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-   -   Timing chain nightmare (https://www.toyota-4runner.org/4th-gen-t4rs/274664-timing-chain-nightmare.html)

wbailey 06-30-2019 09:43 PM

Timing chain nightmare
 
See if you can crack this:

About a month ago I got a code p0012 bank 1 overly retarded timing. Swapped OCV valves and it the code jumped sides so I replaced it but still had the code...weird. Opened the valve cover and found a loose cam chain where the tensioner had failed. The primary tensioner was extended (but not by a lot) and at TDC the cam marks were off by 1/2 a tooth.

Ordered a chain set and replaced everything but couldn't get the marks to line up, they were off 1/2 tooth with the painted links right where they should be on the sprockets. I don't know if this is NORMAL but with the gears lined up I would install the chain and have a little slack between the bank 2 cam and crank, if I rotate the crank to move the slack into the tensioner side, the crank advances ahead of the cams and I'm back where I started 1/2 a tooth off. Heres a drawing of how I set it, I did not skip a tooth.
https://i.imgur.com/PT7XWhC.jpg

I figured maybe the VVTi makes micro adjustments to the cams to accommodate a few degrees and sealed it back up. Cranked it. Drove it. Still had retarded timing.

opened it back up and redid the ENTIRE process, I even held the crank in place and cranked the cams back by hand to get the chain TIGHT and it still wouldn't line up. there is no way to take the extra slack out without retarding the position. Was I sold a used/stretched chain? The tensioner isn't wayyy out like it would be on a stretched chain. How can an unstretched chain be off by 1/2 tooth?!!


Pics showing the out of time gears
1gr fe - Album on Imgur

waypoint 06-30-2019 11:48 PM

1 Attachment(s)
Your drawing is wrong. Bank 1 intake cam sprocket does not align w/ the raised timing mark on the bearing cap at 12 o'clock. It aligns with the indented timing mark located to the right of the raised timing mark. If you aligned the intake cam timing mark wrong, there's your 1/2 tooth error on the exhaust cam.

See pic below from mine:

wbailey 07-01-2019 10:18 AM

Quote:

Originally Posted by waypoint (Post 3314534)
If you aligned the intake cam timing mark wrong, there's your 1/2 tooth error on the exhaust cam.

Sorry if the drawing was confusing, I did align Bank 1 to the indented mark on the right so it must be something else.

djpope09 07-01-2019 12:51 PM

I found the easiest way to get everything lined up was to remove the camshafts and re-set all the chains/camshafts at the same time. It's more work, but it made more sense to me that way.

The FSM has a section for measuring the chains to see if they are stretched. You could do that if you think your chain is too long.

How do the rest of the tensioners look? Are any of the guides worn down?

spartacus 07-01-2019 01:44 PM

this video might help
YouTube

waypoint 07-02-2019 04:07 AM

OK, this is a good troubleshoot so let's dig in starting from the original problem:
"About a month ago I got a code p0012 bank 1 overly retarded timing. Swapped OCV valves and it the code jumped sides so I replaced it but still had the code"
1.) The initial symptom was P0012 with factory components. How many miles on the engine at that point?

2.) The OCV experiment: they are not readily interchangeable between banks given the mounting bracket angles, so explain the "swapped OCV valves" process. New OCV installed on bank 1?

3.) The result of the OCV experiment: explain the "code jumped sides" outcome in more detail. What error code was set?

wbailey 07-02-2019 10:07 AM

Quote:

Originally Posted by waypoint (Post 3315199)
OK, this is a good troubleshoot so let's dig in starting from the original problem:
"About a month ago I got a code p0012 bank 1 overly retarded timing. Swapped OCV valves and it the code jumped sides so I replaced it but still had the code"
1.) The initial symptom was P0012 with factory components. How many miles on the engine at that point?

2.) The OCV experiment: they are not readily interchangeable between banks given the mounting bracket angles, so explain the "swapped OCV valves" process. New OCV installed on bank 1?

3.) The result of the OCV experiment: explain the "code jumped sides" outcome in more detail. What error code was set?

1. 185k miles
2. I swapped the valves after seeing it on another troubleshoot post, they fit real snug but I had them twisted because of the brackets and not bolted in.
3. code p0012 timing retard bank 1 became a p0022 timing retard bank 2.

Since it will come up here's a pic of the original tensioner before I replaced anything.
p0012 - Album on Imgur

waypoint 07-02-2019 10:25 AM

Quote:

Originally Posted by wbailey (Post 3315256)
1. 185k miles
2. I swapped the valves after seeing it on another troubleshoot post, they fit real snug but I had them twisted because of the brackets and not bolted in.
3. code p0012 timing retard bank 1 became a p0022 timing retard bank 2.

