In the past couple of months my intermittent weak lift engagement has returned. I currently have three different flavors of lift: True Lift, Bark with no Bite, and Faceplant. Faceplant is terrible, it's almost complete power loss, akin to the feeling of running into a large puddle of water at speed. Get lurched forward in the seat and the tach needle bounces wildly. All three flavors have their own sound, all will run to the fuel cut if I keep pushing (only done for diagnostic purposes). I can sometimes tell when a Faceplant is coming because the midrange feels weak.
No CELs. Air filter and MAF are new and clean, exhaust is in good shape. Oil is fresh and at the full mark. Spark plugs are new, old ones looked fine. Lift bolts were checked last time I had this issue a few months prior. Tested with two different sets of injectors and two different ECUs. Lift OCV is brand new even thou old one appears to function fine. Visually inspected and continuity checked all lift related wires. No new work that could've cause this. Now that I finally replaced my wideband sensor I have learned when in True Lift or Bark with no Bite fueling looks normal in the low 11s, but in Faceplant I am in low 10s.
The last suspects: Fuel pump, VVT OCV and VVT gear. I am ruling out fuel pump due to the excessive rich condition when I hit Faceplant. I have another new OCV but installation takes a bit more effort with the engine mid-mounted so haven't done that yet. Given how clean the VVTL OCV was I don't expect any different of the VVT OCV, but I'm going to replace it anyway. I am also going to replace the VVT gear, which has done the cold start clatter since I installed the engine 3 years ago. It's recently (in the last week) gone from a second or two of clatter at 1500rpm to a second or two of clatter at 500ish rpm during which the engine sounds like it may just sputter out. After some digging around on newcelica this afternoon I found a handful of cases where owners had VTC gears blowing apart, most claiming it happened under normal driving conditions and not when hammering on the car. Precursors to this were cold start clatter, intermittent low performance and intermittent lift issues. Exploding VTC gears are pretty rare, but I know mine has gone from bad shape to worse shape recently and I don't want to deal with any holes in my engine so... I am going to drive home gently tonight and park my toy until the new VTC gear and OCV are installed.
If anyone has any other ideas about what this could be I am all ears. Otherwise... I'll update when I get around to it. There are a few other projects in front of this one unfortunately.
It would appear that you have thought this out well so I do not have much to add except to say while you are replacing the cam phaser
1. Check the condition of the intake cam for any wiping
2.Check the clearances to make sure they are in specification
3. Examine the lift pads for any excessive wear
4. Closely examine the rockers for any cracks.
5. And last check the lift bolts once more.
I also heard of phaser issues and It is believed that chatter is due to the lock pin which they redesigned in later years. I don't remember but I think my 2003 matrix engine got a revised phaser. I have no noise but I have heard it on other peoples cars that are earlier 1ZZs. I have also heard of those that had the lock pin jammed because they did not follow the procedure of unlocking the VVT phaser before installing it on the cam which reduced power.
@dblotii I haven't actually logged conditions for each version of lift I've gotten but I can't determine any logic to it. I had the same thought regarding oil pressure because at one point it seemed like Faceplant was more likely to happen if I stayed in the midrange for a long period of time before hitting the threshold. Then Faceplant started happening on the first pull of the day, second gear highway on-ramp just one mile from my house, with coolant temps at about 150F. A couple days ago this happened, didn't attempt lift again the entire drive. On the return drive I tried it again and got the True hard hitting lift through 2+3+4 (excessive yes, but didn't want it to end). Probably hit lift 10x on the drive home and it worked flawlessly every time. Next morning Faceplant again.
I also had a period where I thought lift was more prone to fail if my oil was any amount below the full mark, and that it worked better running 10w40 rather than 5w30. But the problem came back regardless. What version of lift I get truly appears to be random.
@dev I absolutely plan to check everything while I've got it all open. Last time I had the cover off about 6 months or so ago the head looked great. Very minimal wear marks on cams and lift bolts, and the amsoil appears to slowly be cleaning up the minor yellowing that was present when I got the engine. Haven't ever checked clearances on anything besides Honda engines so will have to read up on that.
