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

16-19 if you have the Toyota app it can use you cell phone to send data back to toyota. The 20+ trucks can do this on their own since they have cell connection built in. I'd assume Toyota could use that if they wanted to gather data?

 

It's not a video game. It only sends basic data like speed and stop events and stall events and things like that. DTCs are uploaded... It doesn't automatically know if a piece of plastic cracks.

 

But YOU'LL automatically know when that piece of plastic breaks..... because when that flap suddenly isn't where it's supposed to be, and is where it's NOT supposed to be......let just say, things will start to get exciting, lol. Limp mode can be quite a bit more violent than the name actually suggests.....

 

Been there before in a Pontiac.

She went to limp mode alright... After sending a rod to the moon

 

Oof.....yeah, you'll notice that, haha

 

Whelp... chalk up another intake plenum ACIS broken flap "catastrophic failure."
*2017 TRD/OR with 77,000miles*
Driving up an on ramp to merge into freeway traffic, and suddenly have a total loss of acceleration, dash lights up with all the CEL goodies, and truck goes into limp mode. So I take it to the shoulder, turn it off and wait a couple minutes. Start it back up and CEL's disappear and truck is running/idling normal. Start getting up to speed to merge into freeway traffic and about 20-25mph it goes back into limp mode with CEL's, so I pull back to the shoulder. I'm a little stumped because the truck seems to idle fine, but won't drive over 20-ish mph... Tow the truck to my house, log on to this very thread and the "2016 Tacoma in limp mode, FIXED!" thread, and bingo!

Followed the advice here on intake plenum removal (thanks to JohnnyTRD06 !!), opened up the ACIS actuator, and found the worm gear/flap axis to be flopping around and totally disconnected from the rest of the flap still inside the plenum. The flap itself had not yet dropped into the intake, but the end had snapped so the flap was just chilling in "forever-closed" position, starving the intake of air needed at the higher rpm's (but still idling fine). No flap/parts were dumped into my intake valves thankfully (I inspected same carefully).

Incredibly, same day day/locally I was able to find a used low mile (20k) intake plenum with actuator/flap/etc all clean and intact (I opened the actuator cover and checked) for $240.
While I had everything opened up in the engine bay, I replaced the spark plugs, put dielectric grease on the coil packs and other electrical connections, deep-cleaned the throttle body, etc. Reassembled everything, fired it up, took it for a drive last night and all codes are gone... it actually runs noticeably smoother than it did before the ACIS flap failure, likely due to new sparkplugs and cleaned up TB.
If something were to fail down the road with this new plenum, I'll just rip the broken flap out of my old plenum and run that with the flap delete.
>> Anyone have advice on HOW to get the flap out of the plenum?? Mine is still mostly intact in the plenum. It is broken, but not yet loose/rattling around. If I can dislodge it, will it drop out through the throttle body hole or one of the intake ports? <<

I wanted to express my appreciation for this group / this thread... I would have struggle-bussed the crap out of this one had I not found this. Instead, I was down for only 2 days and out $240. Winner, winner.

(I'll offer one small piece of info that I scoured for here but couldn't find super clearly: if for some reason your actuator gears get disassembled and you're trying to ensure assembly gets re-aligned for correct "clocking" of the flap and gears - the 'engine off/plate closed position' is a full counter-clockwise turn of the worm gear... ie: turn worm gear counter-clockwise and flap should be in closed-position, then re-install cover. When it actuates under higher rpm load, it will turn clockwise, opening the pos flap, then back to counter clockwise for closed/low rpms. It's been said in different words but didn't indicate which way the gear should be turned on re-assembly. Minor detail, but might help somebody.)

 

Interesting thread

 

Found mine today. Fell apart on the way home, cylinder 1 misfire. Removed the gear, flap and shook out the bushing. It been bouncing around the intake. Put it all back together without it. Truck runs fine without it. No codes, very smooth through the rpm range. Truck has 81,000 miles. Also did plugs and replaced coil #1 since I already ordered spares anyway. BE SURE TO GET THAT BUSHING OUT!!!

 

Get all the parts out, reuse the intake. No codes without these parts.

 

Just curious: What are the effects of an ACIS flap delete on torque / power at various RPM ranges, and what are the impacts on gas mileage?

I'd expect less torque and possibly lower mileage due to the non-optimal length of the intake in the lower RPM band where the ECU is expecting the flap to be closed.

 

Not sure, I have 33's and 5.29's and I tow my camper with this truck. I just fill it up when it needs it. Camper is a 2022 E-Pro 20bhs.

 

Not 100% apples-apples but here is one 3G (same truck/same day) on two different calibrations. One with "normal" ACIS operation and another that does not utilize ACIS where it's resonant benefits are observed. For this comparison, I'd only look at the data below 4K RPM, as anything after that would not be related to ACIS operation or lack thereof.

There is a pretty substantial torque loss without the ACIS system.

 

This proves the lackluster power when I drove it without the flap in there. I did do that for a few days, but it felt lethargic in throttle response and I found myself putting my foot into the throttle more to pull out and even just when driving around town.

 

What position is the ACIS flap in with the engine off or if you unplug the connector? Would this leave it in low speed high torque mode and not have to worry about the flap breaking? I realize it would suffer at higher RPM

 

I'm pretty sure engine off / connector unplugged = ACIS flap closed. It doesn't open until higher up in the RPM band.

If it's left unplugged & closed all the time, certainly upper-half-of-RPM-band power & possibly fuel efficiency are going to suffer somewhat.

While no doubt the active cycling (open/closed) contributes somewhat to the metal fatigue which seems to eventually shear off the shaft, I wouldn't be surprised if just plain vacuum/suction cycling from the intake itself also contributes to fatigue, in which case a disconnected ACIS flap might eventually break off anyway.

 

I'll take a couple less hp in the lower rpm range knowing that my intake will never dump parts into my engine. 5.29's took care of any lack of acceleration. This isn't my daily, it's mainly used to pull my camper. My daily gets around 10 mpg anyway and is much slower.

 

2016 TRD Off Road Manual Transmission Bought New
Probably around 30,000 miles towing
130,000 miles CEL for cyl 2 Air Fuel Ratio Imbalance.
Found ACIS gasket damaged and failed leakdown test on Cyl 2/4.
Ran for appx 2k additional miles with no issues other than CEL on before trading it in.

 

Man, you thought I was griping about $600 bucks for that intake.....you should have heard me when I had to shell out $12,868 to put an engine in my truck because it suffered a valvetrain failure at 100k and sent cam follower needle bearings into the oil pump, and then wiped the bottom end out.

 

So did you have both ACIS and valvetrain failures on the same engine?

 

You wonder why they didn’t put this valve in the exhaust . At least no worries of parts going into the engine .