Suddenly getting misfires on all four cylinders

I feel really foolish.... The PriusChat UI is so similar between the forums and conversations that I *thought* I was "posting" to the forum and, instead, I was peppering poor rjparker with a ton of questions. All I can say is this.... First, (shaking head), I'm a dufus. Second, a huge shout out to rjparker; he is truly a patient individual that has a great deal of knowledge.

OK, so now the update....

The long and the short of it is this.... I did take the car to a mechanic I trust. He looked in the cylinders, sniffed the coolant for hydrocarbons, etc. The long and the short of it is that he saw no indication that the head gasket job didn't take. He did notice a leaking oil pressure sender, so he replaced that, and felt that the timing chain sounded like it might be slapping a bit. Because a tensioner is cheap, I just replaced that. I still got the misfire codes though roughly every 300 miles or so. Not really knowing where to go next, I decided to get a fuel pump from a crunched car under the feeble hope that this might fix the problem. My rationale was simply that it was highly unlikely that both my pump and the one from a donor car would both be failing, and it was a lot cheaper than buying a brand new pump. I don't want to just "throw money" at this issue with random parts, but even people well versed in the cars seem to be scratching their heads.

So, after the fuel pump (full assembly really) swap, the codes kinda sorta went away. This car is used by my daughter that I see roughly once a month, or so, which makes it difficult to scan a lot. After about 400 miles and no codes, the next time I was able to scan the car was roughly 1300 or 1400 miles after the change. Although the MIL wasn't lit, there were pending 300, 301, 302, 303, and 304 codes. Darn. So, the fuel pump appeared to help a bit, but not fix the problem. Yes, that is a confusing statement for which I don't have a great answer.

Fast forward to yesterday, the same day that I ironically purchased a used 100K 2014 Prius V (long story). My daughter, 55 miles away) called me in a panic. The car was at a stop light, beeping, flashing lights, and not able to move.... And, of course, in a horrible part of town, and she had to be home so she could clean up for 30 people from her grad class that were showing up. So, we jumped into action, swapped a bunch of cars around and got the Prius towed back to my house. Thankfully, rjparker had suggested that I upgrade to AAA Premium so I got long distance towing... I took that advice and it paid off.

I am now getting P0011 and P0335 codes. The car *does* run (my daughter wasn't quite right in that, but I understand) but doesn't sound good. There is a ticking sound that is very odd, almost like a slap, even though it is fairly smooth (not like when the HG went and the engine was bouncing). The two codes being thrown now are for crankshaft position and camshaft position, so the ticking kind of makes sense. I have not had a chance to look at either of these any further.

My first order of business was probably to probably just replace the crankshaft position sensor. IIRC, it is pretty low on the engine, and that is where a lot of oil was being thrown about from the leaking transducer that the mechanic replaced. Or... maybe I should check the wiring? How often does a crankshaft sensor go out versus a wiring issue?

Of course the next big set of questions is.... Are all of these faults related? At the very least, is the camshaft position fault (0011) likely to be related to the crankshaft fault? It seems highly unlikely that I'm having two faults at the same exact time that are completely unrelated. Or could the more likely scenario be that the ECM has an issue? And, is it possible that a dying, but not dead, crankshaft sensor could be the cause behind the misfire codes too?

As for the head gasket. We've gone about 17K miles now since I did it, and about 2K since I started getting the misfire codes. The coolant level has not changed, the oil is not cloudy, the engine was smooth and there has been nothing to suggest the gasket is failing. Am I willing to accept that it still could be an issue? Absolutely. I am willing and happy to entertain suggestions that it could still be a problem.

Assuming that the HG is good, and the 0011 and 0335 codes are completely unrelated to the misfires, it means that the misfire problem still exists. I think I've ruled out the fuel pump/filter now, but not the injectors. The MIL has shown up when driving at freeway speeds after about 1/2 or so, which might indicate some association with heat. There is some suggestion that given the timing of when the MIL finally lights, that the EGR system is likely not the fault, but all of this is "well, maybe, kind of, probably" stuff; there are no absolutes. The current running thought is that the misfires, if independent from the crank/cam sensor stuff, might be related to a bad coil pack that fails due to heat.

This is kind of a long summary of what has been happening and what poor rjparker has been graciously helping me with. Again, I apologize to him and to the group here. I generally hope that these posts can help others with similar problems so I don't try to keep them in private messages.

Any thoughts about the misfire codes, the crank/cam sensor codes/issues, whether these are linked together, and the coil pack theory are all things I'd love to hear opinions on.

