Feels Like Rev-Limiter is Kicking in at 5k-6k RPM

[csizzle84]

Hey all,

 

Been lurking a bit and unfortunately have a reason to post...

 

Just bought a '17 ABS and threw on the AkraTi, DNA Stage 2 kit and then reflashed my ECU using a PCV map via Flash Tune.  The map used was the '22-065-008 - Akrapovic exhaust DNA air filter and airbox lid'.

 

I've only had the bike out a couple of times and I've noticed that if I go wide-open throttle in 3rd gear, the bike feels like it's hitting a rev-limiter at between 5k-6k.  It will not accelerate through it.

 

I didn't get a chance to really test other scenarios (weather is preventing it now) but I can create it with that combo (3rd gear, WOT, hitting 5k-6k RPM).  It seemed like the problem only happened with WOT...I could ride trouble-free so long as I didn't hit 5k in 3rd with WOT.

 

Anyone here run into anything like that?  It feels like a break-in rev-limiter or something, i.e. no WOT past 5k or you get your hand slapped until the first service or something.  In all honesty, I've only gone WOT in 3rd...but I don't remember reading anything like that in the manual...and I'm not so sure I ever ran into the problem before the upgrades/tune.

 

Appreciate the help!

[mjh937]

That is definitely not normal.  I would suspect the ECU tune is doing something weird in that rpm range and throttle position.  I would try redownloading and reflashing the ECU to see if that helps.  Good luck. 

[csizzle84]

Hey...thanks for the reply. 

 

Yeah, I'm headed down that path.  Basically, I'm planning to flash back to stock and then try reflashing the map I'm running now.  If that doesn't resolve it, I'll go back to stock and flash another similarly spec'd map.

 

I'll post back the results here for posterity's sake...might be a few days before I can really test it out.

 

If anyone else comes across this and happens to be running the '22-065-008 - Akrapovic exhaust DNA air filter and airbox lid' map, let me know...just curious.

 

 

[digitalsteve]

I might be talking out my arse, but you wont get the ignition table from the power commander maps via FTECU; you have to manually input the table.

That might be an issue?

[csizzle84]

Nah, not at all, man...I appreciate it.  I did do that so we're covered there.

 

But as an update, I got anxious and couldn't wait until tomorrow....so I started checking things out here and I think I'm on to something...

 

I compared a lot of different ECU images to one another and the one that I uploaded had some very weird settings in the TPS vs. RPM section at WOT starting right at 5000 RPM.  I'll try and do a little write-up here later on so others can find it, but it's definitely not right.  I've reflashed and am currently reading the ECU back into a fresh file just to triple-check everything looks right.

 

More to come...

[shinyribs]

Please do report back. I'm very interested in the FT kit, but I'm no computer genius.

[r1limited]

Here is what I dont know, not mucked with flash on the FZ 'yet' what I do know is as others have stated, certaily sounds as though something is not correct in the code base effecting that RPM range.  Review it, ask them that know aka 2WD with a phone call and they may be able to put you right on the spot that needs correcting.  and BTW I am a genious

[csizzle84]

Hey guys...as promised...

 

I've uploaded 5 pics here...I'll tell the story as I progress through each one...

 

PIC:  ft-images.png - Shows the various ECU images that I downloaded/modified/uploaded, etc.

 

I started with the '2017 FZ-07 - 2RC-8591A(US) - Unrestrict.ftm' ECU image file from the Flash Tune software and modified the basic settings (disabled engine braking, lowered the fan temps, and imported the '22-065-008 - Akrapovic exhaust DNA air filter and airbox lid' fuel map from the Power Commander site).  Once I had that set, I did a 'Save As' in the software and threw a little something to the end of the file name...then it was flashed to the ECU.  All good.

 

Then, after two short rides, I noticed the problem...troubleshooting starts...

 

The Flash Tune app provides a few different ECU images out of the box for the FZ/MT-07, so I began comparing those.  It really seemed to be throttle position and RPM related (WOT @ 5k RPM) so I started looking at the TPM vs. RPM section for each cylinder throughout the different ECU images...

 

Compare these pics and check out the values right at 5k RPM and WOT (toward the far right of the graph):

 

PIC:  problem-TPSvsRPM-cyl1.png

PIC:  problem-TPSvsRPM-cyl2.png

 

PIC:  fixed-TPSvsRPM-cyl1.png

PIC:  fixed-TPSvsRPM-cyl1.png

 

The values on the 'problem' pics are WAY HIGH.  Higher than anything else I compared it to...by A LOT, i.e. breaking into the 200's.  That was clearly not right.

