2012 v6 at DCSB engine knocking @ 1500 rpm

Any more news?

 

News? Sure my wife wants to trade the tacoma for a 335i! Im thinking a yes on that one!

 

My 2013 has the exact same symptoms as the OP's Tacoma. I have always run 87 octane in mine. It used to happen pretty rarely but now I'm noticing it more. Could be that I've been listening for it more though.

 

I'm still running 91 octane and am not hearing it very often...

Am I going to have to use octane booster when my truck hits 100k miles?

100 octane Racing fuel to keep the knocking to a minimum???

 

Based only on my own testing, 100 octane pump gas eliminates the ping 100%. Thing is, it's nearly $8/gal around here and only one place sells it. Not my idea of something I'd want to spend money on.

 

All I need to do is have my buddy who is an ASE mechanic write me up something explaining my issues...

Hopefully this week I will submit my arbitration....

 

I think he is right. This worked for me. I was using any 87 octane that was cheap. I switched to Chevron super and the noise went away. Mine was ticking even at idle.

 

Could this be an issue related to the gas and not the engine it self. Since pretty much all gas now is 10% ethanol, which carries an octane (R+M/2)rating of around 100.5, when mixed in this would allow refineries to make gas that is lower than 87 octane and only hits 87 once mixed. Based on some quick calculations the gas used would be around 85.5. It's well known that ethanol had a much lower point of vaporization, thus it would be possible for the ethanol to evaporate out of the gasoline, lowering the octane rating of the fuel that actually makes it into our trucks.

Could it be possible that the above is happening, and that our trucks are tuned to advance timing up to a certain maximum point to and cannot advance any further to accommodate the "low quality' sub 87 fuel that we are running? Could also explain why this seemed to me at least to be happening in the hotter weeks of the year.

Just a thought. Anyone have a way of testing octane?

 

Today I put in 91 Octane mixed with a 1/3 tank of regular. Gas was from Chevron so I would presume it is good gas. Still getting pings. Not as bad, but still pinging. I would expect more from a modern day engine especially with all of the electronics and timing capabilities - you would think this would not happen.

 

Exactly why I want to get this taken care of now...

I have 10k miles now on my "12" and am at the point where I'm not going places because of the knocking...

If I had an extra car to drive my truck would be parked....

 

I don't think it's a volatility issue. Butane is pretty volatile, and that's something that goes in winter blend gasoline. It's pulled from summer blend because it raises the Reid vapor pressure (RVP), which contributes to evaporative emissions. Butane also has a high octane rating (I think it's 98, but I can't remember right now). If volatility was an issue, a few hours after filling up with 87 octane winter blend, we'd be staring at a tank full of 84 octane fuel.

Something that could be an issue is water. Water and gas are not miscible, but water and ethanol are. Get water in your tank full of E10 gasoline, and the water and ethanol will mix and phase separate. What's left is a layer of ethanol+water and a layer of gasoline (its non-ethanol parts). That layer of gasoline, which depended on 10% ethanol to make up the proper octane level (say 87 again) is now a tank of water+ethanol and gasoline of a lower (80-82) octane.

But water contamination in the summer would be odd. Not impossible, but odd.

As for testing octane, there are kits out there to do just that. Well, machines, really. And they are not cheap.

Also, since NY is a goddamn nanny state like Kommiefornia, I bet some Consumer Protection Bureaucracy conducts filling station octane tests (they do in California - I think it's the Department of (too Stupid to know better) Consumer Affairs. I checked the California 2012 survey report. The bureaucrats tested 87 and 91 octane fuel in a random sample of 193 filling stations. Something over 99% of them showed proper octane levels relative to pump labels. So I don't think you're seeing a widespread fuel problem.

 

I was reading about the Toyota unintended acceleration lawsuits today, and read some trial transcripts of the testimony of Michael Barr (he's an independent embedded systems software guru). The general information had little relation to our problems, but being a software guy and understanding the depth of what he was getting at, I was really surprised.

First, Toyota seems to farm out at least coding work to Denso. From what I read in his testimony and elsewhere, Denso writes Really Shitty Code. Due to Toyota being a bunch of paranoid dicks, some details were redacted in the transcript. However, it seems like the PCM OS is OSEK (in itself a decent OS). Various tasks (processes or threads, I'm not sure how it's handled) run on top of the OS, which does preemptive multitasking (think Unix-alike), but a big task referred to as "task X" handles most of the work under the hood (literally).

Task X manages throttle, spark, fuel, setting most DTCs, and by inference that means it handles AT transmission shifting, knock detection, spark advance/retard, VVT-i cam phasing, AICS and who knows what else.

Translation - BAD software design. In fact, TERRIBLE software design. It's all spaghetti code, FULL of bugs, and fixing bugs is highly likely to introduce NEW bugs. Data flow and logic flow in task X is all buggered up, it's susceptible to race conditions (think competing for access to a piece of data, to either read it or write it or both), stack and buffer overflows and according to Barr's testing, general use of task X on OSEK results in overrunning your 4k stack space (small to start with, but workable if you do proper memory management).

Oh, and task X is responsible for detecting error conditions. Except that task X is vulnerable to crashing and that crash is usually undetected. Toyota's idea of implementing watchdog timers is a joke. They basically designed the system so that 90% of the time, the dog has to kick itself. Sorry kids, it doesn't work that way. Oh, and according to testimony from Denso and Toyota, it looks like peer review of code doesn't happen. Another fail.

