Lowest Load value doesn't seem low enough

[ReadyXB]

The 1125 is factory equipped with a MAP and baro sensor. The MAP sensor attaches via a vacuum tube to the throttle body. Part# P0508.1AM.

 

[ReadyXB]

I checked BUEOD (feature not even available), BUEYD, BUEZD, BUE1D (XB9), and BUE2D EEPROMs and the feature "TPS and MAP Load Setup: Enable TPS/MAP load feature" is disabled, and the "MAP to Load Table MAP Axis" tables are empty.

All of this was done on XB EEPROM data. Does anyone have a stock 1125 EEPROM (any year) they can post for me to check?

 

[Negative]

Ha ! ... very nice work ReadyXB !! ... Guess my assumptions were close enough for government work at least ... lolol [up]

Good **** !!

 

[ReadyXB]

I am slowly working on a DDFI-3 setup for my XB that will utilize the MAP sensor and TPS to determine load. It is quite a project, though.

I want to do the same thing! I think you're right, though; it will be a challenge.
I also plan to put 2010 XB12R headers on my 2008 and add the second O2 sensor, but that will come later.

 

[EricZ]

I'd like to think you're right, ReadyXB, but I have yet to see a 1125 eeprom that uses the MAP sensor signal for anything more than injector timing. I meant that they don't use them to determine load....fueling or ignition timing.

 

[ReadyXB]

No, I agree! I DON'T think anything except TPS is used for Load. I think all other adjustments are made -after- the Load/RPM lookup. That's what my investigation and reading has found so far.

...Which is why I can't figure out what ich meant when he said I was wrong about TPS alone being used for Load. He said "Not true for DDFI-3". That statement is what sent me on this side-path trying to confirm what he said.

ich! Help! This is killing me. What did you mean?? My brain needs peace!

 

[ReadyXB]

So I have an update in case anyone was following this thread.

It took more time and investigation, but I have found two ways to artificially affect my Load value - at least the base/reference value.

1. "Throttle Position Sensor Reset Voltage"
This correlation should be no surprise
This is the value that gets updated when you do the automagic 3-step throttle twist on DDFI-3.
I modified the EEPROM value directly to not only confirm but to also see the trend.
- increasing TPS reset voltage values causes LOWER base load value
- decreasing TPS reset voltage value causes HIGHER base load value.

FYI: I had to temporarily disable the "Enable TPS auto zero feature" flag. Fortunately it didn't take long to figure out I needed to do that. I had been twisting the throttle so much during this investigation that I on many occasions saw the Load mysteriously change. After brief frustration, I realized what was happening and cleared the flag.
Sanity check confirmed.

2. "Idle Air Control Throttle Position Adjustment" table
This one was surprising at first but it does make sense, and it was worth the effort of experimentation because I learned something!
As with TPS reset voltage value, modifying this table will artificially change the base Load value.
My default is:

Steps | TPS 8-bit (not 10)
--------------------------
10 1
20 2
30 3
40 5
60 7
90 11
140 17
200 17

- Increasing the values in the TPS 8-bit column resulted in HIGHER base Load value.

Having said that, it's important to note that all I've done is alter an initial "calibrated" reference Load value. I haven't made any meaningful change to the run-time Load value calculation since the TPS-IAC table is static.

--------------------

So if I am deducing accurately, both TPS and IAC do affect the Load (on DDFI-3). In hindsight this makes sense because throttle position and IAC position both affect RPM. Higher RPM, whether due to Throttle Position or IAC position, affect the amount of air entering the engine. More air means a corresponding increase in fuel is needed, and this is accomplished by changing the Load value. And, DDFI-2 has no IAC, so only TPS affects Load in that case.

ich, is this correct?

 

[ich]

weitgehend ja.

 

[ReadyXB]

weitgehend ja.

Thanks, ich. If google translated properly, you said I am "mostly" correct. Mostly correct is not fully correct, and my personality won't let that go. So what else am I missing?

ECMSpy Q&A, Q18 says

The TPS-8bit value, which represents the Y-axis in all DDFI and DDFI-2 maps, has been renamed to 'Load' (rear cylinder) and 'Load1' (front cylinder, where applicable). DDFI-3 won't use the TPS input on it's own for calculating load, but is capable to add MAP sensor input to this calculation also.

