Engine misfire after using Racechip mod

[hwhorf]

Hello,

I have a 2018 Genesis G80 with 22k miles on it. I have been using the Racechip for around 1k miles and I recently ran into a problem. I felt a big misfire and the check engine light turned on. The performance of the car is absolutely gone now. It is jerky and shaky when accelerating. I unplugged the Racechip and took it to a dealership in CA. Unware of the performance upgrade, they said the engine misfire was due to low voltage. They cleared the codes and sent me on my way. The engine misfired again and the check engine light came back on.

I still have warranty on my vehicle. They told me they could not check all the spark plugs because the engine misfire was due to low voltage and not current so it wouldn't be covered under warranty. Should this be covered under warranty or is that BS? I had a comma2 dash cam plugged into the obd port and my rep said the low voltage misfires are because of that. Never had problems with this device before and I don't think that's the issue. He said if I want them to check all sparks, I will have to pay for man hours and it would take them 6 hours??

How should I proceed? Should I ditch the dealership and have some other place take a look at it? Does anyone know what might be the issue? I am using stock NGK sparks.

Thanks!

 

[Stocks2k]

Not the same engine but my son's 2018 Elantra GT Sport was having misfire codes and the dealership replaced all 4 coil packs. They said it was a known issue and was covered under warranty. It may be worth looking into. Switch the coil packs and see if you get a different cylinder misfiring.

 

[John M]

You should never attempt raised boost on stock plugs. Reputable tuners all tell you what to use with their product.

If it's still misfiring it means you may have broken off a piece of plug. That could mean piston or valve damage. You won't know until you pull the plugs and look at them. Misfire errors should tell you which cylinder(s) it occurred in so you'll know where to start looking.

You are correct though - nothing plugged into the OBD port is going to affect the voltage available to the coilpacks!

 

[hwhorf]

You should never attempt raised boost on stock plugs. Reputable tuners all tell you what to use with their product.

If it's still misfiring it means you may have broken off a piece of plug. That could mean piston or valve damage. You won't know until you pull the plugs and look at them. Misfire errors should tell you which cylinder(s) it occurred in so you'll know where to start looking.

You are correct though - nothing plugged into the OBD port is going to affect the voltage available to the coilpacks!

They said a low voltage code doesn't specify which cylinder. They looked at the front two plugs and said those were fine. Looking at all the plugs wouldn't be covered under warranty because of type of code it threw. I am going to take the dash cam I have plugged into my obd port out and take it to another Genesis dealership to see if they'll pull all the plugs and fix the piston/valve damage under warranty. Racechip doesn't leave behind a trace.

If they don't cover it under warranty do you how much it would cost to get a new piston? How much would it cost to replace the valve?

Thank you

 

[BadTrainDriver]

First of all, you messed up by running any performance tune with stock spark plugs. That's a huge no no. If you'd done some research, you'd fine that the stock plugs are sometimes problematic at stock power levels. Strike one.

Now, you're trying to be deceitful with the dealership. Strike two.

What you need to do now is remove/inspect/and replace all spark plugs. If you're unable to do this yourself, find someone who can. With the proper tools, it's a 1.5 hour job for the first time, and about 30 minutes the second time, after finding what tools work best where.

If you're lucky, you just cracked a plug, and a good set of plugs will fix your problem. I recommend HKS.

If you unlucky, you damaged a piston or valve...but I'm willing to bet it's just a plug issue.

Oh, and as an FYI, when you take your car to a dealership and they perform any inspection or service, there is a record of that. Go to another dealership, they'll see that record.

 

[hwhorf]

First of all, you messed up by running any performance tune with stock spark plugs. That's a huge no no. If you'd done some research, you'd fine that the stock plugs are sometimes problematic at stock power levels. Strike one.

Now, you're trying to be deceitful with the dealership. Strike two.

What you need to do now is remove/inspect/and replace all spark plugs. If you're unable to do this yourself, find someone who can. With the proper tools, it's a 1.5 hour job for the first time, and about 30 minutes the second time, after finding what tools work best where.

If you're lucky, you just cracked a plug, and a good set of plugs will fix your problem. I recommend HKS.

If you unlucky, you damaged a piston or valve...but I'm willing to bet it's just a plug issue.

Oh, and as an FYI, when you take your car to a dealership and they perform any inspection or service, there is a record of that. Go to another dealership, they'll see that record.

Thanks for the info. Being deceitful with a dealership though... lol good one

 

[BadTrainDriver]

Thanks for the info. Being deceitful with a dealership though... lol good one

Well, I mean you were trying to be. No real way to deny it.

 

[hwhorf]

Well, I mean you were trying to be. No real way to deny it.

True and I learned my lesson.

Do you know what would be more expensive to repair or replace? A piston or valve damage?

Does anyone know if it would probably be fiiine driving the car a 100 more miles?

 

[BadTrainDriver]

True and I learned my lesson.

Do you know what would be more expensive to repair or replace? A piston or valve damage?

Does anyone know if it would probably be fiiine driving the car a 100 more miles?

Drive it as little as possible with the least amount of boost. A piston would be much more expensive to replace than a valve.

Can you replace the plugs yourself, or know someone who can?

 

[John M]

Have someone else read the CEL code. Even an auto parts place like Advance Auto will usually do that for free. The specific code is far more useful for we "remote mechanics" than secondhand interpretation by the service department.

I'd have someone inspect the plugs. If you're lucky the detonation (knock) opened the gap and new plug(s) could take care of it. If a piece of a plug is missing then we move on to engine damage.

Dealers don't usually get into actual engine repair. At best they'd offer to sell you a factory short block. On my Sonata 2.0T (free engine replacement under recall) that would have been around $4k with labor. The v6 TT could easily approach double that amount - if they can get them.

______________________________

Help support this site so it can continue supporting you!