I suspect you need a valve adjustment. I went through the same circus on my ‘03 when I bought it with 305k, adjusting the valves solved all the problems.

Your symptoms also point to valves - the exhaust valves on the first Gen Pilots slowly tighten over time. When the motor is cold the exhaust valves are more open which allows gas combustion to occur ‘more normal’.

As the motor heats up, the metal gets hot and the exhaust valves tighten, in effect choking the combustion chambers. The higher the engine revs the larger negative effective on combustion.

I performed the first adjustment on my vehicle and 23/24 valves were out of spec; all 12 exhaust valves were tight and 11/12 intake valves were loose.

 

the exhaust valves on the first Gen Pilots slowly tighten over time.

This is actually true for a lot more than just those Pilots. The whole J series especially.

And with tight exhaust valves, you will eventually burn a valve, turning what could have been a relatively cheap valve adjustment job into a full valve job.

 

Thanks for the replies. Valve adjustment - did you do it yourself? How much time to do it? Tools needed? Is there a procedural list (other than a youtube video)? I'm going to ask about the cost to have this done by my local mechanic, as well. It's almost shameful that a company like Honda would require valve adjustments, especially on an OHC design. Reminds me of the Y block engines from the 1950s with solid lifters, my Dad had to adjust the valves every couple of years. For manufacturers other than Honda, technology eliminated the need for valve adjustment.

 

The J series design dates back to 1995.

Valve adjustment on the J series is not necessarily the simplest task, especially if you have no experience adjusting valves on an engine. If you have no experience doing so, I would advise against a DIY job, as this is not the engine to be doing your first valve adjustment on. If you get it wrong, you won't know until everything is put back together, and then to correct it you'll have to go back in there, which means taking the intake manifold and all that back off to get the valve covers off, and you also have to wait for the engine to cool back down since valves are adjusted stone cold on these. In other words, this is something you want to be sure you get right on the first try, and it's harder to do that without experience. It's not as quick and easy like it is on the 4 cylinder engines.

 

Search the forum, lots of threads and advice on here for valve adjustment.

In addition to your normal socket set, you’ll need a set of offset/bent clearance (feeler) guides and a few metric wrenches. They make a special tool to tighten the valve but it’s useless on more than half the valves and you’ll end up using a wrench and screwdriver anyway. You’ll need a 3/8 torque wrench - if you don’t have one, go to Harbor Freight and buy the Pittsburgh they sell, it works fine for this. Most nuts/bolts are 10 or 12 mm. There are a few threads with detailed tools and parts lists, again just search this forum.

You’ll need new valve cover gaskets and tube seals, spend the extra $20 and buy the Honda gasket set. The aftermarket FelPro are a little cheaper but more flimsy and have failed early for several of us that wrench (a lot) on cars, suggesting it’s a FelPro issue and not mechanics error.

It takes most of us with experience about 4-6 hrs start to finish the job, but I think that’s also because we reserve this job for a weekend and take our time. This also usually includes super cleaning the valve covers (some even paint the covers) soaking and super cleaning the intake chamber, and in general just taking time to do it right the first time.

The rear bank is sucky and your back will hate you from being bent over at odd angles, so I opted to do that one first. I took a break after each cylinder to work on the valve covers and intake, and it really wasn’t that bad, but the front bank felt like cake after doing the rear first.

This is not a difficult job but you need to develop the feel for the correct amount of ‘drag’ on the feeler gauges. I suggest that anyone place the feeler gauge in there then intentionally under and over tighten the first valve you work on until you’ll find the sweet spot pretty easy. More clearance (less drag) within spec is better than too much drag, which means the lash is tight.

FYI, Honda recommends checking the valve lash every 100k, so you’re just past the 3rd check, or way way past due.

 

I agree with @ckeator . If you are mechanically inclined, go for it! If you have plenty of cash around then pay someone else. I did my first ever on my 2005 exl. Just Go Slow & Triple check. Also, remove the hood latch that will be sticking into your chest as you do the rear bank, use a moving blanket for padding and get a some sort of step up to stand on. I used a drywall scaffold about 20” tall. I’m 5’-11” 198. Hope that helps!

