Ok, Back story is i was headed to work on the highway came up to a hill and randomly the truck downshifted and the dash lit up like a Christmas tree with flashing engine light and all the normal other lights. It still ran but only at certain RPMs and once down at idle stumbled and hard to get going. Kinda felt like it was running on 4 cylinders. Since nothing was knocking and i was only 3-4mi from autozone and home off i went to get the codes read.

Outcome of the code reading was primary code P0021 Bank 2 timing over-advanced or system performance. Also with a gang of other codes but the other associated P0018 Bank 2 crankshaft to camshaft correlation. Guy at autozone proceeded to try and sell me a timing belt.... the car is F---ing running still. thanks bud...

Get her to the house and proceed to check the timing by opening the cam covers and this is what I find the Right bank #2/passenger side is 4 teeth off!

So proceeded to rip it apart like a timing belt and cant find anything except this slightly greasy stuff on the gears and the belt pretty slick.

I think it was from spilling a bunch of coolant when i changed out the water pump outlet gasket earlier in the week due to leaking. it got all over the belt and then 3 days of running i think the glycol in the coolant reacted with the belt friction and made this greasy solution. So 6hrs later all cleaned up and belt and gears with cleaner and what not shes back to running like a kitten.

Figure this would help others as the few posts on this subject noone ever comes back to say what the fix was.

Z

Wow, click bait headlines have made it to free forums

Always helpful. As I was reading it I was thonking you slipped a tooth on the timing belt . Glad you fixed it.

You clicked...

You should be able to run your belt as greasy or wet as you want to and it not jump. Sounds like you have a bad timing belt tensioner.

I hope you don't, but I've seen vehicle with oil and coolant on their T-Belts from leaks and no slipping.

I agree with you honestly, I did still have my old tensioner and swapped it just in case but when I recompensed the one that came.out it seemed the same.tension.

It was really slick compared to a dry clean belt gear setup.

4Runner owners, fix your timing belt with this one simple trick mechanics don't want you to know about!!!!!

Did you make sure that when you installed the belt that the camshaft didn't rotate by itself? This can happen sometimes as the camshaft can be under load, there's also an additional step to VVTi 4.7L engines to help reduce the camshafts popping out of place on you.

How much coolant are we talking about on the timing belt? I would be a bit cautious since I've always been imparted that coolant and oil will degrade a timing belt.

Yeah I've read a lot about coolant and oil degrading belts to 10% of total life etc etc.... eh this belt had about 2k miles and after a dawn dish detergent wash looks/feels new I'll take my chances.

I'd say a good 1/2 gal on the belt it was WET as I didn't drain coolant and just pulled the waterpump output off and let it dump. Should have drained first, oh well.

You'll have to expand on HOW the cam can rotate by itself since like I said it was 4 TEETH off not self rotated but still showing in time...? Little confused by that statment.

Z

Sorry, you're right; I'm thinking of a different VVTi set-up not related to the 2UZ-FE. The additional step is meant to help unload the camshafts and doesn't have to do with the phasers like I had erroneously recalled. IF you did have the cam rotate on you it'd be about a tooth or two maybe and you'd know if it was done wrong from the get go as it wouldn't run as well.

I'm gonna have to go with the tensioner possibly failing as it'd be the only thing able to give enough slack to skip a bank like that.

Did the codes clear? You can get those codes when the VVT-i solenoids go which they can and do on the V8.

I read when researching that can happen with bad or stuck solenoids as well, seemed those people didn't have any noticeable running issues or CEL just the codes if they randomly checked. I did go there first as its easier and pulled the #2 bank actuator and everything was within spec ohms wise and the valve moved freely without any noticeable trash or binding in the valve or valve body.

Here is the list of original code readouts.

P0021 Camshaft position "A" - Timing over advanced or system performance (Bank 2) -------- This is the passengers side head FYI
P0300 random/multiple misfire detected
P0301-8 these were all 8 cyl misfire detects
P0018 Crankshaft Position - Camshaft Position Correlation (Bank A Sensor A) ------------ this is the associated fault leading me to the belt skipping teeth
P0101 Mass or Volume Air Flow Circuit Range/Performance problem
P2196 Oxygen (A/F) Sensor Signal Stuck Rich (Bank 1 Sensor 1)
P2198 Oxygen (A/F) Sensor Signal Stuck Rich (Bank 2 Sensor 1)


After 50 miles and plenty of romping on it to get fast RPM changes etc no issues, CELs, or codes and purring like a kitten.

Z