Happy Holidays!

 

hotel: I mentioned the tensioner but even the mechanic thought it was a long shot. I looked at the one I removed very carefully, and it was in perfect operating condition, as best as I could tell. And the motor has run fine (except for the misfire codes) for the last almost 2000 miles. It was only two days ago that things went really south. Whether the misfires and crank/cam sensors are related is definitely something I kind of suspect but don't want to assume. Right now, however, I'm fairly confident that the timing chain is correct.

Tim: I'm not ready to sell this one yet. Other than the kinks that have plagued me recently, the car has been very reliable, economical, and comfortable. It is also in very good condition.

I have a theory.... I am thinking that the leaking pressure transducer's putting a bunch of oil on the back side of the engine might be the problem. If I'm not mistaken, that transducer is right above the crank sensor. If a bunch of oil got into the connector for the CKP (maybe the seal isn't good?) then that could foul up a lot of stuff. It could cause the original misfires and, after a complete failure, result in the current crisis.

Because everyone seems to suspect the CKP first, that is where I'll be concentrating my efforts today, assuming it warms up a bit. Right now it is 35 out there.

 

Medel,
You know.... I have wondered about that... As noted in previous posts, I *never* had any discernible coolant reduction, no overheat condition, no water in the oil, etc. One day the engine started bouncing and I *immediately* stopped driving it except for about 5 miles to/from the dealer, etc. The car didn't even have a MIL until roughly the last start. After removal, I checked the head with a precision rule and feeler gauges and I couldn't find any issues. BUT, I'm not a pro. So I took the head to a reputable shop for magnaflux, valve stem seal installation, and checking. I was a little surprised when they said they did deck the head because it was out.

Anyhow, I had no issues (well, no MIL... there might have been codes at some point that were reset) for some 15K miles or so after the head job. I think that is probably long enough to invalidate (?) a concern that the decking might have been a problem. I don't recall how much they took off, but I don't believe it was very much. I might have it on the invoice.

So.... My QuickJack is coming in handy for making this stuff easier, although this particular job could have been done without it..... I took the connector off the crank sensor and it is as clean as a whistle. I took the sensor out and visually it all looks fine. It ohms out at about 2K and if I wave a magnet across the end, it definitely starts registering voltage. My sense is that the sensor/connector are probably fine. I need to figure out where the pin is on the ECU and measure for continuity.

I did note that my sensor is an 90919-05070 which has been replaced by a 90919-A5004. I'm not sure what the difference is.

Leadfoot. That is a good thought. I did check grounding before, but that was several thousand miles ago. Maybe I missed something, so I'll go back and confirm.

 

I checked the grounds and I couldn't see anything amiss with them. Further, I was thinking about this and I'm not sure a bad ground would actually directly affect the crank/cam sensors. Both of these have isolated grounds that are carried through the wiring harnesses. The crank is a reluctor type with two connectors. One is ground (from the ECU) and the other is the feedback from the sensor. The cam sensor, by contrast, is a hall effect type. It is provided power and ground through the harness and the third wire is the signal. The point is, the grounds are completely isolated. HOWEVER, it certainly is possible that you could have indirect consequences. One way or the other, though, my grounds were all tight and clean.

I cleared the codes after working with the crank sensor and tried the engine. It still has the same funky behavior... kind of a clanking, no power, and a code for the camshaft. Interestingly enough, I didn't get a crankshaft error. I pulled the cam sensor but I don't have a good way to test it. However, because the behavior of faulty wiring is effectively no sensor, I tried that briefly. It turns out that there is a different code that essentially says the signal is high. That makes sense because the hall effect would effectively be pulling the signal down. It is also a very cool diagnostic point because I *think* (through rationalization, but again... I'm no pro) that this is a good indication that the ECU and wiring are fine. It would point to the sensor itself as being the fault.... Again, though, I don't have a good way to test this and I don't want to buy a $120 sensor if I don't need it. So, I went to Amazon and bought a $20 aftermarket sensor. My interest isn't so much in *using* that sensor but to just see if it will suddenly make things work. If it does, I'll spring for the OEM Toyota sensor (actually made by Denso).

My sense is that I'm onto a tangible lead now, which is good. I'll know more tomorrow, but I'm definitely hoping that I'll pop the sensor in and the engine will start purring again. If it gets rid of the misfire codes too, that would be a fantastic Christmas present!... I'll keep you all posted.