@dblotii I haven't actually logged conditions for each version of lift I've gotten but I can't determine any logic to it. I had the same thought regarding oil pressure because at one point it seemed like Faceplant was more likely to happen if I stayed in the midrange for a long period of time before hitting the threshold. Then Faceplant started happening on the first pull of the day, second gear highway on-ramp just one mile from my house, with coolant temps at about 150F. A couple days ago this happened, didn't attempt lift again the entire drive. On the return drive I tried it again and got the True hard hitting lift through 2+3+4 (excessive yes, but didn't want it to end). Probably hit lift 10x on the drive home and it worked flawlessly every time. Next morning Faceplant again.
I also had a period where I thought lift was more prone to fail if my oil was any amount below the full mark, and that it worked better running 10w40 rather than 5w30. But the problem came back regardless. What version of lift I get truly appears to be random.
@dev I absolutely plan to check everything while I've got it all open. Last time I had the cover off about 6 months or so ago the head looked great. Very minimal wear marks on cams and lift bolts, and the amsoil appears to slowly be cleaning up the yellowing that was present when I got the engine. Haven't ever checked clearances on anything besides Honda engines so will have to read up on that.
Very easy to check the clearances. Just make sure to check the revised way of doing it that was published in later service manuals for the values that is measured at the cam rollers and not from the earlier books that specify to measure at the lifters. Its not just the location of measure but also the values may have been revised based on better tolerances as time progressed for Toyota to know what is best for the longevity of the cams and rockers.
The current formulations for Amsoil is good stuff. In time it should clean out all that yellowing.
When I first installed my engine around 2007 there was a hint of yellow on the head.
When I removed the cover sometime around 2016 it was spotless thanks to the Euro Castrol. I even opened up the cam phaser cover plate and it looked brand new. Its no wonder my engine has none of those ticking sounds you hear from these ZZ engines as they age.
Now I am using the Pennzoil SRT oil which is even better for cleaning up deposit formation or not leaving any behind. I have seen too many cars that run Mobil one that have turned the insides yellow. The SRT oil also has very low evaporation losses that would have me consume some oil if I go into lift a lot but now the dipstick is always full.
@dev that looks super clean! Looking at my old pics and even yours now I see we both have older editions of the cam gear. The newest (fourth), and maybe even previous (third) gen have special bolts on the cover to keep us out.
@dev that looks super clean! Looking at my old pics and even yours now I see we both have older editions of the cam gear. The newest (fourth), and maybe even previous (third) gen have special bolts on the cover to keep us out.
I don't remember exactly but I read somewhere there were a few revisions of the phaser. The reason why I had to remove the plate was to unlock the pin as a last resort. I was initially able to unlock the pin using compressed air and black tape to block off the holes but stupidly I locked it again out of curiosity and then for some reason compressed air trick did not work maybe because it needs residual oil in the passages to push the pin to overcome the spring resistance.
The bolt pattern on the plate was not conventional, it required a special socket to remove. I used a bolt out to get them off.
Actually I have been kind of worried because I tightened down the bolts on reassembly and did not have any torque specs or even know if it mattered. I guess not as everything turned out fine. What I don't understand is why Toyota doesn't want anyone to mess with opening up the phaser. This is the only device on this car I have found where they use special bolts. Maybe they were concerned with someone clocking it the wrong way. Another good thing about using quality oil is keeping those seals in the phaser well lubricated so they don't shrink or swell with age.
@dev I know the torque spec for the center bolt is 40ftlbs with the gear unlocked, then lock it again after. Haven't come across specs for the phaser cover itself. Have also read unlocking a new one can be (more) tricky without oil in it. Some even suggest shooting wd-40 or similar in it beforehand helps.