Capable - ok. But after looking at a stock 1125 BUE2D eeprom (thanks to a helpful forum member), the flag "Enable TPS/MAP load feature" is Off, and the Front/Read MAP to Load Tables are empty.
Capable - yes. Enabled - no. Unless there is some other way of enabling MAP to factor into Load besides that flag?
Without an 1125 of my own (would be nice), there's a limit to what I can tinker with.

I am eager to learn and have done due diligence. There is a lot of misinformation around, on this forum and on others. I don't want to perpetuate misinformation or mislead anyone. Misinformation can and has cost people money.

If you are unsure about the inner workings of Load, that is fine! But if you have more knowledge, I would appreciate anything else you can share to help guide me. Thanks for your help so far.

 

[Negative]

Woo man ... There are soooooo many more changes to DDFI 3 than I thought ...

 

[ReadyXB]

So I have been helping a gentleman who has quite a nasty issue on his 2009 XB12Ss with stock ECM.
My head has been buried for many days scouring through 17 datalogs.

But the reason I am posting an update in this thread is because those datalogs were from a BUE2D ECM. The interesting thing to note is that the lowest Load value I observed in his logs was 14 - close enough to mine . And, loading up his ECM configuration showed that the Fuel Map Load Axis in this BUE2D starts at 00: "00, 06, 10, 15, 20, 25, 30...", which is also the same as my BUEOD and recently acquired BUE1D.

Now, if you scroll back or remember what I posted earlier, the stock BUE2D data that I referenced (which was posted by user SEXT9 ) had a Fuel Map Load Axis starting at 06, not 00.

So we have two XB12 BUE2D ECMs with different stock parameters! The reason for the difference, I believe, is that the BUE2D I am helping troubleshoot is from a 2009 XB12, and the BUE2D from SEXT9 is from a 2010 XB12. So, if I can trust that the EEPROM images provided by these two users are in fact stock, then it would seem that Buell changed the Fuel Map Load Axis for the 2010 models, along with a handful of other parameters.

You are probably now saying "what about the higher starting eeprom fuel map load axis values you mentioned in your first post?"
You mean these?
BUEZD: 10, 15, 18, 20, ...
BUE1D: 10, 15, 18, 20, ...

Well I asked myself the same question today. Retracing my steps, those came from (supposedly) stock EEPROM images which I found at another Buell forum. And only after reviewing all of this information again did I notice the following about those BUEZD/BUE1D images. Check out the full Fuel Map Load Axis inside of them:

255
255
175
125
100
80
60
50
40
35
30
25
20
18
15
10

Notice anything strange? I double checked with a hex editor in case the XDF was wrong, but it's not. I'm not sure how/why 255 got in there twice, but I don't think that was ever stock because it just doesn't jive. If anybody has data to confirm or disprove, please let me know! But I will say it won't be the first time I have found bogus "stock" eeprom data posted online. So that's problem #1.
The second problem is that they begin at a load of "10". These values were in a DDFI-3 ECM?. Yet the only time I see a load axis starting at value "10" is in DDFI-1/2 ECMs, which use only 12 bytes for the load axis, not 16 bytes as with DDFI-3. So not only is Load 255 in there twice, they start at Load 10 which seems to belong in DDFI1/2 ECMs. Hmmm...

 

[ReadyXB]

To summarize, and to the best of my knowledge, the Fuel Maps Load Axis values for 2008-2009 DDFI-3 ECMs start with load 00, and the 2010 ECMs starts at load 06. And I haven't found any evidence that makes BUEOD any worse than BUE2D in regards to the lowest Load value observed. Yet.

 

[s0dhi]

Well, I just checked mine BUEZD ecm and it has two 255 load entries on the map and starts at 10 in stock form.

 

[ReadyXB]

This is so strange. Does that make sense? Two fuel map rows end up being duplicates:

 

[s0dhi]

ReadyXB,

Yup. It's crazy. Exactly the same on my factory setup. Not sure why it's set up like that. I always wondered if that axis could be redefined to remove that extra 255 entry and put in another one some where lower where additional resolution would be needed.

 

[John422]

So I haven't read this whole post but I will say when we dynoed a cr that was built up and had a power commandor 5 we ran into the probablem of the rear wheel hopping on drum when putting the load on the motor. That day we could only tune from 4 grand to 11 and he has an s tail on if too so he went home and got his passenger pegs and we threw those on and strapped it down hard so then we were able to finish the tune from there. So that's probably what your seeing. When they made the maps. They probably ran into the same problem of that rear wheel not staying planted.