Since it will come up here's a pic of the original tensioner before I replaced anything.
p0012 - Album on Imgur

Thanks for the tensioner pic, looks like it was extended by 1-2 ratchet clicks but not likely enough to account for the original problem.

Your other pics showing timing marks do not indicate a stretched chain...this failure shows more timing retard on bank 1 than on bank 2 relative to the crank position, as there are more (worn) links acting on bank 1 given the longer distance from the crank. Let's take the chain and your installation off the table for now and assume they are correct, and that the static chain slack accounts for the retard you are seeing at the intake cams.

Swapping the OCVs was a good experiment and would seem to have indicated the OCV was the problem. But P0012 is still happening with the new replacement OCV, correct? And other than the check engine light, does the truck run well?

If P0012 is your only current symptom, here's what I'd do:

1.) Remove and clean or replace the OCV filter on bank 1 if you haven't already. Get a new crush washer from the dealer to ensure good sealing during reinstallation of the filter and plug. Report your findings when you remove the current filter.

2.) If the OCV filter doesn't correct the problem, I'd remove the intake cam actuator/sprocket and replace it. Not cheap for a Toyota part at $170 or so, but it can be done without removing the main timing cover (again). I did mine early in my project, had to buy a 17mm offset box wrench at Sears and a 24mm long open-end wrench to hold the cam without slipping off as the crescent wrench did.

waypoint 07-02-2019 10:29 AM

Also, if you don't have the shop manual diagnostic procedure for P0012 and related codes, here's a link:

https://www.customtacos.com/tech.old...ta/0050013.pdf

wbailey 07-02-2019 10:43 AM

I checked the filter and it wasn't clogged, really the whole engine is rather clean for the miles.

It runs, but not well, poor mpg, the idle is a little rough and sounds like a tractor, I thought about the intake cam gear because of the sound. Like if the hydraulic pressure wasn't building and the lobes were just rattling inside the gear housing. But the way the gear is assembled it doesn't seem like it would cause minute slack in the primary chain, am I over thinking?

EDIT: regarding other DTCs I have a p0420 but that's been happening for 2 years and it drives ok, sometimes it would clear on it's own.

08TxRunner 07-02-2019 12:46 PM

I'm really questioning your OCV swap. The OCV has holes and passages down the sides that match up with holes/passages in the bore where it is mounted. That allows the proper pressure/bleed down of the VVT system for that bank. If you just swapped one side for the other and 'twisted' them, I can't help but think those grooves and holes are misaligned. You really ought to buy two new ones.

LH Dorman: 917-231

RH Dorman: 917-238

I've been running these for about 2 years with no problems.

https://i.imgur.com/RWGa8t1.jpg

wbailey 07-02-2019 01:25 PM

I agree, the OCV swap was not a good test, I just did it because it was easy and recommended on another forum. I replaced the bank 1 sensor and still get the code so it's on to the timing gear.

is there a way to test the gear without removing it? I just tried unplugging the ocv to see if it made a difference in sound as seen in this video
YouTube
but it stayed the same.

08TxRunner 07-02-2019 02:25 PM

Is it possible everything is working fine except you have a bad cam position sensor? If the chains line up as you've said, the OCV's and filters are known to be good - what else could it be? Scratching my head.

Also, how did you determine the screens weren't clogged? They may not have trash in them, but a scaly substance that is not real apparent unless you spray one section of the screen and hold it up to the light.

waypoint 07-02-2019 03:08 PM

Quote:

Originally Posted by wbailey (Post 3315281)
I checked the filter and it wasn't clogged, really the whole engine is rather clean for the miles.

It runs, but not well, poor mpg, the idle is a little rough and sounds like a tractor, I thought about the intake cam gear because of the sound. Like if the hydraulic pressure wasn't building and the lobes were just rattling inside the gear housing. But the way the gear is assembled it doesn't seem like it would cause minute slack in the primary chain, am I over thinking?

EDIT: regarding other DTCs I have a p0420 but that's been happening for 2 years and it drives ok, sometimes it would clear on it's own.

The actuator/sprocket assembly has a lock pin which is unlocked by oil pressure when the OCV first opens. With the engine off, the pin should extend under spring pressure and mechanically lock the VVT actuator vane to the sprocket base.

You should be able to test the lock function by rotating the intake cam (wrench on locator flats) back and forth a small amount while observing the sprocket. If the cam moves independently of the sprocket, the lock is not set and is suspect.

waypoint 07-02-2019 04:29 PM

Also, here's a thread on P0022 and rattling noise resulting from problematic VVT actuator/sprocket (among other things you've already replaced):

The VVT-i Death Rattle on Start-up: TSB? - Page 7 - Toyota FJ Cruiser Forum


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