Suddenly getting misfires on all four cylinders

No, I put those on, not the machine shop. A mechanic popped the cover off about 2000 miles ago for a look see when I was having the misfire issues, but he didn't do anything with the cams/valves. It appears as though the underlying mystery is still there.

I should also say that I can actually remove ones that *are* in the correct orientation and were so when I removed the valve cover.

 

I haven't seen that comment, but I have thought about the timing chain before. It is not possible for me to check its length very well without removing it from the car so I haven't make that check. That said, I don't think it is the issue. The car had 103K when I did the head job, which isn't really all that much. I don't think a chain will *stretch* so much as wear. But I changed the oil pretty methodically, and 103K (mileage at HG change) isn't really that much. Therefore, my (albeit inexperienced) view was that the timing chain was fine then and is likely still fine.

The real kicker here, and what caused me to make the final move towards purchasing a replacement engine, was the rocker issue. There is no scenario I'm aware of where the rockers should be completely without at leas *some* pressure against the cam. The way it is right now, I think I can literally flick all of the rockers on the intake side into the valve vault (i.e. remove them from the engine). The exhaust cam still keeps those rockers firmly in place. I can think of only five ways that the intake side can have this type of odd behavior.

1. The cam is riding high. That would mean that every bearing/retainer would have to be broken or bent; however, there is no damage at all there. The cam looks to be sitting perfectly in the bearings.
2. The tappets were installed reverse. Greg sent posted some photos a few back of what this would look like; my rockers are, and have always been, properly oriented.
3. The caps on top of the valves are missing.... However, I am absolutely sure that they were all installed (triple checked that). Further, on all of the cases where the rockers were dislodged, the caps were still in place
4. The tappets are worn/low/etc. This is actually the one I wonder about the most. The tappets are hydraulic with an orifice at the top. I can imagine how they'd push UP once oil is coursing through the system. But... the exhaust side is the same as the intake side. They use the same tappets and the exhaust side is fine. Still, this area is one of my suspicions
5. The valves got bent and are no long able to travel to their upper limit. This limited travel would prevent the valve stem from pushing up against the tappet which, in turn, would push the tappet against the cam. This is also up there as a probable cause

The kicker here, however, is that the last two are both deeper in the engine... If the oil pump were somehow broken, that could obviously introduce even more problems. But, at the very least, I'll need to take the head off again, which removes removing the front cover, etc, etc. I'm digging pretty deep and it will be the second time around. I want this to be *reliable* transportation for my daughter... It doesn't make any sane father happy when his daughter hears about a bunch of people cat calling her in the middle of a bad part of town while waiting for a tow truck. I want to minimize the probability that this could occur again.

So, that was the logic behind my buying a new engine. Hybrid Pitstop seems to have a good reputation and Greg's customer service has been stellar. I only have a few dings about my experience. The first was the shipping price quoted, which was about $700/$900 (terminal/home) for about 380 miles. I don't think HP is pocketing any of that though, but it was so high that I went shopping for my own. They were fine with that and I managed to get FedEx 1 day service for $220 to the terminal (another $100 if I wanted delivery to my home, even though I actually have a small forklift (metalworking hobby) and I'm only 5 miles from the terminal). The second ding was that I am stunned that HP doesn't have a small forklift for loading engines on a truck. The net result is that I got hit with another $100 charge from the shipping company for a liftgate. So now the shipping was $320. A small forklift, even a manual foot-jack type, which would work fine for a 200 lbs engine, is pretty cheap used. The final ding was a 120 or 150, don't recall which, service change that cropped up on the invoice. I'm not sure what that was for, but I'm guessing it was prep for shipping. Unfortunately it was never really discussed so it surprised me. But, I also understand where it might have come from so I really didn't even ask. The point is this, though.... By the time I add even my shipping charges up, I probably would have just chosen to make a long day of it and drive down to pickup the engine. In the end, I probably would have picked up other bits and pieces at the same time and also gotten to meet Greg. I can't say enough positives about his customer support skills. The "dings", in my opinion, are not really very significant. If this engine works as I expect, I'll be pleased and will happily recommend HP and Greg.

Back to the existing engine.... Sadly, the weather is changing here this week, so I will probably not be able to install the engine until Sunday (or later... I have to work again next week). Eventually, however, when I get my original engine out of the car, I absolutely plan to take it apart and determine the reason the rockers are loose. I'll also measure the chain, etc, etc. I do have fairly high confidence that I'll find the underlying cause. This will also allow me to scavenge spare parts that I might want to keep.

For those that might be curious, although I may have mentioned this before.... I elected to purchase the gold version of the engine. I mainly did this to obtain the different pistons/rings that came with the later engines, in a hope that I might reduce/eliminate the dreaded oil consumption issue. This upgrade also gives me the spin on oil filter which will be a nice change. I'll be adding the PVC oil separator can at the same time; I don't know how much benefit I'll derive from this, but the thing is only about $20 on Amazon so why not...

 

Unfortunately, I don't have a vehicle capable of trailering that load.

