thanks.. i did figure out it is the knock sensor for sure..

120 dollar replacement


aftermarket garbage is within 10 dollars of a genuine part.. so i'm not even going to waste my time with an aftermarket piece and risk it failing.


calling machine shop(s) tomorrow to get prices and timeframes on getting my head rebuilt. i found a rebuilt one online, but the guy was unsure how many miles exactly are on the cam journals and cam caps.. so i'm not sure i want to spend 300+ on a head that might have more miles on the cam and cam caps than mine does.


unless i get quoted for a rebuild at some insane price... then i might consider it.

 

small update.

cylinder head is on it's way to being completed.

waiting on a replacement exhaust valve to come.. will be here tomorrow morning..

anyway, i got to see the head all torn apart.. and check out the wear on the cam journals/caps. and the rocker assembly... i'm completely impressed by the minimal amount of wear the head has for having 96000 miles on it... it's in FANTASTIC shape as far as moving mechanics goes. there is minimal wear on the cam journals/caps, the rocker assembly.. and valve stems/guides.

i spent some time and 2 full cans of brake parts cleaner and a brass bristle brush and cleaned and scrubbed the tops of my pistons until they were down to metal. there was so much carbon build up on them i couldn't live with putting it back together like that.

also. cylinder 3 had significantly more carbon on the piston, and based on the intake manifold ports, it has the most flow of oil from the PCV system.. considering the placement of the PCV valve inlet to the intake manifold.. i can see why..

so.. i'm going to fab up a catch can to trap the oil before it gets to my cylinders...


OH! while i was at the machine shop.. i got a souvenir, check it out.

 

Well, that certainly explains the lack of compression in that cylinder...

 

good news!!! i got the car all back together now.. new timing/balance belts and tensioners as well as a new water pump.. new camshaft oil seal, and new crankshaft oil seal (i was going to attempt the balance shaft seal but there isn't much room to work with and it's in great shape).

anyway, the rebuilt head had all 16 valve seats machines, 3 angle valve job performed on all 16 valves (yes including the brand new one) the valves are ground to be VERY round and true, the equipment the shop has is geared up for high performance race engines so they are VERY accurate.. all 16 valve stem seals were replaced, and 2 screw tappets that were worn abnormally compared to the rest.


i adjusted the valve clearance myself with high precision Starrett flat stock. valves were set at .012 inches on the exhaust side and .010 on the intake side with the head on the bench and no oil in it so i got a real feel for the actual clearance.

fresh gaskets on the intake/exhaust manifolds.. cleaned the entire intake out as much as i could(had it all apart out of the car and used 2 cans of brake cleaner on it with some medium scrubbing). filled the car with fresh oil, a new filter, and genuine Honda coolant(which is priced similar to prestone actually.. but it has additives for the aluminum engines in it and is made with de-ionized/distilled water from start to finish.. so there's no chance of mineral build up).

and basically.. it runs FANTASTIC absolutely fantastic.. totally different car pretty much.. the valvetrain is really quiet now. under load just cruising on the highway you can't hear the engine over the road noise.. it's just an absolutely different car now.. a real pleasure to drive

based on the way the engine reacts to short throttle blips from idle sitting still and cold/warm start-ups.. this problem seems to have been occurring since before i bought the car. if you would give it a short blip after it was warmed up.. it would rev up to about 2k and then come back down to near stalling before it would correct itself. now it corrects itself on the return trip down and steadies off at around 750ish... right were it should be.

some other interesting things to see as time goes on.. oil consumption (maybe the valve stem seals were really bad, or maybe it is all in the PCV system) and gas mileage.. the gas mileage slowly, steadily declined since i bought the car.. and even after running injector/fuel system cleaner and attempting to clean the cylinders with various carbon remover solvents that were recommended by various people on various forums the fuel mileage never improved.. after the trip that this became a really evident problem on.. i noticed an immediate drop in power, and a major decrease in highway fuel economy. the car now has freshly cleaned pistons and combustion chambers.. and i'm going to add a catch can in the PCV system to minimized the oil being burned and help prevent future carbon build up.


i'm betting my mileage goes up to better than it was when i bought the car. i was averaging 28 in the city.. and that's not driving as conservatively as i could. towards the day this failure happened, it slowly declined to 25ish in the city.


anyway.. i'm done writing now.

later,

Moddage

 

Slow decline in MPG can be due to that hole getting bigger over time with erosion.

This whole process also reminds us to check compression when we're trying to figure out what's happening.

 

yeah.. that's why I'm figuring my mileage will increase.. also, ordered an oil catch can for it too. trying to keep my intake/cylinders as clean as possible.


that's one thing i didn't think of.. i should check my compression now and see if it increased in any of the 3 that were "normal" and also verify that no. 2 is back to where it should be... i know for a fact it runs strong and pretty hard for a 4 banger. i just tested out VTEC from 3rd to 5th on the highway... and it pulls like it should. possibly better than it ever has since i've owned the car.

the only things i really want to do to the car now are strut tower braces(front and rear) a short shifter, and maybe a better intake tube setup.. the stock one is pretty restrictive.

 

Since you didn't do anything to the cylinder walls & piston rings, I'd expect the other 3 would kinda remain the same. Obviously, #2 had better be MUCH improved.

Go ahead & measure compression; it can't hurt. If you had done the rings, I'd expect it to be a bit worse now, with an improvement over a few thousand miles.

 

I was wondering what causes the burnt valve issue? I had the exact same issue , but as time went by after my head replacement it done it again? So would I be right to assume it could be my injectors?