2012 Sonata Tip-In

[GenesisGuy70]

Morning BITOG

Defendant: 2012 Sonata 2.4L
Plaintiff: My Sister
Complaint: Aggressive Throttle Tip-In

Presiding Judge: The Honorable Backyard DIY’er

Defendant is confirmed by myself to have excessive throttle tip-in. For a 2012 Sonata 2.4L this thing bolts off the line and will smoke those front tires like a hippie at Woodstock. I drive a Genesis G70 AWD and it doesn’t dart of the line like this Sonata. You just BARELY touch that pedal, like just the weight of your foot, and BAM that thing takes off. I attempted to do a throttle body relearn by following a process I used on my Ford. Disconnecting both posts and connecting them to drain ECU capacitors. Noteable change in shift quality afterwards so confirms that shift points had been reset, smoothed out as it relearned values. No change to throttle though.
Any ideas? Vacuum leaks checked for and nothing. Filter is dirty but not awful. Runs like a top otherwise. 153,000miles.

 

[vivaUkraine]

Is RPM gain normal or do they rise as if gas pedal pushed out completely?

 

[mk378]

Have you cleaned the throttle body? This is the common symptom of the throttle plate sticking to gunk on the sides of the throttle body then suddenly jumping free, causing an abrupt acceleration off of idle.

Remove throttle body and clean it from the back side, that is where all the dirt will be.

 

[JohnnyG]

I agree with the throttle body cleaning, very common issue. My friend also has a Kia from that era and the throttle spring is way too stiff. It also makes the car jump off the line and makes it hard to drive smoothly. Nobody wants to ride with her because of the jerky throttle going down the road. I don't know if there is a proper fix for that, she just accepts it as normal!

 

[nicholas]

We had a 2010 santa fe that had this also - - - - a few years later the dealer did a software change, tsb, and it really dulled it down.
almost too much.

 

[GenesisGuy70]

Update: Throttle body was disgusting. Had a thick oily coating around the plate. Was definitely getting hung up. I cleaned it out spotless and reinstalled. Fired it up and it ran like garbage for a while. Eventually got a check engine light. It was like it had run so poorly for so long it didn't know how to run right! So as a Hail Mary and not feeling like doing anymore detective work, I disconnected the pos and neg again and connected them via a simple wire and let it sit. Turned it on and let the gauges prove out and then turned it off. Waited 10 seconds and fired it up. Check engine light was gone and the overkill acceleration disappeared. It's ran perfectly ever since. Could use a new set of plugs though, those will be here in a few days. Saved $10 on 4 of them from Amazon Warehouse. Assuming someone bought them and they were the wrong ones and returned them and I picked up the savings.

 

[Kurtatron]

That confarbled new tech fixes things that ain't broke. Give me drive by cable throttle bodies all day! Glad you exorcised the electrical demons.

 

[mk378]

The sticky throttle plate affects old-fashioned mechanically linked throttles as well. There the driver can feel the pedal sticking then breaking free, making the diagnosis more obvious. But the effect is the same, it will be difficult to drive in stop and go traffic without lurching forward.

 

[AutoMechanic]

Glad you got it figured out somehow lol. I personally wouldn’t have gotten the plugs from Amazon but that’s just me.