Did my timing chain slip and cause multiple misfires?

I've had my 2014 Tundra since 2017 and she now has 218k on her. For the last 50k or so I've had the all to common timing chain tensioner rattle from time to time. Especially as I get near to the oil change interval.
A couple of weeks back It was in the 20F's outside and I started the truck to warm it up before leaving. No unusual noises or anything but when I went to leave the neighborhood I got the flashing CEL indicating a misfire. No knocks or clunks etc just the misfiring. I returned home and put the scan tool on it and it showed a P0301 code for a Cylinder 1 misfire. I was using a NON OEM coil on that cylinder so my first thought was that was the issue. Before going to the parts to store to warranty that Coil I moved it to cylinder 3. After clearing the codes this time I still had the misfire but now the misfire was on both cylinder 1 and 3 (P0303). I then checked the plug on Cylinder 1 and though it was a little sooty it definitely was in good working order (NGK laser iridium plugs - which I took pictures of to confirm with NGK they were authentic) and the plug on cylinder 3 was good too.

My next thought was an injector on Cylinder 1 so I removed and cleaned and ran carb cleaner through all 4 bank 1 injectors and all appeared normal.

Cleared and Checked the codes again and I had pending codes of P0301, P0303 and I had added 2 new ones P0300 multi cylinder misfire and a P219A (P219A Bank 1 Air/Fuel Ratio Imbalance).

I checked and cleaned the original PCV valve and it was a little oily but functional (rattles easily). The Mass Air sensor is less than a year old also so it shouldn't be that.

I am running all original O2 sensors but I've never thrown a code on them.

It was at this point that I noticed the timing chain tensioner rattle was NOT happening anymore. It had always been intermittent but it's not happening at all now. It dawned on me that a timing chain related failure could cause issues like I'm having. Before I have the truck towed is there anything else I could try?

Thank you in advance!

 

You can remove the oil fill tube from the valve cover and put eyes on the tensioner that usually fails. Not sure how helpful that will be.

 

The only way to know for sure is to do a compression check, and if if is abnormal a leak down test. I have found by the time you are done messing around with the “could be’s” you could have knocked it out and at least know what you are dealing with. You can also drop a scope down the cylinder and check the top of the piston for witness marks.

 

Is it a dead miss? Like a hard miss? Wonder if it broke a valve spring.. I believe that could cause the imbalance code. The 2grfks engines in the tacomas have issues with valve seat issues so maybe it could be that too. I don’t think it’s timing related as you don’t have any correlation codes. Also a pinched injector o-ring could cause a vacuum leak too. So maybe check them as well.

 

if your chain skipped your engine would not only struggle to start (or not start), you'd have bent valves and essentially seize the engine. The chains may have some slack in them but the tensioners and guides keep enough tension to keep them from jumping a tooth or more. You'd have to get to "ecoboost" levels of timing chain stretch to make this even a remote possibility. Not to mention the noises your engine would make.

Lastly if the chains slip you'd have about 5-6 other codes related to cam position, crank position, and "correlation" codes for the same, and misfire codes on multiple random cylinders.

I would change the plugs and coils on cylinder 1 and 3. If you are still getting O2 codes then try swapping a new, vin-matched, mass air sensor in place.

If misfire codes still prevail, start looking for mice or rodent damage on wiring. Check connections also.

Also what weight of oil are you using? I've seen some strange behavior from overhead cam engines of multiple different oems when using viscosity grades above 5w 30.

 

Double post...

 

If you don’t have cam/crank correlation code then your timing chain did not skip a tooth. If you were out one tooth the truck won’t through misfire codes, just the correlation code.

 

I would go to your local auto parts store or stealership and replace all your plugs. I started having some random misfires, but no codes. My misfire started with cyl 5, then cyl 1 then cyl 8, but cyl 5 was the main issue and it sounding like I had to replace the timing chain retainer. Once I got a code for it, I got new NGK plugs and began replacing all of them, but I got cheapo plugs and didn't last as long as they should. The noise and misfires went away, if you got your plugs from ebay or Amazon, I would consider replacing all of them.

 

I have a cheap endoscope coming today to get a look inside at both of those locations so I’ll post pictures tonight.

When I drove the short distance I did it was sluggish and the idle is rough enough I’d say it’s a dead miss. No knocking or mechanical noises or anything though.

I’m going to get all 8 injectors rebuilt locally so we’ll see on that. That was my first thought after coil originally.

I saw another post where a similar issue ended up being a broken exhaust valve spring.

Ok that’s good to hear on timing, no timing codes so it’s not that.
The MAF sensor I replaced last year was Toyota but not VIN matched (I didn’t know that was a thing or needed).
I’ve already replaced coil one with an OEM Denso coil but I’ll get another for coil 3 too. Plugs all have approximately 25k on them but they’re cheap enough I’ll put a new set in.

I wondered about mice or rodent damage too, it’s was so cold when this all started and we have approximately 1000 squirrels ️ here in our trees. I’ll look for that too. I hadn’t noticed anything but I’ll dig deeper.
I’m running 5w30 always full synthetic.

One other question, My Optima yellow top is 4 years old. Could a battery do this? I’m having no other electrical related symptoms so I assumed not but the week this started it was single digits overnight.

Ok thank you!

These are NGK Laser Iridium plugs from Amazon and read online about fake plugs, called NGK and they sent me an email to reply with specific pictures and they confirmed them to be authentic. These plugs have less than 25k on them but I’ll be replacing them all with factory Denso plugs I think.

