2009 Acura MDX - Have a misfire? Adjust the valves

Strong misfire problem. Car has 130000kms.
Solution was to adjust the valves.

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Fixed our Honda Fit’s long and mysterious misfire issues as well. Good advice.

What’s the code?


If this involved an exhaust valve being tight and if the problem went on for 50 or so miles you are not out of the woods yet.

Hot exhaust gas passing through the valve port can cause microscopic pitting of the valve face and valve seat as the heat in the exhaust valve is not being dissipated into the valve seat due to the exhaust valve not closing.
Takes a magnifying glass sometimes to see this with the head off.

Eventually that pitting becomes more serious and a valve job along with new valves may be required. How long that may be depends upon various factors.

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I had a similar experience with a low mileage 2002 Miata. A long term puzzle finally solved. At the rate this car rolls up mileage it will be 10 years before a valve job will be needed and maybe by then I won’t feel it’s my job to do it. That’ll be a relief.

The Japanese OHC engines with rocker arms and non-hydraulic lifters need valve adjustment every 50,000 km or so, period.
I owned 4 Hondas, 1975-1988, and valve adjustment was one of the more satisfying DIY tasks.
Also did it for friend and family Honda, Toyota, Datsun etc.

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So, it was when they became Nissan when the valve job became a nightmare with getting your camshafts off?
From my own experience, getting valves adjusted in VQ40DE engine was not gratifying experience at all with half of the top end to be disassembled just to get there.
If timing chains did not eat the plastic guides and valve seals were not getting old, I would probably just raised my radio volume up and forgot about it.

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Adjusting valves can sometimes solve mysterious emissions compliance problems too. If the valve clearance for one cylinder is incorrect, but the others are ok, the engine computer has no way to compensate for this. The overall air/fuel mixture ratio will be incorrect, which will adversely affect emissions.

All I’m saying is they were Datsuns back in the day when I did that.
The Datsun (510 IIRC) had the same screw and locknut arrangement as Hondas.
No cam removal.

That 02 Miata used sized inserts, not screw and locknuts. I was able to loosen the camshaft caps enough to get space between the cam lobes and the insert, extract the insert with a magnet on a stick, and slide in the new one. It was a big job, fussy, and I replaced the timing belt, etc., at the same time. Toyota inserts were exactly the same as Mazda, available in more thicknesses, and cheaper.

Every 3 years/36,000 miles or so I have adjusted them on my 1999 Honda Civic. Always a few have needed it. The car runs great at 198,000+ miles.