[Diy_efi] long term fuel trim

[Tim Marsteiner]

Supposedly this is the same ecu as the Triumph and
there is EH specific Tuneboy software that does allow
remapping, but it is expensive at $425. I am going to
try some cheaper options first. The first thing to do
is gather some wideband O2 data so I've ordered all
the stuff for the DIY-WB kit so I can monitor what the
ecu is doing. Most guys are saying the Super X is
running really lean from the factory. I get a lot of
pop on decel and it runs very hot compared to my
yamaha roadstar. There are reports of burned exhaust
valves...

My first plan is to replace the narrow band O2 sensor
with a wideband. I have bread boarded a comparator
circuit which will create a narrow band "toggle"
waveform from the DIY-WB voltage output. This should
keep the ecu happy. I can set the "toggle" voltage of
the comparator to any value. I believe this will
effectively allow me to fool the ecu by controlling
the long term fuel trim. For example if I wanted to
run richer I could set the comparator reference
voltage to 2.2 volts which cause my comparator to
toggle at a richer point than a real narrow band
sensor would. Somebody must have already done this
with a car. Anything to look out for?

I know the real fix is to get the tuneboy and do some
dyno tuning and tune to each point in the fuel map.
When I've learned a little more about ecus and such I
most likely will.

BTW there is no maf sensor on the super X.

Thanks,
Tim

--- Adam Wade <espresso_doppio at yahoo.com> wrote:
> --- Tim Marsteiner <tmarstei at yahoo.com> wrote:
> 
> > This is on an Excelsior Henderson Super X.
> 
> Didn't know they had used the SAGEM.  Thanks for the
> data point.
> 
> For your reference, the other makes I know of that
> use
> the SAGEMs are Triumph, Cannondale, and Aprilia.
> 
> > There is no manifold pressure sensor so I assume
> it
> > is an alpha-N only system.
> 
> If there are no pressure sensors on the intake
> system,
> it would have to be.  I am assuming it doesn't have
> a
> MAF sensor, as those are exceedingly rare on
> motorcycles.  Twins and big singles tend to work
> better with alpha-n, all other things being equal.
> 
> > I just got the bike and started learning about
> this
> > stuff. So I apologize if these are stupid
> questions.
> 
> Not at all.  There is a great deal of
> complexity/diversity in how ECUs are used by various
> manufacturers.
> 
> I can't say for sure that the long-term trim is used
> for open-loop on the E-H, but it would make a great
> deal of sense to use it that way.  I am tending to
> think that they are likely to have borrowed a lot of
> the code/strategy from Triumph, who has the longest
> history of using the SAGEM ECU (which is now
> actually
> owned by Johnson Controls, but most people still
> refer
> to it as the SAGEM line).
> 
> > I did a search on long term fuel trim and didn't
> > come up with much.
> 
> With how short a time the E-H lasted, I'm surprised
> you came up with anything at all.  :D
> 
> > By open loop I mean any time the ecu is not
> looking
> > at the O2 sensor. I would assume during closed
> loop
> > the ecu keeps track of how it modifies the
> injector
> > pulse width over time as compared to some default
> > value(factory). Then in open loop it uses this
> value
> > to tweek the pulse width??.
> 
> That is how Triumph does it (and I think Aprilia
> does
> it this was as well on some models, but I am not
> certain).  It's the sensible way to gather and use
> such data.
> 
> > it would allow the ecu to account for say a
> freeing
> > flowing exhaust and/or big air kit without a new
> > download.
> 
> It would allow it to do BETTER with those changes
> than
> a full open-loop system, but it won't eliminate the
> "need" for a change in mapping based on exhaust and
> intake changes.  If you don't change anything inside
> the engine, then it should do a pretty good job,
> within the limits of its range of adjustment.  Keep
> in
> mind too that alpha-n can have the same alpha and
> engine rpm under some pretty different conditions,
> and
> thus the "learned" trim won't be as good at
> improving
> fueling accuracy as a fresh map would.
> 
> If they are borrowing most or all of the code from
> Aprilia and/or Triumph, then there is probably a way
> to flash-remap the ECU.  I would contact Wayne
> MacDonald, who created TuneBoy for the Triumphs and
> Aprilias, to see if his software and cable can be
> adapted for the E-H. 
> http://members.optushome.com.au/wmcdonal/
> 
> > I haven't purchased the Tuneboy/TuneEdit software
> > yet because it is $450.
> 
> Ouch!  I don't see on his website where it claims to
> gain access to the E-H system.  However, for a
> single
> bike, the TuneEdit is $150 per bike, and the TuneBoy
> cable and software is $150.  Maybe you are not using
> $US?
> 
> > The tuneboy has a "O2 related fuel trim" value
> which
> > can be monitored.
> 
> Ideally, you should see almost no trim dialed in
> there.  If you are seeing bigger trim numbers, then
> chances are good you could benefit from a custom
> flash
> tune.  It may not make better power with a flash
> tune,
> but you are likely to find that throttle transitions
> are smoother, especially switching between cloed-
> and
> open-loop (like roll-on after being at cruise).  One
> very important thing to attend to before playing
> with
> the maps is that the SAGEM-based alpha-n systems
> (and
> indeed, most alpha-n systems) are very sensitive to
> TPS calibration.  If you find a similar bike to
> yours
> that has a custom tune, you can load it, but make
> sure
> your TPS is calibrated the same as the bike you got
> the tune from, or I can almost guarantee you will
> have
> problems at or near closed throttle.
> 
> =====
> | Adam Wade                       1990 Kwak Zephyr
> 550 (Daphne) |
> | "It was like an emergency ward after a great
> catastrophe; it  |
> |   didn't matter what race or class the victims
> belonged to.   |
> |  They were all given the same miracle drug, which
> was coffee. |
> |   The catastrophe in this case, of course, was
> that the sun   |
> |     had come up again."                    -Kurt
> Vonnegut     |
> 
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