Tacoma - OVTUNE - VFTUNER - Update Info and Original Development

Very well said. Thank you.

I’m expecting to be running OBD Fusion on a Kiwi3 by today because I want to be able to articulate my desired tune characteristics. It makes it difficult when things are done a certain way (that may be perceived as undesirable) because alternative configurations will produce... “undesirable” consequences :/

Example: The shifting in the 1-4 range, I believe is set up to:
A) conserve fuel and
B) reduce/eliminate the “down shift clunk”.
Well for some reason, my truck has worse fuel economy and the clunk is back (had been absent since 103)

Now I’m left wondering what to ask for (with regard to a custom tune) and more importantly, at what expense

This isn’t a ticket worthy concern/issue/preference. Just me thinking out loud about custom tuning. I can’t imagine how difficult for Mat it’s gonna be to custom tune each individual request, so I’m trying to do the best I can to be as prepared as possible when custom tuning is available.

I know (he must have his reasons) that May doesn’t want to make any more mass tunes, but it seems like there are large enough groups that are saying similar things to be able to address their issues/concerns/preferences with a couple “large scale custom tunes”.

I would certainly not expect this to happen until after the MT crew gets dialed in.

 

You can't fix hardware issues with software. I say this all the time at work. No matter how much code I put into a PLC, I can't fix the fact that a hydraulic check valve has blowby, the motor selected doesn't have enough torque for the application, or the cam follower on your machine is sticky. Any code I write is a bandaid.

Our trucks have some significant design flaws from Toyota. The best you can hope for is to mask them, and that can produce other un-desirable side effects. I think that is what a lot of people are experiencing. Software to fix a "clunk" in the drive train can also give you odd shifting behavior. There's no way around that. Everyone needs to understand that 1.05 base is supposed to be a happy medium that 90% (of stock) customers will be happy with. For everyone else there is custom tuning.

 

Half if not more of the clunking is relayted to DFCO.
Half if not more of the surging is relayted to the REVHANG .
More can always be done if the will is there.

 

I agree DEFCO is still an issue, but it isn't the source of the "clunk". I believe the root cause of that is driveline slack.

You keep insisting that there is Rev-hang and I just don't see it. Maybe it's a problem for some. IDK. Logging and custom tuning should be able to fix that. However, again, I don't see how this creates surging.

Again, MECHANICAL problems can't (shouldn't) be solved by software.

 

I gotta be honest, I think I fell in to this trap to a certain extent. B04 individuals said they had idle flux in certain areas so I looked for it. Creating a placebo of sorts in my mind. If they have it, I must have it. So I emailed asking for said "fix". After running the fix for a week, I swapped back to the original. Which was perfectly fine to begin with.
I fell in to the trap. I admit it
Anywho. I have one thing I'd like different and it's not an issue. It's user preference. And I'll ask for it when/if custom tuning becomes available.
Thanks for everything Mat.

 

A large source of driveline clunk is low transmission fluid and people’s refusal to verify it is filled to spec.

Followed by that is driveline slack.

 

If you don't have the problem then you have to guess, but some user with the clunk ought to be able to verify too much slack. But......some customers have reported clunk appearing/disappearing with different versions of the tune (including Toyota tunes).

 

i am not blaming the lash. what i am asking for is to eliminate the DFCO and REVHANG for a true throttle by cable feel.

the REVHANG for MT and AT
this an exert from the link below
Cars fitted with automatic transmissions suffer the same rev hang problem as cars with manual gearboxes but drivers are much less aware of it because of the design and function of the auto 'boxes, especially those fitted with torque converters.
http://www.revhang.altervista.org/

the DFCO for MT and AT
this is an exert from link below
Clunk normally occurs during the torque reversal generated by application of the throttle following a deceleration fuel cut-off or a high engine vacuum fuel deceleration
https://patents.google.com/patent/US7881846B2/en

 

Mat has reported that he does not have stock tires. So there is that. I do understand that many have larger tires and to varying degrees weight/armor. But there currently is no way of knowing how many, although Mat has claimed "most of our customers do". As do I.

The common response Mat gives is that everyone experiences something different, and all these Tacomo's are different. We will all get better tunes if we at least to endeavor to find out why. IMO, the base should be stock.

Mat has done and is doing great work. What is wrong with advocating for "better"?

 

I understand perfectly what you are talking about and i'm not arguing with you.

Rev-hang on MY truck and in MY experience is minimal and not much of an issue. YMMV. (not a hardware issue, so fixable by software).

DEFCO (is a software issue).

Clunk, - In the link you posted it talks about software mitigation for a mechanical issue. You can't beat physics. The software fix for easing torque reversal issues can absolutely affect how the transmission shifts/TC lockup. The clunk is still a mechanical issue. It is not specifically tied to DEFCO. It may be possible that the ECU has a super-special area that is separate from shift logic to handle this like the patent you linked. IDK, and maybe Matt hasn't looked into it yet.

