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

Thanks! It definitely was a roller coaster ride.

 

I started having a little hiccup early last year (166k) and the occasional misfire along with limp mode. Scan tool said misfire on cylinder 5 so I changed the plugs and swapped out the coils to 3. Code didn’t move from 5. Took it to an independent shop and they diagnosed it as needing a high pressure pump along with some o2 sensors and wanted about $2500 for the job. I ended up finding a denso pump with the same part number on it for $250 and installed it myself. Didn’t fix the issue of course. Took it to the dealer thinking they’d know whatever it was since I struck out at the independent shop but they had it for a month and could find anything. I picked it up and didn’t get a mile before going into limp mode. That happened again and finally I had the service adviser drive the truck with me and instructed him to floor it like getting on the highway. It finally replicated the problem and he said he’d put his lead guy on it. Got a call the next day saying I need a passenger side head and two exhaust valves on cylinder three because it failed a leak down test. They claimed the valve guides were worn and that the valves were burnt. Grand total was $11k including cats for the passenger side. I declined and decide to tackle the job myself. I pulled the motor and took the heads to a local machine shop. They called the next day saying the heads and guides were fine and that there was no play. Since I already had them out, I had the machine shop clean them and grind and cut the seats and valves to be sure. I also ended up putting in new rings, Main and rod bearings as well as all new seals. got it back together and had issues with the direct injectors so I installed a rebuilt set. Still had a misfire on cylinder 3, so I swapped coils and put in another set of plugs. Still no change. Since I’d done all the previous work I assumed it had to be the upper injectors, so I replaced all of those. Better but still misfires and going into limp mode. Obviously I’m super frustrated at this point because I was about $4k in not including all my time.

Then I found a post about this and remembered hearing a rattle when I was taking the plenum off. Pulled it today and sure enough it’s just like what you guys are reporting. I took it out along with the gear in the back and the truck is totally different. No more high rpm limp modes! There is still a misfire on cylinder 3 and swapping coils didn’t help, so I’ll swap the plugs around and see if that fixes it.

this is the first time I’ve been able to drive the truck without worrying in a long time. I am glad you guys reported this and I really wish that the dealer knew more about it.

I was unable to find that bush that you talked about but it was definitely not in there anymore and not down any intake runners. Hopefully that fell out when I had the engine apart.

 

I've shown this thread to two of our Master Techs.

I'm hoping that IF we get some strange hiccup 3rd gen in..... We'll get it right the first time lol

 

Wow, that takes a lot of patience and fortitude to take a backyard deep dive like that. This is still an rare event and thankfully it’s documented here. Good luck and hopefully you have zero issues soon.

 

Geez, nice work. Sorry to hear you still have a code, hopefully that is resolved soon. Were you following a service manual or anything to just dive straight into the motor like that? Or just winging it off of past experience with engine work or something?

I like to think that if I get the P11E codes, the coolant crossover pipe leak, the timing cover leak, or anything else, I’d be capable of fixing it myself. But I need some sort of manual for that and the factory service manual doesn’t seem to be that great. But I haven’t dove into the engine part a whole lot so maybe it’s better than I expect. I just can’t stomach paying $10k for a valve fix or any of the other insanely high prices. I could buy 3 reman engines for my Jeep for that price.

 

I hear you. $11k was a lot and most of that was labor. I think alldata lists the job at 28 hours for just one head. I decided to tackle ot myself because I build motorcycle engines all the time, just not modern stuff. My cutoff is around 1980. Also there is a 3rd gen shop manual pdf I found somewhere that helped with some of the technical stuff. I wish I was more knowledgeable when it comes to the modern computer efi stuff. I’m still getting these misfires only on three, but I can’t seem to narrow it down. I’m waiting on a manifold to come in and I hope that fixes the issue. At 3k under normal load on the highway bank 1 fuel trim is about 15% higher than bank 2. At 3500 and up bank 1 goes super lean though and then bank 2 follows but not as bad. B1S2 is reading under .2 volts and bank 2 is around .4. Under 2k with normal load and they both read around .750-.850, which I believe is normal. I also ordered a maf, so maybe that’s part of it as well. I’ll report back any findings.

 

Timing cover requires engine removal. Pita

 

What exactly causes the requirement of the engine removal? I heard it was the steering rack getting in the way I think? Can that and the front diff be dropped to allow keeping the motor in the truck?

And more importantly, you DO have to remove the timing cover to get this motor’s heads off since it’s DOHC, right?

 

It's mostly about spacing for the timing cover, there are so many things in the way of it. Ideally it should only ever have to come off once during the life of the engine. But we all know that ideally and reality are two very different things...

I've seen experience master text do half an engine drop where it's only partially out but they've also got the front end and the radiator and everything else off. And yeah the steering rack and a cut and the differential is dropped too. Just depends on the truck, some guys are better at wiggling things in than others, but getting those seals on the timing cover is what's really difficult in my opinion. Especially on the back since you can't quite see it when you have to settle it in so you really have to be careful to make sure it stays seated.

 

Biggest issue I saw with removing the timing cover was that there were two M6 bolts up front holding it on that were inside the oil pan which means the oil pan had to come off. Since the diff is in the way on 4wd models, that has to be dropped as well. I already knew that my rear main was leaking, so I decided to just pull the motor to do the job. Honestly, even if it was 2wd I’d probably still pull it. Getting the gasket surface of the timing cover and the upper and lower oil pan clean enough to reseal while still inside the engine compartment would’ve been crazy difficult. Finding an oil leak after getting all that back together would’ve been enough to make me want to set it on fire.

 

update on my truck. it drove great for about 100 miles then went into limp mode again with a misfire on cylinder 3. i turned the truck off and restarted it and went for a drive. I am seeing bank 1 long term trim at around 7-10 and short term around 5 under normal load. That's not horrible, but it is way more lean than bank 2 with was -7 on longterm and 0 ish on short. under a more heavy load around 3-4k both banks are going really lean according to the O2 sensors, but more so on bank 1. I am curious if that flap being gone has anything to do with this, so I just ordered another one just in case. even with it open, i'd imagine that it would change the airflow in some way. I already ordered a maf so I'll replace that as well when it gets here. I am hoping that the misfire is being caused by that

 

Anyone know how to clock the acis gear? I just got the used plenum in but they took the servo motor off before shipping.

 

If the motor is spring loaded clock it towards the spring tension side or closed position of the flap. It is possible that is causing the lean bank 1 but we shall see soon. Good luck.

 

It's a normally closed valve, meaning that flap starts off in the closed position. You may need to take a small mirror and flashlight, and take a peek down where the throttle body goes on. Once you can see the flap, turn the gear so the flap is closed and then install the actuator motor.

 

Awesome, thanks!

just to clarify, when the motor is turned off, the actuator goes back to the closed position?

 

Yes, that is correct.

 

Thank you for this. Bought my truck used and discovered this issue. I saw your post on a FB group and just completed this replacement. I have no more issues and the truck seems to run better at all speeds.

 

I think you can find them on EBAY and they will ship to CA or if you want to PM one of the better members on Tacomaworld we dont mind re routing it to your location if you just pay for the shipping.

i have the JLT, its nice and looks like it belongs

 

Had a lube guy in the shop ask me about one a while back. He didn't know what it was, but he knew it wasn't stock lol. Good eye

 

i forgot you some guys have nazis for inspectors in that state. ours are basically a 25 dollar tax while a guy test your gas cap.