 

In the 'fixed' pics, you'll see a smoother mapping with values just breaking into the 100's.  That jives with a lot of the other ECU images I compared it to.

 

Side note, when I was doing the comparisons of different ECU images, I did find that some ECU images used only rounded numbers as values (86) and others used two decimal places (85.71).  That has nothing to do with this, but just an interesting finding as I was poking around...

 

In the end, I reflashed the ECU with my 'fixed' ECU image containing the same customizations as before (disabled engine braking, lowered the fan temps, and imported the '22-065-008 - Akrapovic exhaust DNA air filter and airbox lid' fuel map from the Power Commander site).

 

I then did a 'Read ECU' operation within Flash Tune to just make sure everything was programmed as expected (file name = READ-ECU-AFTER-FIXED-FLASH.ftm).  Everything looked better.

 

The real mystery is how those values were ever set that way to begin with.  I wasn't messing with anything remotely like that and the numbers don't seem to be arbitrary -- they all seem to be set with some purpose and predictability, just super weird values...

 

Anyway, I'm expecting some much smoother throttle response and power now...

 

@shinyribs - Oh, to answer your question...I think this is completely manageable for anyone with a little computer skills and some mechanical know-how.  The ECU Flash vid by Jake the Garden Snake is what I used to figure out most of the install, plus a few helpful posts on this site.  I did run into a couple of weird install problems... I accidentally pushed one of the small gray plastic dummy pins (basically placeholders for open slots on the ECU harness) inward and had to use a safety pin from the backside to get it out.  The other problem was that it didn't like the chassis ground that Jake the Garden Snake used...  I ended up using one of the fuel tank screws by the seat.  Anyway, suuuuper easy stuff -- and it was this site where I found answers from previous posts where people had already asked/answered those questions.

 

Of course it's cold and rainy today, but I'm hoping to get out tomorrow and see if this fixed the issue...I'll post a final update ASAP.

 

Hope this helps.  Hit me up if you have any q's.

Thanks!

[csizzle84]

So...not exactly a ride report here, but I brought the bike up to temp in the garage and gave a few quick WOT blips just past 5k with no issues.  I'm thinking we're good to go.

 

As I thought about it more, I'm guessing when the bike hit 5k RPM at WOT and experienced the 200+ number, the ECU probably had no idea what anything above 200 actually meant and cut fuel completely.  So cylinder 1 was probably cutting the fuel completely (> 199) while cylinder 2 still had fuel (< 199).  That would explain the rev-limiter sensation while simultaneously not having enough engine power on just cylinder 2 to accelerate out of that rev range.  I'm thinking if the engine had made it to 6k RPM, cylinder 1's TPS vs. RPM value would have dropped to under 200 (180.57) and it would have started firing again.

 

All in all, a big learning experience.  From now on, I will pay closer attention to what I'm programming...even if I have no practical experience with this, it doesn't take too long to open a few files and get familiarity with the numbers...

 

Thanks!  

[norcal616]

The generic PCV maps are ment to run off stock ECU settings due to the PCV unit not having the ability to turn on the deceleration injection to soften up the engine braking or detect that the deceleration injection is going on, so the generic PCV maps are made to soften up the engine braking feeling... also there is difference in ignition values between the unrestricted base maps and the stock OEM ignition values... the list goes on...

 

for best results in my experience using generic PCV maps is do not alter the OEM ECU settings... lowering fans temps, removing speed limiter is okay... 

[digitalsteve]

I've done a 180 on all this and I reckon I'll go down the Power Commander route instead of ECU flash... just seems cleaner.

[csizzle84]

Hey...thanks for the comment. 

 

The way I understand it, I'm not using a generic stock PCV map, but an unrestricted one that has been provided by Flash Tune for easy customization.  It is essentially stock but allows some changes that would otherwise be restricted by the manufacturer. 

 

I then import the fuel table from a tuned map file provided by Power Commander for my setup (exhaust and intake combo).  The merging of all those elements creates the .ftm file that gets written to the ECU during the flash process.

[csizzle84]

@digitalsteve  Yeah, I'm not really sure how Power Commander stacks up in comparison, but I wouldn't call Flash Tune scary or difficult.  There's a learning curve with everything.  Go with what gives you the most confidence.  

[norcal616]

the way Im reading this..

