2018 popped a DTC code P11FO

I have seen the crank test done but never used or performed that test myself. All the tests that I have used were a running cylinder cut out test that was automated. I saw a test that was names similarly in Techstream while I was familiarizing myself with it the other day but didn't try it out.

I work in a private commercial fleet with dealer level access to OEM. Our equipment can't simply be returned to the OEM for warranty repair. Yes warranty hurdles can be extensive and multi-layered. A single test is never used to prove a fault.

 

Thanks everyone for the inputs, I feel wiser just reading through the various methodology spoken of.

One question I had wasn’t answered.

Is their any variable I as the driver could have in this issue? I don’t abuse the truck, and drive it like the old man I am, lol.

 

No, this is luck of the draw. Nothing that you could have done differently.

 

Imo, nah.

 

If it does end up to be an exhaust/intake valve leak.( Couple other things can cause it too, sometimes even a spark plug not tight enough).
Then no probably not, not a dam thing you could do to prevent a manufacturing machining error.

It is generally caused by the valve stem being at the wrong angle relative to the valve seat or being off centre. Over time carbon builds up on the valve seat and/or blow by burns the valve and or the seat the the point that the computer can't correct for it or it goes outside of it tolerance parameter and throws the code.

Sometimes "babying" an engine is not always the best thing for it.

Short trips are bad. In some engines babying it all the time can cause problems in the long run.

I forget which engine it was. But it had a similar problem in that carbon was getting into the valve seats then a valve would burn through. (not the manufacturing prob with the valve stems everyone has that problem area)

Upon studying it it was found that the best thing to prevent it from happening was to rev the shit out of the engine every once and a while, not only did it help to remove carbon,
but at high rpms the valves "float" and will rotate.

If it is the valve ,on the ones I've seen with this before the spec compression test is something like 199psi but I've heard of as low as 180 being ok, but the bad cylinder drops to 90-120 so they will see 90-120 on you #5 cylinder and then over 180 on the next cylinder they test, no use testing more.
As mentioned above, Toyota will then want a leakdown test performed. They pressurize the cylinder with shop air and measure the time it takes to drop. At this point they can use a screwdriver or stethoscope and will be able to hear where the air is leaking out of.

Here is a pic of a 3.5 head that had the same air/fuel code.

This one was the intake that failed,
top two is the bad cylinder, take a look at the centring of the valve stem hole relative to the casting on the bad valve vs the pig of the "happy cylinder" on the bottom.

 

It's interesting how the carbon is accumulating on the opposite side of the injector. The fuel cooling rapidly and not burning completely when it touches the cylinder head. Might have to take my truck out on the highway and treat it like a rented mule to make sure to burn some of that off!

 

Yeah after seeing these I give her the beans every once in a while just in case. As well as go on a long drive every once and a while if I've been making a lot of short trips. And injector cleaner a couple times a year when I think about it.

Ive been surprised too on the amount of crud especially on the intake side.... even on the "good" cylinder. I thought port injection cleaned most of that out....

Purely conjecture on my part, no analysis done in any lab and the idea came to me with a beer in my hand. So take it with a grain of salt....

Venting the engine vapours through the intake manifold, worked quite well with the older dino oil as it could burn off quite cleanly,
Newer Synthetics do not burn off as well...
Combine that with Tacomas ingesting oil though the EGR system when it is somewhere over a 20deg angle and you have a recipe for deposits.
Especially when people are smoking then hydrolocking their engines after idling on a really steep hill for too long.
So after a couple more beers I ordered an oil catch can and installed it.
I can confirm that it helped with smoking on an incline, will it help with long term deposits ... no idea.

 

If it's valve, a leak down test will show leak into intake/exhaust and rings will have leak into crankcase. Any mechanic worth a damn should have no issue identifying leak source.

 

There are times where this test can be inconclusive and a visual inspection was needed to confirm cause. 2 times I have experienced this are on a new rebuild with a cracked ring. And a natural gas engine that had a cracked piston. The cracked ring burned oil, passed compression and leakdown. The cracked piston failed compression, but technically still passed the leakdown. It wasn't consistent with other cylinders. During compression the crack would open up under the pressure of compression but under the leakdown would pretty much seal back up. Running a borascope down the hole found the hairline crack.

 

Thanks

 

Yep LOL you can never give an absolute answer on how to find the same problem on a different vehicle.

Intermittent problems are the worst. Can drive an excellent tech nuts sometime figuring out what the right combination was to duplicate the problem is. And most customers suck when it comes to giving enough information to even figure out where to start.

