TampaSVT wrote:
ahamay:

Hmmmm... Pretty trusting of you...

Well, if you trust the fact that they've already tested and are advising you not to waste your time to verify those results, then I don't have much more to say on the matter...

RichWell it saved me a trip to the Dyno and $135.00 for dyno time. This was an engineer I was talking to not a phone technical support type. After looking at all of the fuel curves and pipe/aircleaner combinations I would have to say it was not blind trust. The unit I have is for the California market and it is C.A.R.B. legal. You know the C.A.R.B. people checked it to be sure that the unit met air polution requirements. Dynojet has a good reputation in the industry and I really haven't heard a bad word about them except here on this board.

texasscott1 wrote:
River wrote:
I think I understand what you are saying Scott, But you are not being simple enough for this dummy.

What sensors decide this? If the after market fuel controllers are able to change the status, then isn't it fooling the computer into thinking the o2's are sensing something else?

What sensors beside the o2's feed the computer for fuel adjustment? If an after market fuel controller can cause the computer to add more fuel, then the computer is capable of adding more fuel.

If it is getting this info from the o2's alone, then isn't it reasonable to think that if you back out the o2's from the exhaust stream a tad or put a variable resister in the o2 line, couldn't you do the same thing?

I don't want to cause confusion or you to think I doubt your word, I am just trying to understand where the computer gets its information from.
Thanks.

1st question, yes. On a Star bike with an AIS the computer may be expecting to see an O2 voltage averaging say around 0.2 during idle and light cruise which is very lean but okay because of the air coming from the AIS. If the fuel controller is made to work without the AIS then it will adjust fuel flow so the O2 reads around 0.45 volt which is a 14.7:1 AFR and send a different voltage reading (the one it's expecting) to the stock computer.

The other sensors are the MAP (manifold absolute pressure) sensor, engine temperature, atmospheric pressure, air temperature, engine speed and the TPS. The input from the temperature sensors is obvious - the computer needs to know the intake air temperature and the engine temperature.

The computer FI system sensors convert atmospheric pressure and manifold pressure to a voltage signal. Everything is measured in absolute pressure which at sea level averages 29.92 inches of mercury. In the simplest terms the computer compares the difference between the surrounding air pressure and the pressure in the manifold and makes a determination about engine load. The TPS plays a part also but let's take an example of cruising on the highway with the throttle lock set. Without the MAP sensor on the FI system the computer wouldn't be able to sense more load when the bike starts climbing a hill (same throttle setting, more load and the pressure difference increases). The equivalent on the CV carbureted bikes is the slide diaphram.

A resistor in the O2 circuits. That can be done and has been done with the VStar 950's and 1300's because they run lousy with aftermarket filters and pipes. Why anyone would want to change those bikes is beyond me. The stock exhaust on the 950 is pretty mean sounding already and the 1300 will already outrun the Roadie and maybe the 950 as well.

What you would have to do is measure the O2 sensor output with the AIS connected. The sensor is sending voltage readings at the rate of about 8 times/second and they're always above or below the desired reading. If the reading is very low then there won't be enough room to lower it with a resistor. The idea is to provide a resistor that lowers the voltage enough so that when the computer gets it it richens the mixture enough so that the voltage from the O2 sensor before the resistor is around 0.45 volt (14.7:1 AFR). This may be exactly what some of the aftermarket fuel controllers do, I don't know.

As far as acceleration mode goes the O2 sensor is ignored anyway but with the volumetric efficiency increased the stock computer may be approaching the limits of its map.

I'm going to stop here. Let me know if I was vague in some area.

Ok Scott thanks, I think I understand just a little bit how this works and I think I understand why the bike quits 'after firing' when we remove the AIS.

When we try to have a conversation about how these systems work it always degrades into "Why put after markets controllers on?" And that isn't my goal to answer that, but simply get a better understanding of whats going on in the brains of the bike.

Do these bikes run TOO LEAN after removing the AIS? Good question.I would just guess that the aftermarket controllers fool with the voltage on the o2's so that the computer no longer see's a false signal by driving the voltage on the o2's to a more favorable range.

Whether it needs it or not? I'm not really sure, but from the looks of the plugs, they look pretty good, but I haven't done a clean cut yet.

My feeling though is that we (or at least me) are not tuning the bike for racing.
However with the baffles the way I have them now the bike runs like a striped assed ape and I do like a little performance.
Without tuning the mufflers to the engine it was a dog.

People had basically these same problems when they started running HHO in fuel injected engines. The HHO would drive the voltage high in the o2's and cause it too lean out the mixture on the injectors.

We have a lot of winter rain in Western Washington so I have a lot of time on my hands. That gives me time to learn more about these bikes and their fuel systems, but I think you are right about these computers being 80's technology and I think that is in our favor.