 

Exactly, that is what I was attempting to say on both counts... Wear would be exacerbated by a dirty environment too, and I was generally pretty careful about oil changes.... As for the rocker, yes... Rationally, throughout the full cycle of the cam, the rockers should never be free to just pop off the valve. Even if chain wear were to be an issue, I would think that it would largely result in poorer fuel economy. But even there, the ECU should be able to adjust for wear. Well, to a degree. The exhaust and intake cams are tightly bound. There is only one adjustment point and that is on the intake cam gear.

 

FedEx terminal pick-up was a cinch. The only screwup on my part is that I should have dumped my trailer and just stuck with the van. FedEx has such low mast height forklifts, that I could easily have just used that and it would have save me a lot of hassle setting up the trailer (it is one of those fold up things because I don't need it very often). I haven't unwrapped the engine yet, though. The weather here is unsettled for several days, so I actually moved the engine into my van to avoid moisture. All in, though, it looked to be well packaged. The banding lost a lot of its "tightness" but that isn't the end of the world.

Two days ago I picked up an engine hoist on CraigsList too. So, I'm in good shape there. I actually have a forklift for my metalworking hobby, but the lift is generally stowed away and is a bit difficult to get out. Therefore, a hoist seemed like a good thing to get.

I plan on working to remove the old engine on Sunday, weather permitting. We'll see if I can get to the installation.

oh, I also picked up a stainless steel catalytic converter shield from MillerCat. They are local and about 3 blocks from the FedEx freight terminal. (the shield is for the Prius V I just purchased... I already have a shield on the V I'm putting the engine into)

 

OK, that just pisses me off. I had to pay $100 more for a liftgate pickup, and then they don't even send the right truck? That is wrong on so many levels. I apologize for that, although it was entirely out of my control. Even the BOL shows that it should have been picked up with the gate.

 

Yeah, sadly I agree with you. For this particular case, I probably would have told them to come back with the appropriate equipment. But, I wasn't there. Shipping was actually faster than I expected (overnight) because LA isn't that far away. So long as I had the engine at FedEX by Friday, I would have been happy. That said, weather did turn into a bit of an issue in this whole thing. CA has been in the middle of a drought (and still is), but this week there has been a decent amount of rain forecasted (although they are always wrong). Thur was supposed to have quite a bit but it was actually pretty dry. Today (Fri) and tomorrow are supposed to have the worst. My original intent was to pickup the engine Wed, but that wasn't possible due to a perfect storm of personal stuff. If the weather today is as originally predicted, I wouldn't want to get the engine today, and FedEX isn't open during the weekend.

 

The weather here has *not* cooperated one iota, so I've had to become creative.... I have all my tools lined up in the back of the van and the hatch open... very convenient. On the Prius, I put a tarp across the top of the car and "pinned" it in the front doors, it then extends over the top of the opened hook, thereby keeping any water off the windshield where it will go down into the engine cavity. It hasn't rained hard, but there have been some bursts.

I have the old engine out and the new one in. The whole endeavor was pretty easy, actually. I have a few (but not many) photos because I was doing everything myself. The most difficult thing, frankly, was probably torquing down the dampener. Good God, getting the 1/4 turn on the 8 bolts is pretty darned tough! Between that and the LocTite, I am not sure it will ever come off again. But, I also don't think there will ever be a need. The car has 120K on it right now.

The only thing I'm missing is the torque for the (think it is 8, off the top of my head) bolts that hold the engine to the transmission. I can't seem to find that. Does anybody know?

I found the answer.... 24 ft/lbs

 

OK, I was finally able to get *all* of the fluids so that I could finish up the job. And... I did the "first start". Kind of cool, really. It was a bit loud, and definitely a bit rough, but I am guessing that is normal. The oil has to get fed into the system the cam has to adjust, the chain has to tighten, the fuel has to get back into the tube from the injectors, etc. That "roughness" persisted as some hiccups, but again, I'm *guessing* that is all kind of normal, as is the burnoff of residual oil around the engine bay for the first few minutes. I've seen others mention that, so I think it is normal (albeit a bit nerve wracking) too.

I put the car into maintenance mode and let it idle for probably 25 minutes. I monitored the temp too, but it was cool out and the cooling fans never did come on. That struck me as a little odd but not horribly so.

All that was good, so I went for a little drive. Crap. That didn't go as well as I would have liked. When I *slowly* accelerate, the car shudders and kind of "bucks". It is definitely new. And if I get up to about 20 or 25mph and try to drive at that speed, it has a pretty good shudder/buck. I'd like input on this. I'm pretty sure I didn't miss any hoses, such as the PCV valve, and such but???? The only other thing I'm wondering about is the EGR valve. I took it apart to clean it. When I didn't this before, that included taking the motor off so that I could clean the seat. Is this a problem with the EGR?

I feel kind of like a happy kid but sitting on a precipice, waiting for that joy to come crashing down...

 

Codes are yet to be checked due to time. Regarding maintenance mode.... That makes sense. The HV battery does show up as half to three quarter full on the display, although the algorithm for that is questionable. I did drive it enough that it should have charged sufficiently to no longer be bucking due to a low battery. My comments were not related to the first 300 feet, they were consistent after 1.5 to 2 miles. However, it was late yesterday when I got a chance to try this. Further, I wanted to check the hoses, intake manifold and EGR valve again before additional driving.