 

1. you started with the "unrestricted" map on the FT

2. you then loaded the " PCV map" on top of the " unrestricted map"  and found out it ran funny

 

3. you went back to stock map

4.loaded the PCV map on top of the stock flash and found it revs past 5k...

 

 

 

[csizzle84]

Hey...yeah, Step 1 and 2 are correct, but I ended up not reflashing back to stock after all...

 

I was going to reflash back to stock, but in my troubleshooting I found that the flash .ftm file I was running had wildly different TPS vs. RPM values than anything else I compared it to.

 

Once I rebuilt a fresh .ftm file using all my customizations and double-checking all the TPS vs. RPM values, I reflashed the ECU with that.

 

I then did a 'Read ECU' operation just to confirm all my settings matched with what I expected.  After firing up the bike in the garage and a quick test, it seems to be good.  Still need to get it on the road, but I'm pretty sure all is right in the world now...

[norcal616]

for comparison I would try the stock base map with the PCV map loaded on top and then see how it feels with the unrestricted base map with the PCV map loaded on top...

[cyow5]

My guess is that the ~200 values added twice the fuel it needed and it just rich-missed so bad it made no power. I doubt there is any logic to protect it from values that wrong, so I doubt there was an intentional cut. Doesn't really matter which though since you are right - those are grossly wrong values unless you are turbo'd. 

 

That table is basically volumetric efficiency or the percentage of air in the cylinder getting combusted relative to the size of the cylinder. Values just over 100 exist for a good motor since intake and exhaust pulsing can actually supercharge the engine a little. The values you see at WOT should also very closely mimic the shape of the torque curve, so you can see that in the 'good' map. The bad maps make it look like gets a huge torque bump whereas we know it is much flatter. Again, looks like someone actually has a turbo'd map floating around there that got uploaded, so now I want to know the story behind that, haha

[csizzle84]

@cyow5  Yeah, my guess is that they either have some protection logic in there that essentially says 'if >199.99, apply 0', or it could be more of an 'if out of range 0.01-199.99, apply null or 0'.  Who knows...  Totally anecdotal, but it did feel more like it fell flat on its face rather than being too rich to burn completely.  But who knows...maybe I had a nice pulse of flames coming out of the exhaust from the unburned fuel in cyl1 as I was bouncing off my fake rev-limiter.  :-)  The turbo map is an interesting idea because I agree...those map values are waaaaay too linear and high to be accidental.

 

@norcal616  Hey...so short of actually loading these up and running the butt dyno to figure it out, I'm going to document the differences of the various options out there so people can find it later on... 

 

I'll start with the stock ECU image from Flash Tune:

 

Here are the TPS vs. RPM values for Cylinder 1:

 

Here are the TPS vs. RPM values for Cylinder 2:

 

 

Here is the import of the Power Commander fuel table for my upgrades (M22-065-008):

 

 

They've been applied:

 

 

Here are the TPS vs. RPM values for Cylinder 1 after applying the fuel table changes:

 

 

Here are the TPS vs. RPM values for Cylinder 2 after applying the fuel table changes:

 

 

CONCLUSION:  Definitely richer in the 5000-9000 RPM range after applying the Power Commander fuel table.

 

<continue to next post>

[cyow5]

What is your TPS/MAP bias, too? Basically, you have two ways to determine the airflow in the engine - TPS or manifold air pressure (MAP) - and the ECU blends those two based on the TPS MAP bias. 

[csizzle84]

Now for my sanity, I'm going to do the same thing for the 'unrestricted' ECU file provided by Flash Tune and see if there are any differences...

 

Let's start with the unrestricted Flash Tune ECU image:

 

 

 

Here are the TPS vs. RPM values for Cylinder 1:

 

 

Here are the TPS vs. RPM values for Cylinder 2:

 

 

 

Here is the import of the Power Commander fuel table for my upgrades (M22-065-008):

 

 

They've been applied:

 

Here are the TPS vs. RPM values for Cylinder 1 after applying the fuel table changes:

 

Here are the TPS vs. RPM values for Cylinder 2 after applying the fuel table changes:

 

 

CONCLUSION:  It seems like the unrestricted ECU image in Flash Tune is actually a little richer out of the gate than the Flash Tune stock image...which is surprising to me because I thought they were essentially identical except one didn't allow certain changes to be made and the other did.  Maybe someone can clarify the difference. 

