3.5 V6 ACIS plenum/manifold flap failure (2GR-FKS) SECOND UPDATE

https://www.tacomaworld.com/threads/radium-engineering-dual-catch-can-setup.765646/

 

Acis kicks in at 2600 rpms. You typically see it in gears 4 and below for AT.
In 5th, the highest I went was 2550 rpms at 100% calculated load. MTs probably behave differently.
ACIS duty cycle goes 100% at the activation point, then settles to 17%. ATs usually won't upshift to a higher gear until ACIS deactivates.

 

For those wondering about the 2nd gen taco 1gr ACIS setup. (This is for the single vvti 4.0L 1gr not the dual vvti 1gr in the FJ/4runner/tundra etc. The dual vvti has a different intake plenum without an ACIS flapper)

Its a vacuum operated setup that is actuated by a simple electric vacuum solenoid that supplies vacuum to a vacuum diaphragm. The vacuum diaphragm that moves the ACIS flap lever (all external to the intake plenum) has a spring inside of it that without vacuum applied keeps the ACIS open. The stock tune on the 2nd gens will close the ACIS (applying vacuum to the vacuum diaphragm by energizing the vacuum solenoid) only when the throttle body blade angle is above 65deg and rpms are between 2500-4000rpm (I believe, its been awhile since I have looked at the stock tune). As soon as you hit 4000rpm the vacuum solenoid is de-energized and the acis valve closes relatively slowly (over the next 100-150 rpms or so during a WOT run) as vacuum in the diaphragm is dispersed.

I dont think I have EVER heard of a failure of a 2nd gen ACIS flapper internal to the plenum. I am sure they have been failures of say the vacuum line/solenoid/diaphragm but in that case the end user would likely never know as there wouldn't be any CEL's thrown or problems running and it would just be "failed open", so just a smidge less power within that 2500-4000rpm range.

OP you got EXTREMELY lucky finding that bushing. Good looking out man!

 

I really wonder if this is happening at a statistically significant rate. Either way Assuming I don’t want a 4th Gen, I’m just planning to buy the supercharger and install it right before my 5/60k power train warranty is up. Will keep an eye on this thread for sure. Cheers y’all good luck!

 

Had the same thing happen to me this morning getting on the highway...

2017 TRDOR 4X4 Auto 84k miles
Started to accelerate on the on ramp to merge onto highway and at about 4k RPMs the truck lost almost all power, Traction control light and CEL came on and was blinking, immediatley pulled over and let it idle for 30 seconds, was rough so i turned the truck off and let it sit for 2 minutes. Turned back on and idled for another 2 minutes and seemed to be fine. Got back onto the highway and it drove normal, gave it some gas and got up to 5k rpms and felt fine no power loss. Going to check to see if i can read any stored codes when i get home today. Hopefully was just a weird hiccup.

 

It'll be interesting to see whether this issue turns into a TSB w/ extended warranty replacement. Or maybe even a recall?!

 

Maybe but doubtful. It's not really an issue that comes through the dealership lines. But Toyota are also aggressive with recalls so even a few hundred notes would be enough to recall 2 million trucks.

 

I very much doubt it. Theres only been a handful of reports here.

 

I’d be curious to see if the actuator draws more current as the flapper starts to go.

 

I'd pull the actuator and check that gear.....I'd put money on it being broke. The fact it didn't do it a second time is probably just luck. Engines don't "hiccup" like that for no reason. If it's broke, you have to remove the upper intake to remove the flap, but more importantly to check the intake runners for cylinders 1, 3, and 5 (passenger side). There is a small bushing that can fall out of its spot once the flap is broken, and it will fit down the intake runners and reach the top of the valves. I made an update to this post in the thread, where I did find that bushing and removed it....check that reply and photos out to see what I mean.

 

I would probably assume it would be less current, as the load of rotating that flap is now gone. With no resistance against the motor, it's current load would probably drop to almost nothing.

 

Ship it to me (or someone you actually know out of CA) Ill ship it to CA for you.

 

I was thinking prior to that - if it binds up before it snaps.

 

Thats why I was wondering about monitoring it via OBDII. Think I recall reading it was PWM so if it binds up, either open or close, Id imagine you would see a change in that command

 

Could you get your truck to go into limp mode everytime you got up into the RPMs? Or was it more sporadic? I scanned for any CEL codes when i got home and found nothing. Drove it normally this morning on the highway without issue. Idles and shifts normally. If it happens again ill rip the manifold off and take a look, just got 3 feet of snow so hopefully dont have to do it soon...

 

Nope, it was hit and miss. I had to get into the throttle several times to replicate the issue enough to get it to finally throw a misfire code. Like you said, it was very sporadic and random.

 

UPDATE No. 2!

So I noticed my truck, since the whole intake deal had a slight "stutter" while running, particularly at idle but every now and then, when I pulled out from a stop. I've dealt with enough misfires to know that it was a single miss, sporadically and randomly...and it would only miss once, maybe twice.

The other day, I got into the throttle really good, one of the first times since I replaced the intake...and boom, check engine light....P0301 - Cylinder #1 misfire.

Now if you remember my previous posts, I swapped #3 coil with #1 coil in diagnosis to eliminate that from the equation. Turns out....heavy misfire, like what was caused by the intake port being blocked, caused the ignition coil to overheat due to spark going directly to ground....and it damaged the coil windings. So it wouldn't misfire all the time....just once it started getting hot, or under heavy load.

I just replaced that coil, and it's gone. No stutter, or hesitation....and it seemingly revs up smoother too as well.

So another note to keep in mind for anyone that has this intake issue, whatever cylinder starts misfiring heavily from being blocked by the loose ACIS butterfly, you may have to replace the ignition coil as well....because it apparently doesn't take much to overheat and cook the windings in them.

I replaced mine with a Denso 673-1311, which is a direct manufacturer replacement for a Toyota 90919-A2008 coil, which is made by Denso. They are the EXACT same coil, right down to the E11-10R-04-8610 molding number on the top of the coil.

Toyota wanted between $145 to $125 for it, McGeorge Toyota wanted $83.....and I got the same exact coil, minus it saying Toyota and coming in a Toyota box, for $54 on RockAuto.com

Both are manufactured in Japan, by Denso. One just has Toyota laser etched into it, with their part number...and that's where the high cost comes in. Toyota tax!

I also checked the spark plugs too, and they are fine, being they only have 30k on them so far.

 

This man is wise

 

Do you have a tune? OTT?

 

Great job diagnosing this on your own! I hate when one job turns into multiple. I will add this on my list of things to check/listen for on this truck. Lma