Regarding experience. You get experience by working on something. None of this is rocket science, but there definitely is domain expertise, which is where PriusChat comes into play. I am very mechanically, electrically, and software inclined, and have worked professionally in those industries for decades. I also fully know my limits as well as good processes in that I follow the service manual, torque everything, double/triple check, etc. That said, I definitely can make mistake, just as anyone has, even experienced professions. I've actually had some very good conversations about the Prius with the individual that has historically maintained the car. He was quite confident that this job was well within my realm of abilities. So, honestly, I don't feel out of my depth on this job, but that is also why I am posting when I have questions/concerns. I want this to be done correctly so a pulse check is always good. Plus, it helps others wanting to do the same job also learn.

 

OK.... I decided to give this another stab.... I have an OBDLink MX+ scanner and I didn't have any codes in the entire system.

I checked all of the bolts on the intake manifold, and EGR system, just to be sure they were all torqued properly. I also confirmed that the PCV hose was connected (both ends) as well as all other hoses. Nothing was wrong there. I took off the stator (black cover) on the EGR valve. That was actually interesting. I removed the armature (magnet) and depressed the EGR valve a few times. It was actually a little stickier than I would have liked, but not horribly so. I worked it several times and it became less sticky. It almost had that "too clean" feeling of metal on metal, if that makes any sense.

I then took the car for a test drive. Interestingly, my initial feeling (not enough time to say this is an accurate statement yet) is that is is smooth when cool. This led me to think that maybe the EGR was the issue and things were good again. I did a little city driving and then did a 2.5 mile hop on the freeway to the next exit. When I got off the freeway, I started to feel the shudder again, so I tried to profile that on city streets.

Where it is very prevalent is low speeds (25 to 33MPH or so) with very little, or no, acceleration. I'm guessing this would classify as a true hybrid/gas mode of propulsion. The engine, which I've intentionally had running, sounds like it is purring along smoothly, so the shuddering doesn't *appear* to be coming for there. Add a little gas and the shuddering goes away, let off and the shudder slowly comes back.

If I run in pure electric mode (obviously fairly low speeds), I don't seem to have any shudder.

One thing of interest here is that the HV battery was low when the car was dropped off in my driveway. Is it possible that there is an issue with it? I'd think that I'd be getting an HV DTC if there were a problem there, which I'm not, but it does have me wondering a bit. I also changed the transmission oil and replaced it with Toyota WS, but that is the stock oil so I can't see it is an issue (but want to disclose the work done). At this point, though, I think the concerns about low voltage on the HV battery due to maintenance mode should be nullified. Having 10 miles on the car in mixed mode, I've seen the HV battery monitor move up and down as one typically experiences with a Prius.

I do have the Dr. Prius app so I could check the quality of the HV battery. However, that requires flooring the accelerator with the brake on (very odd feeling) for quite some time. That feels weird to me to start with, but with an engine that is recently rebuilt, I definitely don't want to be flooring the engine (well, I'll let Greg comment on that, seeing as the engine came through him).

FWIW, I am also not against taking this to a mechanic that works on cars for a living. I did this when the consensus was that the HG job did not work. I'd rather not take this step, but if there is a legitimate concern about whether or not I did a step incorrectly (such as the HG), I'm happy to have confirmation (in that particular case, the mechanic felt very confident that the HG was fine, but that was on my old engine, so it is academic now).

On a completely tangential note..... The Gods apparently don't love me. We had heavy rain/winds a few days ago. Yep.... Because the subject Prius was in the driveway so I could work on it, the "new" Prius was in the street. If it had been 1.5 feet further forward, I'd have been safe, but a tree limb snapped (about 350 pounds) and clipped the left rear. There is a massive dent just behind the left rear window, a smashed tail light, smaller dents in the roof, and scratches. Oh well. The *good* news is that because the car isn't that old, I decided to keep comprehensive on it, and a $250 deductible was not a big difference. So I am covered but... argh! Oh, and all the repair places are all booked up from the other tree limbs that kissed cars.

 

I would rather wait until it is broken in. That just seems like the judicious thing to do, although I am happy that you don't feel it would be a horrible thing. If it comes down to discounting the HV battery, I may go ahead with the test, but only as a last recourse.

• Spark plugs are 17K old and Toyota OEM.
• Coil packs are a concern for me, and have been for a while now. They are 120K old. I'm not registering any misfire codes, and the engine also doesn't sound like it has any hiccups while the shuddering is going on.
• Fuel injectors are from you guys when I got the engine. I think they are probably used, but when you flow tested them, that obviously verified that they were working... and again, no perceived hiccups from the engine (audible.. for whatever that is worth). O-rings on top of the injectors are from you guys (HP) and are were supposed to be new. Grommet on the bottom end (head) is original but still pliable and such.
• MAF is original, but no codes and same comment about engine hiccups.

Please note that I fully recognize that ears are only so good. It *could* be the engine and it is just outside my ability to discern the variations.