Misfires on 2015 5.0 FIXED

[tsquared]

Hey everyone, just wanted to share an experience I had with my 2015 5.0 the past couple of weeks. A few weeks ago I noticed under heavy acceleration that the car started to break up and cut power. After a couple of attempts at an italian tune up the problem got progressively worse and started to finally show some codes. I was receiving misfire codes for the passenger bank (1) for cylinders 1-3-5-7 so P0300 P0301 P0303 P0305 P0307. This would only happen under a heavy load and at higher RPM. After taking it to the dealer (which I used to be a service writer at) I brought it to the foreman who checked some things and thought it might be the high pressure fuel pump on that side. They were able to get the powertrain warranty to replace the pump ($1300). No dice. The car drove slightly better but still messed up. We did a full injector service and an induction service which smoothed it out a bit at idle but the high rpm miss was still there. While doing the pump which requires the metal high pressure fuel lines to be replaced the tech had the intake manifold off and was able to scope out the Catalytic converter. There appeared to be some damage. After a lengthy call with the warranty company they agreed to replace the cat ($1700). I can happily say my car is FIXED! I had searched these forums as well as the facebook groups and found people with similar issues that had replaced plugs coils injectors whole engines ect. Just wanted to share my experience since many dont follow up with solutions! Hopefully this will help someone in the future.

 

[arcman]

Couple of questions. There's a high pressure pump on each bank? Wonder if that's normal on other V6/V8 GDI engines?

The second has me head spinning. I've created a picture from your description that I can't solve.

What kind of damage to the cat? If internal, how did he see that via the intake manifold? I can't imagine it's possible to snake a camera through the intake and exhaust valves on overlap, through the exhaust manifold and down the pipe to the cat, let alone get it back out. I'm getting up there in age but I just can't picture that working. You gotta fill us in on that one.

 

[Kraig Wilkinson]

Couple of questions. There's a high pressure pump on each bank? Wonder if that's normal on other V6/V8 GDI engines?

The second has me head spinning. I've created a picture from your description that I can't solve.

What kind of damage to the cat? If internal, how did he see that via the intake manifold? I can't imagine it's possible to snake a camera through the intake and exhaust valves on overlap, through the exhaust manifold and down the pipe to the cat, let alone get it back out. I'm getting up there in age but I just can't picture that working. You gotta fill us in on that one.

I was thinking the same . It would be physically impossible?

 

[Suburbazine]

Couple of questions. There's a high pressure pump on each bank? Wonder if that's normal on other V6/V8 GDI engines?

The second has me head spinning. I've created a picture from your description that I can't solve.

What kind of damage to the cat? If internal, how did he see that via the intake manifold? I can't imagine it's possible to snake a camera through the intake and exhaust valves on overlap, through the exhaust manifold and down the pipe to the cat, let alone get it back out. I'm getting up there in age but I just can't picture that working. You gotta fill us in on that one.

On the V8 there's a cam driven HPI pump on the back of each valve cover under a foam dome. I think the V6 is a single pump but it's been forever since I looked at it.

As far as scoping the cat, the tech most likely pulled the intake and exhaust manifolds off to scope the valves and happened to spot the top of the cat being melted over. It happens on these GDIs that throw extra fuel down the exhaust on cold start, the cat will melt from too much fuel burning on top of the honeycomb. If you've ever smelled the fuel smell on cold start, that's the gasoline burning off in the cat to reach operating temperature faster.

https://www.mdpi.com/1996-1073/10/10/1548/pdf

 

[tsquared]

Ok, hopefully you didn't bend your mind too much! It was early when I typed that. I forgot to mention the tech pulled the upstream O2 I believe that's where he scoped the top of the honeycomb. I didn't get a picture of it but I did see the printout that they had and it looked charred at the top. As for the fuel pump Suburbazine is correct there are two HP pumps, one on each bank.

 

[2015genesisNewbie]

Can someone please explain why the cat would cause misfires?

 

[Ant.Asaro]

Can someone please explain why the cat would cause misfires?

Excessive back pressure probably that's why its only under load and not at idle or during normal driving I had two gennies both of them had this misfire problem and I just never fixed it I haven't had one in two years knowing its this ill probably pick another one back up gives me an excuse to delete the cats lol