Mechanical issues ≠ software issues. That was my only point.

 

105 91 at worked great from sea level to 6500 feet. Great throttle response in 4h S2 4000 rpm in the silty clay I drove though at 5500 feet.

 

My experience with 1.05.
Dcsb 4x2 TRD sport
285/55/20 3in lift
PREV on 1.04 91oct

Started with 1.05 93. Initial impressions were all great. No gear hunting, no chugging without power, nice coasting feature, mpg exactly the same 17mpg as 1.04. Definitley felt the difference in acceleration being less than 1.04 but not bad, really smooth. After 600 miles everything was about the same but mpg had gone down some to 16mpg.

Wanted to try 91oct to compare mpg. Only have 200 miles on so far, but feel like this version is settling very nicely. Averaging 19 plus mpg and still all the other pluses from before. If it stays like this, I don't know that I'd gain much from custom tuning. Thanks Mat.

 

After you run 91, try 87. You may be surprised...

 

Low transmission fluid maybe the cause of clunk for some, but wasn't in my case.

1.03 I had 2>1 clunk coming to stop. Warm and cold.
1.04 no clunk, 1.05 (all revisions) no clunk.
Same truck, same amount of transmission fluid in the pan, which is full.

So for me, the clunk was definitely caused by 1.03, because NOTHING ELSE changed.

On positive note, I'm enjoying 1.05 91. My truck have never run better. I do exhibit slight cold idle fluctuation, it is fairly minor, ccurs after cold start, when engine is warming up and rev is coming down, or if I start the truck with a warm engine and put it in D right away. I'm hesistant to email Mat for the fix since some user complaint it changed their tip in. I think the tip in is spot on right now. Will wait for custom tune and work with Mat to sort out these minor "issues" / "observations" / "none gender binary incidents", or whatever you sensitive hippies want to call it.

 

So since we have had 1.05 out for a while. I’ve tried all the octanes. All significantly make the truck better.

Anybody have suggestions for the magic combo of tune and octane? I had the 87 tune but running 91 in it for a short time and I remembered it being pretty awesome, I’m on the 93 tune now, it’s great too but been thinking about trying the 87 tune with 91 again can’t remember if the shift points were maybe smoother than the 93 tune. Just don’t know if I want to keep spending the extra money on fill ups for 93 either.

So yeah friendly discussion. Anybody feel like 87 tune with 89 or 91 octane in it is better or just as good as the 93 tune? Worth continuing to pay the extra for 93? What about best combo for MPGS?

Oh and Mat, all I can say is thank you. I ended up removing a bunch of crap on truck (cough Prinsu cough) and man the truck came to life with 1.05.

 

Has anyone ever seen 93 octane quality, or lack thereof, cause a dramatic swing in fuel efficiency before?

I've been running 1.05-93 for about 450 miles. My last tank with Shell's 93 octane -- also the first full tank with the tune -- resulted in an overall average of 16.9 mpg for the tank (city driving). However, with my current tank of 93 octane fuel from Sam's Club, I've been driving like a grandmother around the city and still can't get the damn truck to reach any higher than 13 mpg.

More testing is obviously needed, but things are getting a little strange. I guess I'll refill with Shell 93 later this week and see what happens after that. Is anyone else seeing similar results with the tune and/or 93 octane fuel itself? I'm just trying to troubleshoot this effectively...

 

I think fuel octane scams are a lot more common that people think...

https://www.lisamadigan.org/in-the-news/2018/3/12/rockford-gas-station-sued-for-high-octane-scam

https://www.nj.com/news/index.ssf/2018/07/22_nj_gas_stations_cited_for_violations_after_surp.html

If you're getting an extra 60 cents a gallon on say 10K gallons a month you've made an extra $6,000.

 

I think it would be one hell of a scandal if a company like Sam's Club tried that, but I guess I can't rule it out.

If switching back to Shell gasoline for my next tank doesn't solve this mystery, my next test after that will be to re-flash the 1.05-93 in hopes of eliminating the ECU's "learning" function as the cause for the drop. I'll start over.

Maybe I'm babying the engine too much by driving it like a grandmother, and doing so somehow screwed up its brain?

 

I would look to their distributor/driver if there was an issue. I doubt Sam's would do something like this intentionally.

Edit - Could also be water according to this...

Edit 2 - Pro tip: Fill up from the pump closest to the tank. Eliminates at least some of the path where water could get into the fuel.

 

It’s gonna be that tank of fuel. Burn half of it and fill up. Or burn it all then fill up. No need to reflash. It’ll climb back up after you’ve replaced that fuel. It’s not unusual to get a 2-5 mpg swing in fuel economy from what I’ve seen with my truck but it always comes back up.