 

A few notes with the screw/nut you have to adjust. Break their bond before making adjustments. When you go to tighten the nut you will turn the screw and lose your adjustment. Just hold the screw in place and twist the nut back and forth. Use a socket and a thin screwdriver. Put the socket on the nut and the hole on the socket stick the screw driver down to make your adjustment. Make sure to torque down your nut before you go back through one more round making sure everything is set correctly. When you tighten the nut keep your feeler gauge in place so that it keeps the screw from tightening. Take a feeler gauge that is 3 times larger in size and ensure you can't get it go in. 1 size larger should go in with a bit more drag, and 2 sizes larger should go in with a considerable amount of effort.
Exhaust tighten over time, and they are the ones that damage your valves. It is important to not overtighten your exhaust valves. Intake are more forgiving, but exhaust valves are not. Loose is safer, but could cost you performance, so you don't want to go too loose.
Intake loosen over time. These you don't want to go too loose since they will continue to loosen over time. There is no damage from loose valves, but you loose performance as a result. There is a sweet spot, and that is the middle of the spec which you will find on a sticker on the inside of your hood. Don't get your intake and exhaust mixed up since they flip from the front and the back.
Don't for get to turn your engine to each cylinder. You can loosen your spark plugs to help, and would be a good time to look at them and see how they are wearing. Pay attention to if they are loose or not and make sure they are denso or NGK only. If they are anything else replace from a reputable source. Ebay is not a reputable source.
Once you are done, and have torqued down every nut (torque them all down in a row so you verify you didn't forget any), go back over every one again to verify they are good. Repeat if you had to make adjustments.
Check that you need to make an adjustment before you crack open the nuts. If they don't need to be adjusted, don't waste your time adjusting them.
This is a great time to do other maintenance. Clean EGR system it is a circular system, and the top of the intake is attached to the egr valve through channels and ports. You need to clean the ports that go from the top of the intake to the bottom of the EGR valve, and the channels on top of the intake and the tiny holes going into the intake. Replace the egr valve gasket.
Clean the throttle body without moving the butterfly valve. Make sure it is dry or it will cause the butterfly valve to stick or clog again. Replace the throttle body gasket
Check the hose between the throttle body and the air filter
If your valve cover is leaking get a valve cover gasket kit with the tube seals and gaskets for each cover. If it is not leaking when you take off the covers bend the gaskets and check for pliability. You don't want to see any cracking, or have it feel stiff. Check the spark plug tube seals as well. If any of these feel stiff replace them, if they are pliable re-use them, but it's cheap enough, just replace it. Use hondabond or RTV on the cracks, and remove the old before re-installing cover. Put on the head and not the cover. Do not use on gasket. Make sure it stays in place by turning it upside down and the gasket should not fall out. When installing new tube seals walk it around the tube. Make sure it goes around the tube and doesn't get pinched between the valve cover and tube or you will be replacing them again.
If you only have straight feeler gauges you can bend them 45 degrees not 90 degrees, but 45 degrees about an inch up. I like to put tape around the other end for something to grab onto.
You can turn the engine over by turning on the camshaft bolt in the front. It is 17 mm I believe, and you will need to loosen the spark plugs to do this. Turn clockwise, do not turn counter clockwise. There is a small hole in the front timing cover that is covered with a plug you have to remove. It's not hard to miss, and you can see the firing number as you turn it. There will be a mark that lines up. The viewing angle sucks, so you will want to either use your phone and a light or mirror to see it otherwise you won't see it.
123 rear head cylinder order
456 front head cylinder order looking at it from the front of the vehicle
Whatever number you see in the timing cover hole is the cylinder you should work on. They don't go in order, so just pay attention to what number you are on.
replace your pcv valve at this time as well. Remove it before you start the job in case you have to fish it out of the valve cover. Careful removing it, as it can snap. Use two flat head screw drivers, and pry from opposite sides outward. Don't pry on the bolt hole, that gives too much torque on the outside and will snap it inside the valve cover. Unless you have 03-04 engine. It is easier to replace. This is for 05+
Clean around the valve covers before opening them up. You don't want debris getting into the valvetrain. Cover the intake ports as well, either stuff with paper towels or tape over them. Just remember to remove once you are finished.