 

I’ve had plugs ‘carbon track’ after a cold spell. That was in a mustang gt but it was similar situation. Perfectly good running engine. Started it up in very cold weather and two of 8 plugs ceramic shit the bed.

 

What do you all make of this? Anything alarming for 210,000+?

This is Cylinder #1 & the piston appears to be all the way to the top
2 Valves look a touch open and 2 closed

 

Rotate the crankshaft 1 full turn and take another look. If the valves are all closed at that point, it’s normal. I think your pics are showing near TDC on valve overlap between the exhaust and intake strokes so if you turn the crank a full rotation you should be near TDC on the compression or power stroke, depending on which side of TDC it actually is.

Edit:
On my second look, things look way too clean inside that cylinder, I’m not talking about the cylinder walls but the head dome and even what appears to be an intake valve. Are you loosing any coolant? I’m concerned that you have coolant leaking into the cylinder, which would most likely be a head gasket leak. The carbon on the top of the cylinder wall in your 2nd pic even looks wet to me.

 

Nice camera. A link to what you bought please.

 

I couldn’t rotate the shaft manually tonight but I did bump it and took some video and pictures I’ll post below.
It isn’t as clean as the camera made it look, it has never used any coolant and it’s still full and clean now.

 

Top of the Piston, you can see the carbon better here.


You can see a piece of aftermarket coil boot that was stuck and was removed in pieces when I was first diagnosing this issue. The 360 begins and ends with that same piece of boot visible.

 

I bought it on

$40 [Dual-Lens] Endoscope Camera with Light, 1920P Borescope Inspection Camera with 8+1 Adjustable LED Lights, Semi-Rigid Snake Cable 16.5FT, IP67 Waterproof for iPhone, iPad, Samsung,Cool Gadgets for Men

Amazon for $23!
Works with iPhone and any USB C phone and has a down and side camera. For $23! I’m impressed with it.

 

On a borescope things look way worse then they are...

That carbon build up is consistent with that mileage. I've seen way worse and other vehicles with half the mileage.

The valves are open because the cams are off the base circle with respect to the valves. I.E. cylinder not a top dead center.

It is actually a good view of the valve and seat which look ok.

 

The marks on the pistons will sometimes be towards the outer edges depending on the angle of head. It is usually obvious when contact has been made, even if it was just slightly. The valves look like they are seating well when closed too. That scope is way nicer than the old Snap On I had lol.

 

I can speak for a different engine that skipped a tooth on exhaust cam and, on a different occasion, two teeth on crank. It has variable timing on both cams.

Apparently it did not fail immediately. VVT system does just that: "skips a tooth or two", so there's enough piston-valves clearance in the combustion chamber. I don't know about Denso ECU, but Bosch does a VVT check every time the engine is started to sense how bad VVT is off, and how much adaptation is needed, and whether it has to be disabled altogether. I'd expect Denso doing the same, otherwise we would see lot more dead interference engines equipped with VVT.

Speaking of VVT angle adaptations: ECU exposes these values and they can be usually read. Haven't look if Techstream can do it, though.

But I doubt you ruined your engine or even caused any damage to it.

 

I wanted to post an update to this saga. I replaced all the plugs with OEM Denso plugs. I ended up replacing the cylinder 1 and 3 coil packs with Denso packs from Amazon while waiting on my fuel injectors to be cleaned and rebuilt. Got those injectors back, and intentionally installed them in a different order than I had taken them from. Cylinder 1 injector moved to Cylinder 6 and the truck ran smoother than it ever had run for about 50 miles. Then I got a Cylinder 6 misfire and I instantly assumed the issue was with Cylinder 1 injector (that had moved to Cyl 6) so I ordered a new one from Toyota directly. Put that in and no change, the misfire remained, so I moved the Cylinder 6 coil to Cylinder 4 and the misfire moved.
12 months ago I purchased from a seller on eBay (their account is now deleted) 8 OEM Toyota Denso Coil packs. The part numbers were correct, packing looked right, comparing side by side with my OEM packs that at that time had 195K on them without issues looked identical. After 10K one of those packs started misfiring, I replaced it with one from a local parts store. Didn't have any additional issues with the truck until this incident when it was bitter cold.

Long story short, there are VERY convincing counterfeit parts being sold online. New OEM Denso coil packs and the issue is fixed. So I've got rebuilt injectors (1 brand new), new plugs, new coils and all is good.
I still need to have the timing chain tensioners replaced but that's another day and from what I understand not an emergency.

 

Yes counterfeit Toyota parts on Amazon and Ebay is a huge problem. I wouldn't even trust aftermarket part stores because the parts are trickling down from their suppliers. Buy only Toyota genuine parts from a Toyota.

Why do you want to replace the timing chain? It's just not a problem for the 3UR-FE.

 

Thanks for the update..

 

For the last 40k or so it’s made this noise on occasions (this is not my video by the way):
https://youtu.be/EDgmsNWw0XQ?si=-6ZFgsXsR7aRKYAO

It is intermittent and does quiet down right after an oil change but within a 1,000 miles or so it will happen at startup.

 

Have you tried 5W30? There are two rattle noises that people complain about. One is from lifter bleed down and the other is the oil tensioner for the timing chain on the left side (driver's). The chain has timing paint marks on it and when those marks are no longer visible then you replace the chain. It's very unlikely you would need a chain and replacing it will do nothing for the rattle noise.