One that made me laugh years ago was " Customer states that the car is "farting" very loudly but not sure where from, insists that it sounds like a fart and wants it fixed as it's embarrassing " , so after all the Taco bell jokes poor buddy is doing everything imaginable to make it fart. Checked all vacuum lines, Did all sorts of things and drove it around a couple hours trying all sorts of weird things, blew compressed air on the underside looking for farting holes, gave up. Thought to try it the next morning when it was cold.
Filled the car up partially with gas , put it in the back lot.
Went out a couple hours later,
what's he hear,
braaaaaaaaaap, couple seconds later braaap so he's running around the car trying to figure out the area.....
Opens up the gas fill cover,
Sounds like the gas cap is farting, WTF.
First thought leaking gas cap, ratchet it a little tighter.... braaap,
Unscrews the gas cap,
Looking at the anti spill flapper at the gas tank fill port and hears a little braaap, and you see the little flap buzzing back and forth.
Bright guy, whipped out his phone and filmed it. Got a last little braaap, lol you could hear him laughing and thanking Jesus in the background.
And yep it sounded as best described as someone failing to sneak one out on a vinyl seat.
Lol it was the purge valve.

I got the story when we were having a few beers and was bragging about tracking down different issues by sound,
talking about the different terms we were using for buzz, squeaks ,rattles, ticks, tocks, screeches, squeeks, sucks, wheezes, etc.
He comes holds up his phone hiding the screen and says "Oh yeah smart guy, what's this" and plays the braaap . "Yes this is legit, you'll know when you see the video, but figure this one out"
Oh my ribs were so sore from laughing my ass off. I would have never guessed that in a million years.

 

Update: Dropped truck off at dealership Sunday and got the results from testing this evening. Bad intake/exhaust valve (s) and will require new head and replacement of all bad parts. Stated covered by powertrain warranty. Also stated that this is a known issue with Tacoma’s.

Anybody else hear of any trending of this issue with Tacoma’s?

Will be talking to corporate tomorrow about issues and see what their response will be.

 

JAL,
I also got P11F0 obd code on my 2018 Tacoma SR5 4x4.
9 months ago I took the beast in for a recall to replace the fuel pump. I think I had 45,000 to 50,000 miles on it.
I originally got the code at 65K and didn't want to take it to the dealer without knowing what the code meant.
So I took it to a toyota repair shop and the mechanic scanned it. He said the code meant that there was something wrong
with the head and that this same problem also occurred in corollas about 10 or 15 years ago, but not in tacoma's at that same
time. He said that the corolla's armature would vibrate awkwardly and damage the head. I guess the issue now appears
in Tacoma's.
I hope you find something from corporate.
Thanks for listening.

 

ny further updates on this thread??

 

I have the same issue on my 2017. Issue first appeared at 60100 miles. Just out of warranty, dealer claimed they performed compression test and leak down test but when I asked to see results they couldn't provide them. They said they just need to reaplacw the head cosr was going to be 6k. Called corporate they told me all they could do was give me a 10% discount. Took to mom and pop shop, they said compression numbers were correct. They did a boroscope inspection and found some carbon around valves so ran some fuel system cleaner. That cleared the code but still comes back every once im a while. Truck now has 79k miles. Just extra info, scan shows that the misfire only happens at idle, but don't have a rough idle or loss of power. Google search makes it seem like this is know issue and it happens are various mileage.

 

My new to me 2018 with 90,000 miles does it too. I had compression tested and it was OK. Bought an OBD reader that can clear the code on the run so cruise control will work. I have been running fuel treatment and just installed an oil catch can. Hopefully that will eventually stop it. Otherwise, no issues.

 

The codes on mine are permanent so even if I clear with obd scanner it still remains im background.

 

I think mine remembers it but doesn't keep the dash light on. Does yours cancel the light and let your cruise work?

 

it clears the light and lets cruise control and traction control work

 

I see I didn’t come back to give final update to my original issue.

A little time has pass so I’ll do my best at remembering.

Once they order parts and I dropped off truck it was in their shop exactly 30 days. They were insistent on me picking up before closing time or else they would park outside the bays

Picked up that evening and after leaving went across street to a fast food place. While in the drive thru I noticed AC not working. After parking and eating it still was working so drove back to dealership.

They claimed after 2 hrs waiting they had serviced but it must of leaked. Re-serviced and finally on my way.

it drove alright but the thoughts of “what else” or “what if’s” played on my mind.

This was during Covid late 2021 and used vehicles were being offered good amounts so I worked a sweet deal for a 2022 Tacoma OffRoad.

I’m right at 45,000 on it without issues