4.0L Timing Chain tensioner, P0022, OCV, VVT Solenoid

525,000 miles, original owner.
I'm chasing down a P0022 code so I wanted to check the timing chain tensioner first. From what I gather from the pictures I took, it's not too far extended, right? If I am correct, the likelihood of the chain being stretched and skipping teeth is highly unlikely. Oh, the truck has never overheated, which from what I understand is about the only thing that will stretch one of these chains, right?
I look forward to the opinions of others more knowledgeable than me.

Next, I figure it might be time to replace the Oil Control Valves(OSV). I realize P0022 relates only to one side but with the age and mileage I might as well do both. I replaced the OCV screens about 45,000 miles ago (August 2022) when P0022 first appeared and it wasn't until a few weeks ago the code reappeared.

 

Doesn't look like it's out very far so that's good, looks kinda cruddy in there though so you may want to check the VVT screens.

 

I agree it does look rather nasty, but at >500,000 miles it is to be expected.
VVT Screens also probably look pretty bad compared to that image of the tensioner.
You may want to use a quality engine flush / cleaner.

 

525K miles on the original engine? Well done.

As I understand it, the nature of a dual-bank VVT system driven off a single chain means that over the long term (which 525K miles certainly is,) one side will preferentially wear more than the other due to timing chain stretch. If need be I can dig up the youtube that carefully explains this fine point.

Pls. share some additional details for those of us aspiring to make it to 400-500K+ miles on the 1GR-FE engine:

- What brand/weight of engine oil & what type of oil filter do you use?
- What is your OCI (oil change interval)?
- Ratio of highway to city miles, i.e. 50/50 or something much more highway-oriented?

 

so you don’t wanna condemn any parts, at 525k on a sludged carboned motor that looks like it never had an oil change

a German car would be getting timing chain and tensioner done by 100k.

 

For the first 450,000 miles or so oil change intervals were 10,000 miles, always synthetic and for a long period of time much taller filters. When I replaced my valve cover gaskets and saw the buildup of burnt up carbon in the heads, I switched to 5000 miles and Toyota Y3 filters and will never recommend 10,000 to anybody. It’s probably 90% highway I used to do 30 to 40,000 miles a year now it’s 20,0000 to 25. Original engine and trans. To suggest I never changed the oil is not accurate

 

500 000 miles honestly it’s time for a new ride

 

With 525K on the engine, It wouldn't surprise me if it was the OCV.
Even more so, since you replaced the screens not too long ago.

The OCV has failed in some engine. And judging by the condition of the tensioner "color", I suspect that build up isn't helping the OCV.

I will say, That's not as bad as I'd expect for an engine running 10k mile oil changes.
Still don't recommend it. (Like you said)

 

Doesn't look stretched, do the solenoids. I had one start getting sticky at 135k.

 

Yes

 

Ah-hah, here's our answer to "how did that dude get >500K miles?!"

Highway miles are easy miles.

 

[QUOTE="GilbertOz, post:

Highway miles are easy miles.[/QUOTE]
And yet,

"When I replaced my valve cover gaskets and saw the buildup of burnt up carbon in the heads"

 

Seafoam does a pretty good job on the sludge, pour in 1oz per qt of oil, I put it in 1000mi prior to an oil change. I noticed a positive difference in the way the motor ran within 100mi of putting in the seafoam. Running-wise it had more of an impact then replacing spark plugs or cleaning the MAF sensor. Idles smoother and quieter, of all the typical maintenance stuff it's had the most impact on how the truck runs compared to any of the other normal maintenance items. The difference wasn't night and day but it was easily noticeable and felt.


Regarding the timing jumping a tooth, you'll know it the second it happens, the power will drop significantly, it will rev slowly and barely idle if at all.

 

Bro.....I'm just impressed you got over a half million miles!

 

Thanks, sometimes it surprises me too

 

I wish I had more to contribute here, but I do want to note per your original post that the timing chains absolutely stretch over time, that's why there's so much take-up in the tensioner. At 525k I would also expect that the timing sprockets are well worn, and the plastic chain guides are worn down to hen's teeth and also very possibly in multiple pieces, held mostly in place by the chain and the two small alignment tabs that hold them to the cast fittings. Your VVT cams may also be due for a replacement.

All that being said, bravo on 525k and I am a huge fan of these engines.

 

Yeah once a Tacoma passes 500K on the original engine you have to sit back & change attitude to, "I got my money's worth and then some, every remaining day is a gift, not an expectation.."

 

Is there another “cam sensor” on the front side of each bank? Maybe something to do with magnetic? I don’t recall seeing anything but I wanted to be sure
I’ve read here in other posts about “cleaning the cam sensors” but I also read the OCVs/VVT solenoids are the same thing that some refer to as cam sensors.
Thanks

 

There are VVT cam assemblies on the front of each bank, under the timing cover. They are not simple gears but rather are quite complicated and have internal parts, and like the rest of the timing system wear with use. Your P0022 can certainly be caused by timing issues.

This thread is regarding broken phasers (the little propellers on the front of each cam assembly, which are used to sense the VVT cam position) but does give some understanding of the parts in question, where they are, and what they look like.

https://www.tacomaworld.com/threads/broken-vvt-phaser.731861/

 

Thank you for that explanation