 

A bit obvious here, too, but with it being a little richer from the start, the PCV fuel table import brings the TPS vs. RPM values higher in comparison to the Stock+PCV image.

 

 

[csizzle84]

@cyow5 Hey...just learning about some of this stuff so I went to check it out a bit.

 

From the Flash Tune site (https://ftecu.com/support/kb/faq.php?id=31):

 

Why is there MAP vs RPM and TPS vs RPM fuel maps?

 

The ECU calculates fuel requirements through two methods

1. Speed Density (MAP vs RPM) Under very light load, small part throttle openings, and low RPM the ECU will use the difference in atmospheric and manifold pressure (MAP) to look-up the uncorrected fuel values.
2. Alpha-N (TPS vs RPM) Under mild to high load operating conditions the ECU will use the Throttle Position (TPS) to look-up the uncorrected fuel values.

Notes: 

• Fuel values are to be considered arbitrary. The same map value does not always produce the same amount of fuel depending on outside circumstances.
• The MAP/TPS switchover strategy varies by model but generally MAP vs RPM will be used -Usually a tuner would focus on the TPS vs RPM maps first then possibly move on to tuning the MAP vs RPM maps

So let's see what we have...

 

MAP vs. RPM mapping for Cylinder 1:

 

 

 

MAP vs.RPM mapping for Cylinder 2:

 

 

And here's the TPS MAP Bias:

 

 

 

So, I kind of put two and two together and come away with the TPS vs. RPM and MAP vs. RPM tables are blended with the TPS MAP Bias percentage value to compensate for varying atmospheric conditions under low-throttle/low-load situations.

 

That's a big guess, though...do you know how that works?  

 

 

 

[cyow5]

I'm surprised - I would've set it up the other way where MAP is used for high load. At low RPM, the MAP signal is really noisy because the intake pulses are relatively far apart. You have to use stuff like moving averages, other filters, and/or crank-synchronous sampling (where you read the pressure signal at the same point in the engine stroke, not based on a time frequency like usual). I wrote the engine controls code for pro race teams for a few years, so low RPM smoothness was a low priority, so I defer to Yamaha's expertise there, haha. 

 

From that explanation you linked, it works like this: volumetric efficiency (VE) = TPS VE * (1-blend) + MAP VE *blend. So if blend = 0.2 like in some of that table above, the actual fuelling demand is 80% of the MAP vs RPM table value plus 20% of the TPS vs RPM value. Since it is 0% at WOT, you only need to tune the TPS vs RPM table. However, tuning for a new exhaust, for instance, will need to be done in both tables at the same time. 

 

Edit: screwed that up. If blend = 0.2, the fuelling demand is 20% MAP, 80% TPS. Not the other way around. 

[csizzle84]

Ahhh, very cool...thanks for the explanation, man.

[norcal616]

A good 18 months ago or so another forum member went into detail about using FlashTune... since he had a problem with "pinging" - problem was the unrestricted base map and using premium pump gas? caused it to ping during certain times and the solution was to use the stock base map...

 

the unrestricted map is purely "theoretical" and based on no real life testing ... to me this is a map I would start with if creating some fancy style exhaust, works engine, etc and to be used with a dyno machine so I can see how the power is applied since you gotta fine tooth comb everything...

 

using the stock base map with the PCV map is how I would tune a known exhaust since its values are/where built on real life testing and PCV built its " map database" off of the stock ECU settings...

 

I had a problem with tuning my bike and came to find out PCV kept leaning out the tune since the "deceleration injection" was enabled since my ECU was flashed, had to have it flashed back to OEM to solve the problem... it kept causing the bike to stutter around 5k rpms and idle odd at each time I accepted new "trims" 

 

 

here is his tuning adventures

 

[csizzle84]

@norcal616 Man, thanks for posting that thread.  It was really good.

 

I guess it's a little different in that the newer 'unrestricted' Flash Tune ECU images seem to match the TPS MAP Bias instead of the one catfish posted.

 

But the timing is still different between the stock and unrestricted Flash Tune ECU images and that makes me slightly nervous...

 

I did get the bike out today and it ran great (no more unintentional rev-limiter), but I'm curious about running stock+PCV instead of the unrestricted+PCV like I am now.  I think your logic is really dead-on about the PCV fuel maps being developed off of the stock ECU image...

 

I did want to reach out to @hordboy to see if he had a Flash Tune ECU image available for purchase for my setup.  I'm guessing he did a lot of dyno-based tuning to create his image.