• Welcome to N-cars.net - the largest Hyundai N car forum. Check out the model specific sections below and scroll down for country specific forums. Check out the i30 N Bible Here!

Crosspost - 2019 Veloster N misfire/fuel issue

Cygnus X-1

Well-Known Member
Not happening on mine. Almost 2000 miles now. I will say that this could be an issue with the electrical system, due to poor ground quality.

This was a huge problem on the first gen VTs, causing all kinds of misfiring issues and ignition coil problems. What we did was clean the paint and primer off of the main (engine bay) chassis grounding points so bare metal was exposed.

This improves the electrical connections by lowering resistance and voltage drop. Use dielectric or any other conductive grease to seal the exposed metal to grounding plate connections.

Before doing this, use a multimeter to test the electrical resistance of the main chassis grounding points and you should see upwards of 6-12 ohms. After cleaning up each grounding point, test with the multimeter again and you should see a substantial reduction in resistance. They should be around 1.0 ohms or lower each.

Ignition coils rely on the chassis ground on the RH side strut tower (passenger side in LH drive vehicles), so test and clean that one first. The one on the LH side (connected to the negative battery terminal) is behind the ECM, so do that one later when you have more time. There are others scattered around the engine bay (including two right next to the ECM).

Once you finish, the engine should start easier and hopefully your misfiring issues will be cured.

If it does not fix the issue, then you can diagnose the HPFP with a dealer’s help.
Last edited:
I'd like to let everyone know that after I took two road trips (dallas->houston->dallas->san antonio->dallas) and now have 2250 miles, the issue appears to have gone away. No idea if it will come back or not.

When it was happening, one thing that seemed to help a bit was to start the car, let it idle for 10 seconds, turn it off for 5 seconds, then start it again and drive, it happened less when I did that.

and no, never any check engine lights or codes that the dealer could pull
No lights showing is going to make this difficult. Just picked mine up and am around 350 miles, thought it seemed sluggish the last couple of days. Then again it's been around fifty degrees here. Hoping it's not going to be an issue....
yeah mine sometimes feels sluggish and sometimes feels quick, at first I thought it was just because of air temperature, but it doesn't actually seem related. Can't put my finger on it
I'm first going to have to ask, what modifications have you done to the Veloster N?

I can see by your user name you might be utilizing a Performance Chip possibly, might be wrong but if you are, remove it and throw it in the trash or send it back and get your money back. They are junk and a scam even proven by dyno's.

Second, what fuel are you running in the tank? Less than 91 is a big non-starter.

What mode are you running the car in?
Last edited:


Well-Known Member
@R Veloster N what’s a ‘Performance chip’ if you don’t mind me asking?

To the OP, search the forum as a lot of us early I30N adopters had an issue with our ECU’s (requiring a replacement) and fuel pump. I don’t believe the VN suffered from this but who knows....

My I30N still has the very occasional hesitation on start up but no actual loss of power after I had my new ECU.

These turbo charged engines don’t like temperature extremes, that’s for sure. And it’s something I first noticed in my Kia Pro Ceed GT - she didn’t like the cold!

Of course, if you are concerned there’s perhaps an underlying issue then I’d get the car booked in.
Stock, never heard of "performance chip", 93, N mode
Sounds like you've gotten some bad fuel (water in the fuel). Run some dry gas or FI cleaner thru the system ie, Chevron Techron, BG Fuel Cleaner etc.

Does it respond similarly in other modes; normal, eco, sport?

Has your N ever gone into limp mode during these issues?

Bad fuel will cause it to go into limp mode to stop any damage occurring to the motor.

Engine check light ever come on during these events?

Also, disconnect the battery for 30 minutes. This will cause the ECU reset to OEM setting. It will also cancel the limp mode. See if this doesn't solve the issue.

@R Veloster N what’s a ‘Performance chip’ if you don’t mind me asking?
A Performance Chip is a plug in ODB II chip that is suppose to make performance tuning changes to the ECU. https://www.chipyourcar.com/ This is just one of them. They're a scam and proven not to work by dyno. Many times, causing more problems to the motor.
Last edited:
No problem, you're welcome and if you see one like it, don't be persuaded to buy it either.

Generally it's the simplest problem which causes such issues. Needs to be diagnosis correctly. Start with the simplest first and then go forward. It will saves time, effort and money.