Alldata says firing order is 1-2-3-4-5-6.
2 and 3 are adjacent to each other in the firing order so is it possible that the misfire counter is not accurate?
Ideally, I think a cranking vacuum waveform and in-cylinder waveforms could be helpful here.
2008 Toyota Camry V6 P0303
- Thread starter The Critic
- Start date
2 and 3 are adjacent to each other in the firing order so is it possible that the misfire counter is not accurate?
Ideally, I think a cranking vacuum waveform and in-cylinder waveforms could be helpful here.
That was what I was getting at. Because the issue happens at such a high RPM the ECM may be picking an adjacent cylinder in the firing order as the problem because it happens too quickly to accurately pinpoint. I have seen it before. Not necessarily on a Toyota though.
I remember reading that sometimes that misfire code can be off a cylinder. Ran into this many years ago on my 99 Avalon. Maybe your problem is cylinder #2.
Cylinder #3 intake valve spring broke.
I do not understand how the car runs fine under normal driving.
Or why the valve did not drop into the combustion chamber.
132K
I've ran across this on 3 valve Fords when one of the Intake Followers falls off from a needle bearing failure....You still have the other Intake Valve actuating letting just enough air in to run okay at lower engine loads.
Seen many a broken valve spring NOT drop a valve.....Long as the Keepers & Retainer stay in place.
Oddly enough, the keeper and retainer were not in place.
Buy a lottery ticket....Cause you're one lucky cat!!
In all seriousness.....The Valve Guide Seal could in theory keep the valve from dropping, But I have yet to experience such.
In all seriousness.....The Valve Guide Seal could in theory keep the valve from dropping, But I have yet to experience such.
OVERKILL
$100 Site Donor 2021
Well, that'd do it!
I second the motion buying a lottery ticket! Not sure how that valve didn’t just fall out and destroy that cylinder since the keepers weren’t even holding the valve in place. I would still make sure that valve did not get damaged, make sure it moves up and down smoothly. Nice job. Still strange about your findings on #2 through…
Slowclap for the accuracy of misfire monitors these days
Buy a lottery ticket, you earned it
Let us know how it runs after repair
Buy a lottery ticket, you earned it
Let us know how it runs after repair
JHZR2
Staff member
Im assuming this is a DOHC VVT engine, so it seems that it could run "good enough" until it really needs to breathe, which is >5000 RPM or so(?).
I guess there is enough upward force on the valve during some strokes, and compression to press it hard up, that it wont fall. Friction I guess?
Seems very lucky.
I was taught that valve spring "float" when it is past the maximum rpm it is designed for. Not sure if spring breaking is going to pop the spring "seat" out of the valve but assuming everything else is fine the spring itself may have enough length to hold up to the closing position at lowish rpm, then when it is higher rpm it won't have enough strength to push it back up fast enough, and it "float", causing misfire.
Did you find all the other pieces like the seat and clip holding on the valve still? or fell off and scatter over the head / block?
Maybe the compression has enough force to push the valve back up and it just open wide during the intake stroke, but it is a miracle it didn't grind up metal pieces and send it all over the engine.
JHZR2
Staff member
The amount of vacuum that could pull it down is less than the amount of pressure due to compression and especially combustion. I guess there's enough friction with the valve guides and whatnot to prevent it getting sucked downward.
Preliminary order. Coolant, RTV, A/C Recharge and oil and filter are not included on that list.
Repair time is 24.6 hours plus the few hours I have already spent.
Are you replacing all 6 cylinders' valve spring and related parts? Also all the oil pump related parts too?
All 24 springs are getting replaced. For the spring that broke, I am also replacing the stem cap, keeper(s) and roller arm.
Belt tensioner is getting replaced while the car is out. It is normally very difficult to access the belt tensioner.
The partial rubber VVT oil line (for bank 1), spark plugs and 3 broken ignition coil connectors will be replaced while the engine is out.
Everything else is an o-ring or gasket that must be replaced since the components are being disassembled.
Clearly you're doing the repair the right way. Do you think it's possible for someone that just wanted to get it back on the road to pull the one cam and just replace the broken spring and rocker arm?