Some of the folk who had exploding cam gears did report it appeared the plate cover bolts backed their way out and we're scratching against the inside of the valve cover shortly before catastrophe. Some found whole bolts, unbroken inside their engines.
@dev I know the torque spec for the center bolt is 40ftlbs with the gear unlocked, then lock it again after. Haven't come across specs for the phaser cover itself. Have also read unlocking a new one can be (more) tricky without oil in it. Some even suggest shooting wd-40 or similar in it beforehand helps.
Some of the folk who had exploding cam gears did report it appeared the plate cover bolts backed their way out and we're scratching against the inside of the valve cover shortly before catastrophe. Some found whole bolts, unbroken inside their engines.
I was able to torque the center bolt to the correct spec with a friend arresting the cam. Thank god I got those plate bolts on extra tight. I was worried that it wouldn’t be tight enough but at the time I was worried it would be too tight. I guess I made the right call after what you wrote. I also taken the time to tighten the cam journal caps very carefully and evenly with a lower range torque wrench. I might be slower than others and a bit paranoid but it’s worth it. I have seen too many people not on the ball make all sorts of slip ups that cost them their engine.
A little tip, brush on some assembly lube on all the cam lobes and rockers before you start the car.
Almost back together... Was interesting getting the VVTL OCV out, but managed without having to remove any engine mounts. Clearances are impressively in spec. The new cam gear makes the rest of the head look way more yellow now. Hopefully test drive tonight.
Unlocking the new gear was a bit of a chore. After multiple failures I slapped the old one back on and tried it to make sure I wasn't doing it wrong. Old one unlocked with ease and of course spit oil everywhere. That helped me decide penetrant oil in the new cam gear wasn't enough. I let that sucker sit in a bowl of fresh oil for a few hours and viola.... Unlocked with ease.
Other lesson learned for the day... Cam lobes are sharp. May not seem so but when you grip them tightly and they're slick with oil you will get cut. My hands are fairly calloused so I didn't think about it... Until later in the day I put on some hand sanitizer... Death by a thousand cuts.
Almost back together... Was interesting getting the VVTL OCV out, but managed without having to remove any engine mounts. Clearances are impressively in spec. The new cam gear makes the rest of the head look way more yellow now. Hopefully test drive tonight.
Unlocking the new gear was a bit of a chore. After multiple failures I slapped the old one back on and tried it to make sure I wasn't doing it wrong. Old one unlocked with ease and of course spit oil everywhere. That helped me decide penetrant oil in the new cam gear wasn't enough. I let that sucker sit in a bowl of fresh oil for a few hours and viola.... Unlocked with ease.
Other lesson learned for the day... Cam lobes are sharp. May not seem so but when you grip them tightly and they're slick with oil you will get cut. My hands are fairly calloused so I didn't think about it... Until later in the day I put on some hand sanitizer... Death by a thousand cuts.
Good to hear. For fine cuts use super glue. Works better than bandages.
Well it runs and I didn't screw up the timing. Performed flawlessly for about 20 minutes then when I punched it out of a cloverleaf turn getting back on the highway it faceplanted again. Drove for about an hour last night and the bark with no bite lift appears to be nonexistent. It either works right or faceplants. Got the faceplant a second time when I tried the 6th>3rd shift at 65mph in a straight line. I'm trying not to feel too disappointed because the car does feel better as a whole and now I'm not worried about the cam gear exploding. Lift works way more often than not. Startup rattle is gone as well.
I think I solved half of a two part problem. Now I suspect the spun metal cat installed a foot downstream of the header has bit the dust already. There is a very subtle rattle sound in the exhaust I don't remember hearing before. Maybe lateral forces and/or sudden pressure changes in the exhaust are bouncing loose substrate around and causing an intermittent exhaust restriction. Might be time to head out to the country, drop the exhaust and put in my earplugs for some testing.
Only other thing I can think of is an oil pressure issue which I certainly hope it isn't. Not sure how I would track down an intermittent oil pressure loss. I also feel like I'd see more evidence of low pressure in the head if that were the case.
