Good to know that cat replacement fixed the problem even though it may only be temporary. I am still waiting on my dealership to call me and let me know they have the cats in stock. I will let you know how my experience goes.
You guys need to explain to me how material from the CAT would get back up inside the engine. I could see cylinder walls scouring due to too much fuel washing oil off the cylinder walls or pre ignition damaging them. But nothing climbs back up the exhaust stream.Dropped my truck off with dealership last Saturday. They called me today and provided a picture of the inside of the CAT. He said they scoped the cylinders and inside the engine to make sure none of the material made its way into the engine but he said it had. They saw scoring on the cylinder walls and other damage. So they are going to have to replace the whole engine. Engine had just a touch over 5000 miles when i dropped it off. He said he has only seen this one other time on a supercharged F150 and he also said they affiliate dealership had a truck come in this week with the same issue. He is going to reach out to Roush to see if they have had reports of this happening and see if they have a fix via a tune or something else.
I had the same thought as well. In order for something to make its way back into the engine the exhaust would have to have negative pressure right? I did find an article online that said along with back pressure, steps in the exhaust system also create negative pressure waves that travel back to the cylinder. I am assuming steps meaning changes in exhaust tube diameter? it doesn't really explain that a step in the exhaust system is.
That sucks man…Dropped my truck off with dealership last Saturday. They called me today and provided a picture of the inside of the CAT. He said they scoped the cylinders and inside the engine to make sure none of the material made its way into the engine but he said it had. They saw scoring on the cylinder walls and other damage. So they are going to have to replace the whole engine. Engine had just a touch over 5000 miles when i dropped it off. He said he has only seen this one other time on a supercharged F150 and he also said they affiliate dealership had a truck come in this week with the same issue. He is going to reach out to Roush to see if they have had reports of this happening and see if they have a fix via a tune or something else.
There are high pressure waves that are created when the exhaust valves close, but there is never a reverse flow of exhaust back into the cylinders. And certainly never a flow all the way back from the CATs.
My exact thought. I can’t make sense of how that would be possible.
I am definitely going to make sure they contact Roush and ask about a new tune. I mentioned that to the service manager today. So far I feel like they are being fully transparent and listening to my thoughts about the issue as well. he said he had tried reaching out to Roush a few times today but never got a response. He thinks maybe everyone is off for Good Friday.
I hope they get you takin care of.
Yeah but the distance from our cats to the manifold makes this hard for me to believe. I am not an expert by any means.Apparently valve overlap. Kind of makes sense. if the exhaust valve is still open on the intake stroke it would suck air in from the exhaust and intake manifold.