 

A few notes with the screw/nut you have to adjust. Break their bond before making adjustments. When you go to tighten the nut you will turn the screw and lose your adjustment. Just hold the screw in place and twist the nut back and forth. Use a socket and a thin screwdriver. Put the socket on the nut and the hole on the socket stick the screw driver down to make your adjustment. Make sure to torque down your nut before you go back through one more round making sure everything is set correctly. When you tighten the nut keep your feeler gauge in place so that it keeps the screw from tightening. Take a feeler gauge that is 3 times larger in size and ensure you can't get it go in. 1 size larger should go in with a bit more drag, and 2 sizes larger should go in with a considerable amount of effort.
Exhaust tighten over time, and they are the ones that damage your valves. It is important to not overtighten your exhaust valves. Intake are more forgiving, but exhaust valves are not. Loose is safer, but could cost you performance, so you don't want to go too loose.
Intake loosen over time. These you don't want to go too loose since they will continue to loosen over time. There is no damage from loose valves, but you loose performance as a result. There is a sweet spot, and that is the middle of the spec which you will find on a sticker on the inside of your hood. Don't get your intake and exhaust mixed up since they flip from the front and the back.
Don't for get to turn your engine to each cylinder. You can loosen your spark plugs to help, and would be a good time to look at them and see how they are wearing. Pay attention to if they are loose or not and make sure they are denso or NGK only. If they are anything else replace from a reputable source. Ebay is not a reputable source.
Once you are done, and have torqued down every nut (torque them all down in a row so you verify you didn't forget any), go back over every one again to verify they are good. Repeat if you had to make adjustments.
Check that you need to make an adjustment before you crack open the nuts. If they don't need to be adjusted, don't waste your time adjusting them.
This is a great time to do other maintenance. Clean EGR system it is a circular system, and the top of the intake is attached to the egr valve through channels and ports. You need to clean the ports that go from the top of the intake to the bottom of the EGR valve, and the channels on top of the intake and the tiny holes going into the intake. Replace the egr valve gasket.
Clean the throttle body without moving the butterfly valve. Make sure it is dry or it will cause the butterfly valve to stick or clog again. Replace the throttle body gasket
Check the hose between the throttle body and the air filter
If your valve cover is leaking get a valve cover gasket kit with the tube seals and gaskets for each cover. If it is not leaking when you take off the covers bend the gaskets and check for pliability. You don't want to see any cracking, or have it feel stiff. Check the spark plug tube seals as well. If any of these feel stiff replace them, if they are pliable re-use them, but it's cheap enough, just replace it. Use hondabond or RTV on the cracks, and remove the old before re-installing cover. Put on the head and not the cover. Do not use on gasket. Make sure it stays in place by turning it upside down and the gasket should not fall out. When installing new tube seals walk it around the tube. Make sure it goes around the tube and doesn't get pinched between the valve cover and tube or you will be replacing them again.
If you only have straight feeler gauges you can bend them 45 degrees not 90 degrees, but 45 degrees about an inch up. I like to put tape around the other end for something to grab onto.
You can turn the engine over by turning on the camshaft bolt in the front. It is 17 mm I believe, and you will need to loosen the spark plugs to do this. Turn clockwise, do not turn counter clockwise. There is a small hole in the front timing cover that is covered with a plug you have to remove. It's not hard to miss, and you can see the firing number as you turn it. There will be a mark that lines up. The viewing angle sucks, so you will want to either use your phone and a light or mirror to see it otherwise you won't see it.
123 rear head cylinder order
456 front head cylinder order looking at it from the front of the vehicle
Whatever number you see in the timing cover hole is the cylinder you should work on. They don't go in order, so just pay attention to what number you are on.
replace your pcv valve at this time as well. Remove it before you start the job in case you have to fish it out of the valve cover. Careful removing it, as it can snap. Use two flat head screw drivers, and pry from opposite sides outward. Don't pry on the bolt hole, that gives too much torque on the outside and will snap it inside the valve cover. Unless you have 03-04 engine. It is easier to replace. This is for 05+
Clean around the valve covers before opening them up. You don't want debris getting into the valvetrain. Cover the intake ports as well, either stuff with paper towels or tape over them. Just remember to remove once you are finished.

Wow!! Awesome write up😊👍👍.
Thank you for taking the time and sharing

 

Can somebody “Sticky” or save @royalbiggster ’s post #8 to Valve Adjustment Technique/ Information in Maintenance section or where ever is best place to find easily?

 

The valves were adjusted, so far that has cured the intermittent misfire (P1399) issue, but the P1492 (EGR) code came up right away. Luckily the valve adjustment isn't needed for another 100K, and I should be long dead by then.

 

P1492 or P1491?

 

P1491

 

I would make this and see if you have a leak in your egr system. Might as well check your entire system, intake, fuel tank, vacuum, exhaust, etc...