Here are some notes from the service reports: "... instructed to check CAM CAM position actual and desired set points in current data. These also checked out. Performed flight records and uploaded them to our field service engineer. He found that the high pressure fuel pump was sticking in the on position causing the fuel pressure to spike above normal causing the throttle plate to close which was causing the concern. Replaced the high pressure fuel pump, reset adaptive values and reset hybrid starter generator resolver calibrations. Test drove vehicle and found that the problem was gone. The car was now accelerating as designed." :grin2:
Hopefully this will help others who are unable to analyze flight records.
I did however suspect something with the fuel filter or fuel pump, which is what I would have replaced anyway trying to guess what to fix.
Otherwise, most people would be out of luck, and just live with it, like others have mentioned in these forums.
 
#34 ·
Loss of Acceleration Problem - Now FINALLY Resolved, Replaced Fuel Pump

After two failed attempts by the dealership to fix the problem (no codes found), contacting Hyundai Customer service for additional help was the key to successful troubleshooting. The dealership initially only checked fuel quality and static fuel pressure, which were normal. Here are some notes from the service reports: "... instructed to check CAM CAM position actual and desired set points in current data. These also checked out. Performed flight records and uploaded them to our field service engineer. He found that the high pressure fuel pump was sticking in the on position causing the fuel pressure to spike above normal causing the throttle plate to close which was causing the concern. Replaced the high pressure fuel pump, reset adaptive values and reset hybrid starter generator resolver calibrations. Test drove vehicle and found that the problem was gone. The car was now accelerating as designed." :grin2:
Hopefully this will help others who are unable to analyze flight records.
I did however suspect something with the fuel filter or fuel pump, which is what I would have replaced anyway trying to guess what to fix.
Otherwise, most people would be out of luck, and just live with it, like others have mentioned in these forums.
I know this is an older post. So if you're still on here do you know if they replaced the high pressure pump on the valve cover or the one in the tank?
 
#32 ·
This also happened to me today in my 2016 Plug-in, trying to jump into another lane from a near dead stop. Yes, it feels like 1st maxes out, then nothing, nada. Scary. Any further info you're able to pass on. BTW, I just had the battery recall performed, so either that's not the problem, or the recall was not performed properly.Mike
 
#36 ·
Update on this, there was and Oil pump recall(their first try, didn't work), high press fuel pump bad, and spark plugs which were not replaced when they did the engine replacement. those last 2 fixed it for about 3 months and then it started the sputtering and stuff again and 3 months after there a different cylinder misfire.
 
#38 ·
You have something called intake manifold runners. They are flaps inside the intake that are closed until you give x amount of acceleration then they open . If they are malfunctioning it will not allow your engine to get the air it needs causing it to choke down. The actuator is probably bad and the easiest fix