Sorry to degrade the conversation. Won't happen again. You guys seem to be the experts.

But, I'm still asking the same question. Why?


Rich

TampaSVT wrote:
Sorry to degrade the conversation. Won't happen again. You guys seem to be the experts.

But, I'm still asking the same question. Why?


Rich

Rich
I'm with you on this one. All that theory on how it works is fine and well. But what works? It seems that leaving things alone works just fine or should I say better (in most cases) than with a controller. I would still like to see Dyno's on a stock setup and a modified setup without controller. Seems that most that fall for the "you need a controller" end up removing it and get better results. Like I said on the other post, When I had a few Dyno's done on my bike the dealer always said I was running lean @ a AFR of 14 at cruise speed/RPM. They wanted it at 13.8 or lower. That is rediculous. I have a AFR gauge on my bike and run at about 14.5-15 at cruise. And everything is fine. And for you guys that are gonna say I must have a air leak for it to vary that much tell ya up front your wrong. My gauge tells AFR in real time and a good gust of wind into the Bak will change the AFR. It is constantly changing in the 10ths on the gauge. When you get a reading from a Dyno it gives a smooth even line on the sheet more as a average or buffered reading. Just like your gas gauge is buffered so that its not bouncing around when you turn a corner. On a carbed bike the dealer will rejet when they install just pipes. Again Dyno results is the only thing that will convince me on the controller. Glad I have a carbed bike.

River, with a full throttle cut the mixture might be okay because remember, in that situation the computer switches to "open loop" operation shuts off the AIS and ignores the O2 sensors. With a sniffer up the tailpipe you can try a full throttle rev from idle and see if the machine will catch a snapshot of the full throttle AFR. You'll be looking for something in the 12+ range. I've read that about 12.8 is good. Anyway, the voltage you would be looking for from the O2's at full throttle is between 0.8 and 0.9 volts.

The only other time the engine is in open loop is after a cold start before the O2 sensors get up to their 600F operating temp.

If the full throttle turns out okay then the only problem remaining is getting a proper AFR at idle and cruise with the AIS disconnected. The variable resistors would work if one knew what range was needed. The O2 generates its own voltage and if it's hot enough is still working after the ignition is cut off. One wire is the signal wire and the other is the ground which is necessary because of the very low voltages generated. The resistors would need to be between the sensors and the computer in the signal wire and the connections would need to be soldered so there is absolutely no voltage drop at the connections. Then all that would be necessary is to adjust them so the average O2 reading is 0.45 volt or maybe a tad more at about 2000 rpm's on a stationary bike.

There is one drawback to resistors - the resistance invariably changes with changes in temperature so you would need to pick a happy medium.

Please excuse my ignorance but what is HHO?

I have to also agree with Rich {TampaSVT} on this one, Less is Best, I removed my AIS with NO POWER COMANDER in 2009, and Never looked back since, This freakin bike runs like a well oiled machine

Oh BTW, thanks Rich, for AIS advice you gave me back in 2009, it worked like a charm...

Rich, I didn't mean that in a way to offend you, I don't think either one of us claimed or indicated we are experts, I sure as heck ain't.

Why what? Why know fuel injection? Or why put on an after market controller? If the question is the latter, I want to know that too.
These sellers like dynojet want $359.00-$399.00 dollars for a couple transisters and resisters to shove in a little more fuel when the problem may be a detuned exhaust in the first place.

One guy says, "It does not allow adjustments in areas I don't care about, Like 50% throttle or less and below a certain rpm range."

Well..if this thing won't allow adjustments in the 50% throttle range I don't understand what the hell good it is to spend that kind of money on? Again I don't mean this in an offending way, I just don't get it. I mean if the computer goes into open loop at full throttle?

Don't the computer run in closed loop most of the average cruising time?

Scott HHO,,hydrogen-oxygen.

Blue, how many miles have you put on the bike since you took it off in 2009?

Hydrogen-Oxygen, thanks, I hadn't heard of that one before.

Some folks think that the modern cars run a lot leaner than the bikes. Well they don't and follows is the numbers from my 2009 Ford Focus with 28k miles:

Idle:
CO - 0.00%
HC - 0 ppm
CO2 - 13.5%
O2 - 1.45%
Lambda - 1.073
AFR - 15.77

3000 rpm's:
CO - 0.00%
HC - 0 ppm
CO2 - 14.3%
O2 - 0.18%
Lambda - 1.008
AFR - 14.82

The absence of HC and CO tells me that the catalyst is lit and functioning properly. At 3000 rpm's just about all of the oxygen is used up which indicates very good combustion.

Good figures to shoot for with the FI Roadie or even the carbureted for that matter.

I took those results down. I agree.