 

[ReadyXB]

Hi John, I think this case may be a little different. I am trying to understand why certain seemingly stock ECMs have duplicate "255" Load entries in the ECM's Fuel Map Load Axis table, and also duplicate Load=255/RPM rows in the fuel maps. The topic has strayed ever so slightly from my original post, so I may just create a new thread.

 

[Rob41473]

So I have an update in case anyone was following this thread.

It took more time and investigation, but I have found two ways to artificially affect my Load value - at least the base/reference value.

1. "Throttle Position Sensor Reset Voltage"
This correlation should be no surprise
This is the value that gets updated when you do the automagic 3-step throttle twist on DDFI-3.
I modified the EEPROM value directly to not only confirm but to also see the trend.
- increasing TPS reset voltage values causes LOWER base load value
- decreasing TPS reset voltage value causes HIGHER base load value.

FYI: I had to temporarily disable the "Enable TPS auto zero feature" flag. Fortunately it didn't take long to figure out I needed to do that. I had been twisting the throttle so much during this investigation that I on many occasions saw the Load mysteriously change. After brief frustration, I realized what was happening and cleared the flag.
Sanity check confirmed.

2. "Idle Air Control Throttle Position Adjustment" table
This one was surprising at first but it does make sense, and it was worth the effort of experimentation because I learned something!
As with TPS reset voltage value, modifying this table will artificially change the base Load value.
My default is:

Steps | TPS 8-bit (not 10)
--------------------------
10 1
20 2
30 3
40 5
60 7
90 11
140 17
200 17

- Increasing the values in the TPS 8-bit column resulted in HIGHER base Load value.

Having said that, it's important to note that all I've done is alter an initial "calibrated" reference Load value. I haven't made any meaningful change to the run-time Load value calculation since the TPS-IAC table is static.

--------------------

So if I am deducing accurately, both TPS and IAC do affect the Load (on DDFI-3). In hindsight this makes sense because throttle position and IAC position both affect RPM. Higher RPM, whether due to Throttle Position or IAC position, affect the amount of air entering the engine. More air means a corresponding increase in fuel is needed, and this is accomplished by changing the Load value. And, DDFI-2 has no IAC, so only TPS affects Load in that case.

ich, is this correct?

I am trying to help a friend of mine tune his bike (neither of us know that much about it). He purchased an XB12s 2008, DDFI 3, BUEZD, K&N filter and a Jardine pipe that has been gutted completely (just an empty can). I am trying to use Tunerpro RT to tune this bike. I finally got it to connect read/write and log. (1) I then noticed the bike never got below the 20 load (23 when bike was not running). TPS reset does not change it. I found this thread and tried to follow the instructions you had posted. I changed the "Throttle Position Reset Voltage" as much as I could but could only get the TPS 8bit to get down to 11. I couldn't figure out exactly what to do with the "Ide Air Control Throttle Position Adjustment" (my table matched your default table). (2) I have read the Tunerpro RT tuning guide by Jared Zuech as well as Mike Cobbs. I read that the history table shows you a percentage that ECM is using to adjust the MAP, I read somewhere else that you should copy the history table to your MAP. Not sure which is the correct way. Any help would be appreciated.

 

[s0dhi]

ReadyXB,

Yup. It's crazy. Exactly the same on my factory setup. Not sure why it's set up like that. I always wondered if that axis could be redefined to remove that extra 255 entry and put in another one some where lower where additional resolution would be needed.

So, after a couple of years I've finally got a chance to fiddle with the ECM again, now that I have a new exhaust. I got to thinking about the Load and RPM axis setup again. I removed the duplicated 255 load point and added load point 6. While I was at it I decided to make use of the 4 unused RPM columns as well, stretching the axis and resetting the RPM points, hoping to get better granularity and the prospect of smoother transitions.

Initial runs are promising and bike is running quite well.

 

[s0dhi]

So, after a couple of years I've finally got a chance to fiddle with the ECM again, now that I have a new exhaust. I got to thinking about the Load and RPM axis setup again. I removed the duplicated 255 load point and added load point 6. While I was at it I decided to make use of the 4 unused RPM columns as well, stretching the axis and resetting the RPM points, hoping to get better granularity and the prospect of smoother transitions.

Initial runs are promising and bike is running quite well.

I think adding the load point of 6 was a waste based on reviewing the scatter plots. I think that row is better suited to 45 or 70 where the value is actually getting hit and can provide more detail in the curve.