Knocking at startup, turns off after 10 sec, please help!

Hello everybody, I am in great need as I’m confused and unsure of what to do at this point.

I’ve got a 2010 Prius III with 243k miles. It’s had a knock before and after cleaning the manifold/egr all seemed well for about 75k miles. The knocking is somewhat new and I suspected (still do) that it could be the head gasket. Well I went ahead and looked over the intake manifold and egr and they were all gunked up, so I thoroughly cleaned them, I mean really went to town until getting completely diminishing returns and brake cleaner no longer did anything. Lots of pressure washing and grease removal spray/ cans of brake cleaner. Anyway, I put all that back on, tried firing it up and the car shook much worse, had three codes and turned off after ten seconds.

Engine codes were (via Dr Prius app) P0102, P0113, and P3190. Well it turns out my MAF sensor wasn’t plugged in. I cleaned both my MAF and MAP sensors with MAF cleaner and also really cleaned up the throttle body well with a rag and parts cleaner/ a pick and rag over it to get it all. Anyway, with all that done it’s still acting up, will start, shake like crazy for 10 seconds or so then shut off. Electrical still on but engine off, same codes still.

I’m very open to try whatever, I’m not a mechanic but up to learn and try, also already ordered the head gasket kit from Toyota and will give that a shot if I can figure out how to attach the coolant pressure tester from o reilly to the coolant fill opening and use a cheap boroscope I bought recently.

I’ll try and load a video of trying to run the engine recently. I know it’s dangerous to keep on trying this so I’m trying to minimize what I’m doing, also I plan to clean this engine bay up over the next few days. I love this car and know the easy answer is send it out to the farm but if there’s a way I can fix it I would absolutely favor that option. Thanks for any help!

- Lance

 

All injector wires seemed secure, I’ll be off work tomorrow and can double check.

The miles are almost all mine, I bought it in 2012 with 29k, now I’m at 243k, no gasket sealer ever used. The egr and intake manifold are in extremely good shape now, it does seem like I need to see if it’s the head gasket. I loaded a video on to the media pages, or maybe it can be viewed from looking at my profile? I’m still very new to figuring out how this site works but it shows the engine starting and running for about 12 seconds. I’ll try using the pressure gauge tomorrow while looking in the cylinders as well as just cleaning up the engine and double checking that I don’t have any cracked hose lines.

 

Update: here’s a link to YouTube of the knocking noise after cleaning the egr and intake manifold very well and putting it all back in. Since then I’ve taken a lot apart, reached the head gasket to find… no much really. It looked surprisingly good and that was actually a little disheartening since I’m not sure what to do now. I don’t want to put it all back together (with a new gasket of course) and the knock still happen. I’ll post many pictures and clean the EGR again (it seemed to dirty up some more after only these attempts at stating the engine again) and replace the PCV as well as new spark plugs, my current ones looked pretty bad. Any thoughts at all on what I could do to help diagnose the problem with my engine fairly exposed would be extremely helpful.

 

https://youtube.com/shorts/F-nTKl2cA6k?si=NEuKYufDgxDmN4Jl

- before tearing down the engine to the head gasket.

 

Pictures thus far. Head gasket doesn’t appear to have any obvious leaking points, I see no scaring in the cylinders either.

 

Another little bit of info here: I probably have about 2 gallons of fuel in the tank. Before I parked the car in the garage it would shake for a few seconds and then stop, but after I lifted the front end of the car up and cleaned the egr/intake manifold it just shook the whole time and the engine would stop. In wondering if there wasn’t enough fuel getting where it needed to go since the car was/is on an incline. I’ve heard of some people replacing the fuel filter/pump setup as a possible culprit also but I know that’s a contentious issue since Toyota doesn’t actually recommend changing it. Just throwing out anything I can think of here.

 

@rjparker - I sure wish I would have just accepted that obvious truth before my deep dive but I was too far gone before realizing it all. I had a mobile mechanic come by when the car was torn apart before installing the new head gasket just to check and help me make a plan. Then I had the head resurfaced and cleaned out, new plugs, etc. ($300). After putting her all back together she still had a rough time knocking and the mechanic came out again and it actually sounded much better that time and he concluded it was probably a lifter that was getting lubricared over time and getting better.

Something was still wrong though, she just felt like she was sluggish. I had new spark plugs, new ignition coils, new o rings on the fuel injectors, clean manifold and egr, the head gasket was great the battery with less than 1,000 miles on her (replacement lithium pack I got a while back) and importantly no more engine or battery codes at all.

I drove around for a few days, back and forth from work, probably put 300 miles on her in a week then the last test was to do a run to some family land 150 miles away. I was averaging about 38 mpg at 70 mph and knew it was off. Well on the way home I heard a big BANG!!! White smoke behind the car, red triangle light, check engine light. I pulled over, looked under and it was leaking oil like crazy. I limped about a half mile into a small town parts store where they showed me the hole in my block where a rod had shot through. 243k miles in, and she’s done. I’m super bummed and unsure of what to do with the car now. I bought the battery pack a year and a half ago, the first one had an issue and was replaced, I had just put the new one on after the head gasket replacement so it’s like like I just shelled that cash out for the battery but still within the past two years.

Now what to do with the car/very new great battery. I’m reluctant to spend 5k on a new engine job since besides the battery the rest of the car also has a quarter million miles… and besides my wife is highly against it.

So the original knocking noise… spark plugs? Ignition coils? Who knows. But it was all for not. At least I learned a lot in the process. Thank you all for your input on this, it was helpful and kept me going.