Hello,

About a week ago, my wife's Accord developed a constant misfire on cylinder 1. I verified the injector is working, swapped coils around, changed spark plugs, issue remained on the same cylinder. Did a compression test on all 6 and saw 180+psi on all cylinders but cylinder 1, which showed around 90. Figured a valve had gotten gummed up or had burned entirely, I took the top end apart.

Much to my dismay (after what felt like a ridiculous amount of disassembly) everything looks fine. Aside from a slightly larger amount of carbon on the #1 piston compared to the rest of the cylinders (and in the cylinder head) nothing looks out of place. Cylinder bore looks great (still has crosshatching after 170k miles), valves look fine on the face. I flipped the head upside down and filled the chamber with acetone to see if the valves or spark plug was leaking, nothing.

Does anyone know of any issues I may have missed? Are there common problems with these motors once you get to higher miles that might have caused this problem? The only other symptom was that it was burning oil, which is something it had never done before (at least not noticeably)

Thanks all.

 

Here's a picture of the rear cylinder head. I noticed there appears to be carbon or some kind of buildup beyond the edge of the combustion chamber. I wonder if whatever that is caused the headgasket to leak? It almost looks like rust somehow. Which is weird considering it's an aluminum head.

 

What did your valve lash look like? When was the last time the valves were adjusted?

With all that carbon I suspect that engine never gets fully hot and loaded. Needs more Italian tune ups!

 

The car definitely gets fully heated up. It's my wife's car so I know she doesn't romp on it much lol.
My only concern is just going through the disassembly and reassembly only to not solve the problem. Wanted to make sure I only have to do this once.

I'm not sure on the valve lash. I bought the car at 120k, but I don't know if the previous owner ever had it adjusted. They're definitely not too tight, so I don't think they're holding a valve open or anything like that.