My Veloster is throwing codes about cylinder misfires.

[Mar]

A few weeks ago I had work done for a purge leak somewhere on the top end of my engine, it was done at the Hyundai dealershipand everything has been great since. Until today, I was driving home and my engine light came on again so I pulled these codes. Any idea what's causing it or does it have to go back to the mechanic again?



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[ExtraSlow]

Mar Buddy I missed you!

[Sentry]

Check plugs is the first thing I do with any car throwing misfire codes. Apart from that, if it's turboed, check for boost leaks, make sure your fuel quality is good, blah blah. Could be a ton of things causing misfires but start there. How many km on it?

[legendboy]

Do you get these codes soon after you start from cold, rather than warm? The diagnostics screenshot looks like it was taken shortly after a cold start. If you cleared the codes after warmup and some driving will the same codes pop up?

[killramos]

[Sentry]

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Tldr: needs an engine

[Mar]

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Check plugs is the first thing I do with any car throwing misfire codes. Apart from that, if it's turboed, check for boost leaks, make sure your fuel quality is good, blah blah. Could be a ton of things causing misfires but start there. How many km on it?

It is turbo and my OBD reader was showing 15 pounds of boost consistently when on the throttle. This is also its first tank of 87 octane, it had always had 89 but Shell dropped their 89 to replace it with 93 so I had to step down to 87 which is what the manual suggests.

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Do you get these codes soon after you start from cold, rather than warm? The diagnostics screenshot looks like it was taken shortly after a cold start. If you cleared the codes after warmup and some driving will the same codes pop up?

I drove it home from work, the engine code popped up while on the way but my OBD reader won't read codes while the engine is running. After I got home, I shut off the engine, then immediately turned it back to ACC so I could read these codes. The engine isn't actually running here, I don't know why it's showing RPM.

[littledan]

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This is also its first tank of 87 octane.

/thread

[ExtraSlow]

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....
I drove it home from work, the engine code popped up while on the way but my OBD reader won't read codes while the engine is running. After I got home, I shut off the engine, then immediately turned it back to ACC so I could read these codes. The engine isn't actually running here, I don't know why it's showing RPM.

Wait, so your obd reader is also clearly broken?
Marachino_cherry_dot_gif

[ThePenIsMightier]

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Tldr: needs an engine

Engine day?
That's tomorrow.

[Mar]

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Wait, so your obd reader is also clearly broken?
Marachino_cherry_dot_gif

I've always gotten an error on my phone telling me it could damage the system if I try and read the codes while the engine is running. It suggest I turn the engine to ACC and then it doesn't give me the warning.
The reader was $11 on Amazon and I use OBD Fusion which was $7 on Google Play.

[Sentry]

Fill it with 93 or 94 and clear the codes, see if they come back.

[ExtraSlow]

Just incredible.

[legendboy]

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/thread

Try this

[Flexray]

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It is turbo and my OBD reader was showing 15 pounds of boost consistently when on the throttle. This is also its first tank of 87 octane, it had always had 89 but Shell dropped their 89 to replace it with 93 so I had to step down to 87 which is what the manual suggests.


I drove it home from work, the engine code popped up while on the way but my OBD reader won't read codes while the engine is running. After I got home, I shut off the engine, then immediately turned it back to ACC so I could read these codes. The engine isn't actually running here, I don't know why it's showing RPM.

Freeze frame is saved data from when the trouble code was set. The P0300 set at 1401rpm. If you want live data you have to go into PID's.

From the freeze frame data, I would be looking at carbon build up on the intake valves. And the dealer didn't fix the purge problem because a P0441 has set, a stuck open purge valve will cause misfires, but usually also set rich/lean codes.

I don't think the 87 fuel is the problem.

[Mar]

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Check plugs is the first thing I do with any car throwing misfire codes. Apart from that, if it's turboed, check for boost leaks, make sure your fuel quality is good, blah blah. Could be a ton of things causing misfires but start there. How many km on it?

I missed the last part, it's 16X,XXX.

[mr2mike]

Some good advice buried in here.
Can we get back to fast n furious terms. Purge valve is the BOV?

Anytime you get codes, read them, clear them and see what comes back. Don't drive the vehicle hard, see what comes up during normal, not abusive driving.
Multiple cyl misfires is almost never the plugs, inj, etc.

[firebane]

Purge valve is for emissions

Some vehicles use a BOV some use a re-circulation valve (Subarus)

But I would never run 87 in a boosted car.. shit fuel.. and can definitely cause issues.

[ThePenIsMightier]

It was noticeably colder today.
Frozen battery.

[SJW]

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It was noticeably colder today.
Frozen battery.

Or……….somebody’s got a case of the Hyundais