Tacoma - OVTUNE - VFTUNER - Update Info and Original Development

Well, I'm happy to say that my truck on 2.0 beta runs very, very smooth. I appreciate the input to alleviate my fears.

 

That's the issue with the tune. In my case, I get 15 + in 1st 3-5 min of driving, even when intake and ambien temps at or above 70°
20+ is daily normal on 20 mile commute on current beta. A few time I got 32, no cel

I've been monitoring TSB stock since end of last summer and never seen double digits in 1st 3-5 min driving. The most I've seen was 12 on 20 mile trip,
It is not a quality of the gas, hardware. there is something missing in the logic to deal with ignition. Idk, bit TS has misfire probability parameter and it is pretty accurate to prognose incoming misfire
ECU must have some equation to calculate it, therefore we could potentially figure the input parameters out.
For me, misfires are the priority, I can recognize them by now and they do shake the truck. I wish they were "calculated"

..

 

Misfires was a topic talked about to great lengths on here by Mat and a few others I wanna say around the 1.03 timeframe? He said that Toyota has a fudge factor for engine misfires that will say misfire but it actually didn’t misfire, it just fired a fraction of a nanosecond to early or late he said you needed a stupid number of recorded “misfires” for it to be considered an issue and to trigger a CEL. Something like 100something misfires In so many rotations of the engine. Don’t quote me on any of that but that was the general gist of things. A quick search should yield his post though.

 

...that is it. We are asking to put the fudge factor back..

 

Sorry guys if this has been asked already, there is just too many posts to go through. Will cable included with OVI kit work to run a TSB update for manual from another thread?

Just want to get one package, run TSB first and then OVI on top of that. I will be investigating the matter over the weekend, but looks like there is tons of info to read.

 

yes, absolutely.

 

Bumpy roads/offroading can also trigger a "misfire". Last time offroading on a particularly vibrating road, they were popping up (on OBD Fusion) like crazy. Like Mat said before, it's just measuring parameters of where the firing "should" take place, not necessarily saying a true misfire has occurred.

 

really like the 1.05.1 , 91 base tune, just wish I could control the gears with the shifter

 

You mean, having a manual transmission?

 

a "real" manual with a cable and not a wire...like my TJ

 

The ECU tracks a value called "Misfire Margin" which is a measure of the range of variablilty in engine speed that is acceptable before the ECU triggers the misfire counter. So basically if the engine changes speed beyond the threshold, it is determined to be misfiring so it wouldn't surprise me if the engine flagged a misfire sometimes as a false positive. A CEL is not triggered on our trucks until there have been >35 misfires in a 1000 revolution cycle. So if you're in 6th at around 1100 rpms, it would need to misfire 35 times in a minute or so before it would flag a misfire. Per the field service manual 0-35 misfires in a 1000 revolution cycle is "normal condition" - so think about that. 35 in a minute is a lot IMHO. you'd feel the loss of power, but the truck wouldn't tell you anything was wrong..

 

But is it needed? I'm not a programmer or engine tuning specialist by anyone's standard but I have been involved with racing and engine building for the last 30 years so I have beyond basic understanding of engine operations. To me the misfire count isn't a concern. If I was getting actual misfires then it'd be a major concern but the fact that it isn't actually misfiring AND the fact that the tune is keeping the misfire count consistent to misfire counts on the stock tune (which isn't a concern to Toyota) makes it a non-issue to me. The only issue that I see with the misfire count is that it causes people that have no idea about using these logging tools to start flipping out about the misfire count when they see it show up on their OV tune. They don't realize the misfires were there when they drove it off the lot and Toyota has no issue with it but now they are aware that it's there and they start tracking it compulsively thinking they have issues with the tune. To me, at this point (and I accept that I could be wrong) it's just a value of 0 that people are chasing after but it will gain us nothing in the real world when its attained. If the fudge factor is put in and a delay of say 1.5ms would no longer trigger a misfire count then would we get a CEL warning if an actual ignition problem were to arise? I assume that a blatant misfire would have a value far greater. 30 misfires for 1,000 revolutions (about 30 misfires in 25 seconds at 3,000RPM) is WAY different than 15-30 misfires over a 20 minute drive.
I'm not saying chasing after the elusive 0 misfire count is right or wrong, I just don't feel it should be a major concern at this point to get caught up on. I view it as a variable that falls within acceptable parameters.
that's just me though

 

Touch the two battery cables together once disconnected from the battery - DO NOT connect the positive terminal to the negative terminal.
I'm sure you already know that is a bad thing unless you like sparks and want to replace the battery.

 

There are at least some trucks that have higher misfires tuned than they do stock. I can see your point about not being overly concerned with these elevated counts (I’m still running the tune).

I think it is prudent though to make the goal equal to or less than stock... not necessarily 0

 

Totally agree it should be a goal, just not something that needs to be main focus or sought out by members that don't know how to use logging software or understand what misfire counts are on a bigger scale. People who understand the count should definitely track it but it should be made known to new people that 20-30 misfires in a 20 min drive is not a crisis and most definitely not the same as 35+ misfires in 20 seconds of normal driving (enough to trigger a CEL). Information is good for people that understand it and relay it back to Mat but in the hands of Lawyer Tim who bought his Tacoma to go "overlanding" so he can let his beard air out in the backcountry on the weekend before his big corporate meeting on Monday, telling him to get Fusion to track his misfire count will only cause problems down the road with unsubstantiated complaints on the forums and no productive feedback to Mat. We've been down that road too many times

 

Trust me, we do want to believe in " no harmful misfires", but it is hard for us to differentiate good vs bad misfire on the monitor.
Especially after comparing OEM calibration to OV for the same environmental parameters.

I experienced dead cylinder registered under the same count on many occasions since release of 1.05 in TS and Fusion apps.

Well ,here is another one for folks who pay attention to detailes.
TC temp went up by ~10° F on 2.0 versions.
Is it good? Is it bad? Or I need to go check the level..?
I know that TC locking algorithms were change, but...

 

Can you clarify what you mean by "dead cylinder" ?

Also from what I recall your reports, and most others are they see these misfires under the very first / cold engine driving. When the engine is not up to temp there is a table that multiplies ignition for cold coolant I still believe this is the culprit for the few trucks that have seen higher misfire counts on cold engines.

Overall this issue is a very small amount of people vs the total amount of trucks we have tuned. I've said countless times that there is not going to be a file that we release to the masses that will fix it for trucks that have this, and the trucks that do require a custom touch. It is great to test current files and do some comparisons but lets not forget that these trucks are going to need a bit of additional tuning.

The issue is so variable that it's hard to make any *exact* determination.
Some trucks have higher counts tuned than stock.
Some trucks have higher counts stock than tuned.
Some trucks have bad crank position sensors, replaced them, still occured.
Some trucks have good crank position sensors, still occurs.


When a misfire becomes harmful requires more than just a total count over a drive cycle. It requires multiple, consecutive, in a very short amount of time. Not one here, one there, one 5 minutes later. Every single car has misfire counts sometimes.

Finally, "misfire" in OBDII isn't "misfire" like some people think it is. It isn't the cylinder "Not firing" it's a difference in time calculation for the crank shafts movement.

 

On a different note from “MissFires” just received the handheld ... just waiting on the formal instructions on how to go about using it