Mind you all this is based on his actual review of Toyota source code from the 2005 and 2008 Camry PCMs, much of which code is shared with the Tacoma and other non-hybrid Toyota cars and trucks. And if the problem is not in just the Renesas CPU (which can have its firmware tables flashed) but in the secondary CPU, we're screwed. The secondary CPU is burned at the factory and not able to be flashed. Even in failure mode (task X dead), a reboot of the CPU takes all of a few seconds (it's not like booting your PC and waiting and waiting). Except the hardware and software can't generally do that (another design failure), except in limited, almost accidental cases.

In summary, I would bet a c-note that the problem is in software and the fix is taking so long because Toyota's/Denso's code is a flippin' mess.

 

Not doubting that the code isn't pretty, but we're not talking rocket science here. In the grand scheme of things, there are not that many inputs and outputs they are dealing with, and it's not that complex of a problem. A simple read loop and set loop can execute very quickly and is simple to do. No doubt they have complicated it somewhat to make it easier to apply configurable tuning for different engines so they can use the same firmware with a different "config file" on different models. As they add more features to the engine (think later model emissions, and the 4Runner and FJ), there are more inputs and outputs that have to be accommodated for in the algorithm. Absence of some of these for the Tacoma also has to be accommodated. Limited stack space and growing complexity may not allow for fully separate code paths, so there could be some slight tuning differences between model years.

But, again, not rocket science -- they are only setting a handful of parameters each loop -- fuel, air, and spark (maybe valve, or is valve timing mechanical?) based on a relatively small set of inputs.

And, not everyone is having the same problem. Which is why I go back to one of my previous posts -- is there a common engine management component that is providing a "bad" input? It may be "in range" enough to not cause an error code, but off enough all the time to result in the knock.

 

I don't agree with your take on what the simplicity is vs. "should" be. The "task X" that Barr talks about sounds like it handles far more than you're thinking. Consider all the engine management. Add to that shift management. Lump in subroutines that will set DTCs (at least most DTCs, from what Barr observed) - one curious thing is whether or not each DTC logic tree is in a separate function within task X or farmed out to some other task. From what Barr said, it sounds like they are all in task X, which could create a timing problem (in the OS sense, not the engine sense).

Then it's probably safe to at least infer that certain VSC/stability and emissions functions are also lumped into task X. With task X taking up the bulk of the timeslices, you run into additional timing issues, or in the very least I can see this devolving into serious mutex contention and causing other tasks to spin.

I admit, this is still speculation (some of it, at least), but it's partly backed up by a professional's review of the Toyota source code with an eye towards an unrelated problem.

Here is the testimony (redacted, unfortunately) and I'm only about 60% of the way through. It has been interesting. Mind you I'm not an embedded firmware guy, so I'm used to a somewhat different world of timeslicing and CPU schedulers than he is.

https://www.dropbox.com/s/wnzqidngrtj8y2l/Bookout_v_Toyota_Barr_REDACTED.pdf

 

this is bullshit.. truck sounds like its going to explode in 4wd on the soft sand with a hard load on the motor... Might be time to trade it in...

 

Hey obscure....

That linky no worky for me.....

So are they offering you anything?

Does that mean your at the end of the road unless you want to trade it in for retail trade in value?

 

Trade it in. I did. I didnt want to wait until this pinging problem becomes so well known in these trucks that it would affect the trade in value. Traded in my2012 with 12k on it. Nissan gave me $26.5

for it in trade on a frontier. Thats like getting $28.000 after the tax savings on the new vehicle. I paid
$30k for the taco new so I feel I did ok. I had 5 years left in payments on the taco and I took a 5 year loan on the frontier. It costs me 2 dollars more a month with the 13 frontier. $27.600 for the frontier simalarly equipped. Feels like a superior powertrain but the ride is not as smooth nor as comfortable. Trade off I was willing to make.

 

I have a 2009 DCSB, manual trans with +/-57,000 on it. I use it as my everyday to and from work truck and on weekends. No other car/truck. I've always run 87 and put 20,000 - 30,000 miles/year on my truck(s) w/ my current job title. Noise started at around 50,000. It started off mainly when I'd run the AC, going up a hill and I would get lazy and not downshift. Got only slightly more frequent as it got cooler and I no longer used the AC, going up hills and hitting the accel (for passing, on the interstate, etc). It was never terrible but I've since made the switch to 93 since doing a search on TW. Although it's only been one tank, the noise immediately went away. All signs of it.

 

Well another one here. I have a 2013 Pre-runner V6 with 7500 miles. After the time of my 1st oil service at the dealer is when I notices the knocking, ticking and pinging described here. I haven't taken to the dealer yet. It mostly occurs between 1500-2000 RPM. I have tried 93 octane fuel and it did minimize the problem, but under heavy acceleration, it will still happen. 89 octane almost as bad as 87 but some improvement. At times it sounds like I'm driving a diesel.

This clearly sounds like a computer tuning issue to me, but I'm no expert. I am anxiously awaiting a response from someone on this thread regarding a Toyota fix. I'm going to take it in to the dealer next week, but I'm not hopeful. I called and asked them about it this week and all they said was it could be a number of things so bring it in and leave it for the day. This whole situation totally blows.

 

If you don't mind...

http://www.surveymonkey.com/s/L7XZ8QP