Oh, for what it is worth, the cam sensor is dirt simple to replace on a Prius. You literally can access it from the top of the engine without even removing the windshield wiper cowl stuff. The hardest thing is that Toyota gives you almost no free room on the pigtail, so it is a bit difficult to pinch the retainer and remove the sensor (but NOT impossible). So, one 10mm bolt and about 5 minutes and the sensor is replaced. I hope my temporary aftermarket sensor yields good results!

 

well.... I'm crushed.... No dice. I didn't read the codes, but the new (cheap) sensor didn't get rid of the knocking sound, the engine still has no power at all, and shuts off after only a few seconds. Clearly it is still *not* happy, which puts me back at square one. My guess is that both the cam and crank sensors are fine and it is something else. From what I gather, the only other options are wiring and ECU. I *guess* it could also be something oil related. The variable camshaft actuator could fail (or the pump that feeds it, etc) and the car could interpret that as a failure of the sensor? I'm not completely sure where to go next. I have a strong suspicion that the wiring is perfectly fine, but it is definitely something I need to check. I am not sure where the pinouts on the ECU are published, so I'll have to search that out.

Q: How do you know if/when the actuator itself has failed?

I'd frustrated but still resolved to working through the problem.

 

Yeah, this thread has been swirling around a problem that has gotten progressively worse. To be honest, I'm not sure if the initial problem (misfires on all cylinders) is related to the current problem (crank and cam sensor). Given that the latter issue renders the car effectively useless, I'm treating that as my primary concern. If resolution there fixes the first issue, great, but I need to get the sensor thing fixed first.

I *think* this comment is germane because I am missing the significance of the question about fuel. To answer your question, no... I haven't checked the fuel injectors (ever), but I think that would be related to the misfire issue. I can currently start the car, but there is a knocking sound or pinging sound, when the engine starts. Pressing the accelerator does not speed up the engine, and even if I just start and leave my foot off the gas, the car will automatically shut down within a few seconds.

Without the sound, automatic shut-off, and codes, I can certainly see how I might be back looking at the fuel (pump, filter, line, injectors, etc), but it seems like these are not consistent with the knock/ping I have now. Or am I drawing incorrect conclusions there? I'm always happy to be corrected!

 

Yes, the engine is absolutely starting. But, it makes a tick tick tick sound, almost like the pinging of a valve hit on a car as you give it gas while under load. In this case, however, the car is just idling.

You know... I didn't even think about the battery issue and starts. . I haven't done that many so I'm not horribly concerned yet, but I also have no idea what is going wrong right now. So it isn't as though I'm *not* without worry that a drained battery could become a problem. However, I thought that the 12V battery was what was used for starting the car? If not, then how would you ever be able to jump it? I haven't ever needed to do this, but I recall some special blocks in the fuse area where you clip on your 12V booster (other car) for this.

If I can post a video here, then I can record the engine start and sound...

 

I am rethinking my statement about the motor actually running. Always learning, and always correcting my knowledge.... I think that 'giving it gas and getting no response' is, in retrospect, because the motor might not be running at all....

Anyhow, let me give an update. In whatever mode the car is presently in (engine starting or not), I can say that the 0335 code is not showing up after I clear the codes. The 0011 code, however, shows up immediately whether I have the original OEM sensor in there or the cheap-o thing I got from Amazon for testing.

I'll see if I can upload the video, but there was an odd event when I was making the video that hasn't happened before. About halfway through, you'll hear a "pop" almost like a small backfire. That was really odd.

So.... I have a tangential question... If the HV battery is needed for starting, how do I handle a situation where the HV battery is drained? Now I'm really worried about *that*.

Here is the video:
https://youtube.com/shorts/zlXBB8nfdZQ?feature=share

 

Yep, that makes sense. The whole dance of the Prius is really quite fascinating from an engineering perspective. That said, right now I'm actually in a bit of panic. I can't seem to get a grasp on the actual problem, and now I feel like Marie Antoinette with a guillotine hanging over my neck. Diagnosing an unknown will inevitably require actually trying to start the car... But if the HV battery gets low, then I've got a whole new set of problems.... Worse, I'm not even really sure how low it is right now.

I suppose that in a worst case scenario, I could take out each of the battery cells and charge them, but that would redefine PITA and is definitely not something I want to do. Alternatively (and pack safer), I could move the pack from (bad) Prius V #1 to (good) Prius V #2 and drive it around a while to charge it.... Equally a PITA though.

Did you have an opportunity to look at that video? If this is some broken connecting rod or other mechanical issue (translation: need a new engine) then I'll abort my diagnosis steps right now).